The final concentration assuming the volumes are additive when a 71.0 ml portion of a 1.50 m solution is diluted to a total volume of 258 ml. a 129 ml portion of that solution is diluted by adding 149 ml of water is 0.191 M
This can be solved by using the dilution factor.
So the dilution factor for the first dilution is 71.0 ml to 258 ml
DF1=258/71=3.63
For the first solution, the dilution factor is
3.163, refers that the concentration is decreased by a factor of 3.163.
The concentration of diluted solution is
c(diluted)=1.50/3.63=0.413
Now, you take a sample of 129 mL of this diluted solution and add another 165 mL of water. So,
V(final)=129ml +149 ml=278 mL
The concentration of the 129 mL sample is equal to the concentration of the first diluted solution, i.e. 0.413 M
So,
DF2=278/129=2.155
So, the final concentration is
c(final)=0.413/2.155=0.191 M
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A hiker climbs to the top of a mountain at rate of 0.5 me/hr. What are the speed and velocity of the hiker? middle school
A hiker climbs to the top of a mountain at rate of 0.5 m/hr. The speed of hiker is 1.3 x 10⁻⁴ m/s and the velocity of the hiker is 1.3 x 10⁻⁴ m/s west.
Speed is a scalar quantity. It is used to measure the distance traveled in a period of time. It is represented by -
s = d/Δt
where,
s = speed
d = distance
Δt = change in time
Velocity is a vector quantity. It is used to measure the change in position, that is, displacement over the change in time. It is represented by -
v = Δs / Δt
where,
v = velocity
Δs = change in position/displacement
Δt = change in time
The standard unit of velocity and speed both is m/s.
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what is the difference between an element and an isotope? an isotope is an element with a different number of electrons. an isotope is an element with a different number of neutrons. an isotope is an element with a different number of protons.
Answer:
different number of neutrons
Why can't you use the equation Q = mc∆T to calculate how much thermal energy is needed to melt or boil a substance?
We can't you use the equation Q = mc∆T to calculate how much thermal energy is needed to melt or boil a substance because this equation is to calculate for heat energy transferred between two objects where m is the mass of each object and c is the specific heat capacity
Thermal energy refers to the energy contained within a system that is responsible for its temperature and for thermal energy for melt any substance is latent heat and during boiling of any substances the heat energy supplied is used in increasing the energy of the water molecule which changes its state from liquid to gaseous
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determine the molarity of a solution formed by dissolving 50.54 g libr (86.84 g/mol) in enough water to yield 750.0 ml of solution. your answer should have three decimal places and no units.
The molarity of a solution is 3.743M.
Molarity of a solution:
Molar concentration is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of the amount of substance per unit volume of solution.
The formula for the molarity of a solution:
M = [tex]w_{B}[/tex] × 1000 / [tex]M_{B}[/tex] × V(ml)
[tex]w_{B}[/tex] = 50.54g
[tex]M_{B}[/tex] = molecular mass of water(H2O) = 2 + 16 = 18
V = Volume = 750ml
Putting the value in the equation, we get
M = 50.54 ×1000 / 18 × 750
= 50540 / 13500
= 3.743M
Therefore the molarity of a solution is 3.743M
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What is the atomic mass of hafnium if, out of every 100 atoms, 5 have a mass of 176, 19 have a mass of 177, 27 have a mass of 178, 14 have a mass of 179, and 35 have a mass of 180. 0?.
The average atomic mass of the given isotopes of Halfnium is 178.55 amu
The average atomic mass of an element is equal to the sum of its isotope masses multiplied by it's own natural abundance (the decimal associated with the percent of atoms of that element for a given isotope).
In order to determine the weighted average, we must consider the % natural abundances of each isotope. The atomic mass of an element is the weighted average of the atomic masses of the element's naturally occurring isotopes. Determine the average atomic mass by using atomic masses and percentage abundances of each isotope. To convert each percentage abundance to decimal form, divide it by 100. Multiply this figure by the atomic mass of the isotope. To get the average atomic mass, add the atomic masses of each isotope together.
To determine the average atomic mass of Halfnium, the mass fractions of the isotopes multiplied by their respected atomic masses must all be added.
Using 100 atoms as the basis, calculate the mass fractions (m1, m2,...m5):
m1 = 5/100 = 0.05
m2 = 19/100 = 0.19
m3 = 27/100 = 0.27
m4 = 14/100 = 0.14
m5 = 35/100 = 0.35
Multiplying the mass fractions with the atomic masses of the respective isotopes.
Average atomic mass of Halfnium is:
Avg = (m1 x 176) + (m2 x 177) + (m3 x 178) + (m4 x 179) + (m5 x 180)
Avg = (0.05 x 176) + (0.19 x 177) + (0.27 x 178) + (0.14 x 179) + (0.35 x 180)
Avg = 178.55 amu
Therefore, the average atomic mass of Halfnium based on the data for its given isotopes is 178.55 amu.
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i will give brainliest please help
1. A compound has an empirical formula of CO4 and a mass of 228 g/mol. What is the molecular formula?
2. What is simplest form (empirical formula) of C4H24O12?
The molecular formula is [tex]\rm C_2O_8[/tex]. The empirical formula is [tex]\rm C_2H_1_2O_6[/tex] which is the simplest from.
What is molecular formula?Molecular formula is defined as a chemical formula that gives the total number of atoms of each element in each molecule of a substance.
It can also be defined as a formula derived from molecules that indicates the total number of individual atoms in the molecule of a compound.
Empirical formula is defined as a chemical formula that depicts the simplest elemental ratio of a compound rather than the total number of atoms in the molecule.
Molecular formula = n - empirical formula
Thus, the molecular formula is [tex]\rm C_2O_8[/tex]. The empirical formula is [tex]\rm C_2H_1_2O_6[/tex] which is the simplest from.
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when 56.6 g of calcium is reacted with nitrogen gas, 31.0 g of calcium nitride is produced. what is the percent yield of calcium nitride for this reaction? 3ca(s) n2(g)→ca3n2(s)
Calculation of percent yield requires the theoretical yield to be calculated first. Using that method, the percent yield of the reaction is 44%.
To calculate the percent yield of calcium nitride, we first need to calculate the theoretical yield. To do this, we need the molar mass of both calcium (40 g/mol) and calcium nitride (3 * 40 + 2 * 14) g/mol = 148 g/mol.
3 moles of calcium produce 1 mol of calcium nitride so the proportion we can make will look like this:
120 g of calcium : 148 g of calcium nitride = 56.6 g of calcium : X
X = 148 g of calcium nitride * 56.6 g of calcium / 120 g of calcium
X = 69.8 g of calcium nitride
This is the theoretical yield. Calculating the percent yield works like this - we divide the actual mass by the theoretical yield and then multiply that number (that is always supposed to be between 0 and 1) by 100%:
%yield = 100% * 31.0 g / 69.8 g = 44%
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4. which parts of the amino acids x and y are involved in the formation of a peptide bond between them? assume that w is the first amino acid in the polypeptide chain, x is the second, and y is the third.
In a polypeptide chain, to generate an amide, the peptide bond connects the carboxyl group of one amino acid (x) to the amino group of the subsequent amino acid (y).
A polypeptide chain is defined as a series of amino acids linked together by peptide bonds. Poly stands for numerous, while peptide stands for protein. A polypeptide chain is therefore a chain of protein or amino acid building components. Polypeptide chains are crucial because they are the building blocks of proteins.
The carboxyl group of the first amino acid, w binds with the amino group of the next amino acid, x. The carboxyl group of x binds with the amino group of the y amino acid. Thus, peptide bonds are formed between the w-x-y amino acids making them a polypeptide chain.
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Identify the hybridization of the N atoms in N2H4
All of the nitrogen in the N2H4 molecule hybridizes to Sp3.
How does hybridization work?The combining of two atomic orbitals to create a whole new class of hybridized orbitals is the notion of hybridization in chemistry. Hybrid orbitals with completely distinct energies are often the outcome of this mixing. In hybridization, the same-energy level atomic orbitals are crucial. However, as long as they have an equivalent amount of energy, both fully and partially filled orbitals can participate in this process.
All of the nitrogen in the N2H4 molecule hybridizes to Sp3. N2H4 has a dipole moment of 1.85 D and is polar in nature. The nitrogen atoms in N2H4 have no formal charge. The N2H4 molecule has a trigonal molecular geometry (shape).
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WHAT IS THE SIZE OF MY D\
Answer:get a ruler and find out
Explanation:
measure from tip to tip and post a picture to see
Answer:baby carrots
Explanation:
measure with baby carr
suppose you did not want to calculate the precise atomic mass for one of the elements, such as nitrogen or oxygen. how could you approximate the value of the atomic mass?
The atomic mass of every element may be simply calculated using the number of protons and neutrons in the nucleus.
The atomic mass can be approximated by summing the number of protons and neutrons in the atom. The average mass of an element's atoms that are meaningfully measured in the atomic mass unit (amu) is defined as its atomic mass. It should be noted that the atomic mass is calculated by adding the masses of all the element's isotopes. This is the most precise method for calculating the relative atomic mass.
However, if we do not wish to compute the precise atomic mass of one of the elements, we may simply sum the number of protons and neutrons in the atom. This provides us a ballpark estimation of the atom's mass. Another way for estimating the atomic mass of any element is to simply double the value of the atomic number that is known for each individual element.
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A student with long hair (or loose clothing) is heating a solution over a Bunsen burner. As the student leans over the burner to reach for something, their hair (or clothing) catches fire.
Get the fire blanket and notify the teacher.
If your clothing catches fire do not run or do anything else to fan the flames. Immediately drop it on the ground and roll it to extinguish the flames. The laboratory is also equipped with fire blankets to extinguish clothing fires. Used by instructors as needed to completely extinguish flames.
Long hair should be tied up and long sleeves should not be worn. Always keep hair clothing, and hands at a safe distance from flames. Never touch the open flame with your hands. Use tongs when holding objects in flames. Long hair can fall on lab benches or come into contact with chemical or biological agents.
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1. What are hormones
Answer: Hormones are are the body's chemical messengers, sending signals into the bloodstream and tissues. Hormones work slowly, over time, and affect many different processes, including growth and development, metabolism – how your body gets energy from the foods you eat- sexual function, reproduction, and mood
Question 9What pressure will be exerted by 15 g of carbon dioxide gas in a 20 L container at 0 °C?
In this question, we need to find the value of pressure of a 15 grams sample of CO2 gas, and in order to find this value, we will be using the Ideal gas law formula, which is the following:
PV = nRT
Where:
P = pressure in atm
V = volume in liters, 20 Liters
n = number of moles
R = gas constant, 0.082
T = temperature in kelvin, 0°C = 273 K
The number of moles we need to find based on the mass in the question and based on the molar mass of CO2, 44g/mol:
44g = 1 mol
15g = x moles
44x = 15
x = 15/44
x = 0.34 moles of CO2 in 15 grams
Now we have the values to add to the formula:
P * 20 = 0.34 * 0.082 * 273
20P = 7.61
P = 7.61/20
P = 0.38 atm of pressure
The pressure will be 0.38 atm
a solution containing 3.76 g naoh in 361 ml water is titrated to the endpoint with 491 ml hcl. what is the molar concentration of hcl in the original solution? a. 0.13 b. 130 c. 0.0031 d. 0.00053 e. 0.19
The molar concentration of HCl in the original solution is 0.19
The balanced chemical equation for the reaction must be our starting point because it will provide us with the reactants' mole ratios and allow us to answer this question.
* NaOH + HCl --> NaCl + H2O
this means:
1 mole NaOH reacts with 1 mole HCl
thus the ratio of NaOH to HCl is 1: 1
Next we've got to calculate the moles of NaOH: (molecular Mass = 40 g/mol)
moles(NaOH) = 3.76g/40
= 0.094 moles
Now we can calculate the concentration of NaOH:
Note: 361mL/1000 = 0.361L
conc(NaOH) = 0.094 moles/0.361L
= 0.26 mol/L
Now the mole ratio of NaOH to HCl is 1:1
But we have used only 0.094 moles so since the ratio of NaOH to HCl is 1:1, it means that 0.094moles of NaOH can only react with 0.094 moles of HCl.
Note: 491mL/1000mL = 0.491L
conc(HCl) = 0.094 moles/0.491L
= 0.19 mol/L
Thus the molar concentration of HCl in the original solution is 0.19
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Students will design an experiment to find out if brand X fertilizer will affect the growth of Lily
plants. Remember a fair experiment only has ONE (1) Independent Variable. In this experiment,
The independent variable as we can see from the experiment that have been described in this case is the brand of fertilizer that was used in the study.
What is an experiment?When we talk about an experiment, we are talking about the way by which the relation ship between the dependent and the independent variable could be studied. In the experiment, there is a dependent variable which would change values when the variable that is under study in the particular experiment changes value. We have to know that in the realm if science, it is only by the means of experiments that we can be able to establish cause and effect relationships.
In this case, we can see that the experiment that the students were working on has to do with trying to actually find out if brand X fertilizer will affect the growth of Lily plants. This means that they were studying the effect of a fertilizer brand on the growth of the crops.
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A 24.20 g sample of a metal displaces 1.26 mL of water. Calculate the density of the metal.
19.2g/cm³
D = m / V
24.20g / 1.92ml = 19.2g/cm³
Heat can bring about chemical reactions and chemical reactions can produce heat. is this also true for light and heat? give an example to illustarte each case.
Yes, there are chemical reactions that are brought about through the use of light (such as free radical halogenation) and there are chemical reactions that produce light (chemiluminescence).
Numerous reactions use light as an initiator. For example, in various examples of free radical halogenation (a reaction between a hydrocarbon and a halogen molecule, where alkyl halides are formed), light is needed to break the bond between the bromine atoms in order to form bromine radicals that then initiate the chain reaction leading to the formation of the product.
The phenomenon of producing light through a chemical reaction is called chemiluminescence. It is relatively rare, but not unheard of. One example is the reaction between luminol and hydrogen peroxide, which forms 3-aminophthalate and releases light.
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Balance the equations.
MgO + HBr → MgBr₂ + H₂O
Answer:
Since there is an equal number of each element in the reactants and products of MgO + 2HBr = MgBr2 + H2O, the equation is balanced.
group 1 got 113.8-115.4°c and group 2 got 108.3-116.3°c. which group had the better data and why? list 3 ways that the groups could improve their results in terms of the crystallization experiment and the melting point investigation.
The group with a better result is group 1
Three ways that the groups could improve their results in terms of the crystallization experiment and the melting point investigation are: recrystallisation, elimination of impurity, and heating the solvent.
Group 1's result is better, it is so because they have got the melting point range in a close proximity, that means they do not have a broad range. Smaller the range of melting point, more accurate the compound is synthesized.
3 ways that the groups could improve their results:
Recrystallisation again and again by using any volatile solvent such as ethanol, petroleum ether By eliminating the impurity. If eliminating the impurity will not work well then heat the solvent along with the compound and place it for recrystallisation. This will surely work out.Learn more about crystallization experiment here:
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The chemical formula for glucose, a simple sugar, is c6h12o6. When a glucose molecule is assembled during photosynthesis, the process takes up 12 hydrogen ions from the stroma of the chloroplast. What process adds 12 hydrogen ions to the chloroplast?.
Light energy is used in photosynthesis to convert carbon dioxide and water into glucose and oxygen. 1 glucose molecule and 6 oxygen molecules are produced for every 6 carbon dioxide and 6 water molecules.
C₆H₁₂O₆ is the chemical formula for glucose, a simple sugar. When a glucose molecule is assembled during photosynthesis, it absorbs 12 hydrogen ions from the chloroplast stroma. Reactants in photosynthesis include oxygen, carbon dioxide, ATP, and NADPH. Water and GA3P are both products. Chlorophyll, water, and carbon dioxide are reactants in photosynthesis. When the process is finished, photosynthesis produces oxygen and carbohydrate molecules, most commonly glucose. These sugar molecules contain the energy required by living things to survive.
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find values of the intrinsic carrier concentration n. for silicon at -55°c, 0°c, 20°c, 75°c, and 125°c. at each temperature, what fraction of the atoms is ionized? recall that a s
The intrinsic carrier concentration and the fraction of ionized atoms of silicon at -55℃, 0℃, 20℃, 75℃, 125℃ is calculated below.
The intrinsic carrier concentration in intrinsic material is the number of electrons found in the conduction band or holes in the valence band. This quantity of carriers is determined by the material's band gap as well as its temperature.
Because the number of holes equals the number of electrons, the concentration of each is equal to some amount, ni, and this quantity is known as the intrinsic carrier concentration, and the pure semiconductor material is referred to as intrinsic material.
Given:
B = 5.4 x [tex]10^{31}[/tex]
[tex]E_G[/tex] = 1.12 ev for silicon
K = 8.62 x [tex]10^{-5}[/tex]
Silicon crystal = 5 x [tex]10^{22}[/tex] atoms/[tex]cm^3[/tex]
To find:
Intrinsic carrier concentration, ni = ?
Fraction of ionized atom = ?
Formula:
[tex]ni^2 = BT^3 e^{\frac{-E_G}{KT}[/tex]
Fraction of ionized atom = ni / 5 x [tex]10^{22}[/tex]
Calculations:
(a) For -55℃:
T = -55 + 273 = 218K
ni = [tex]5.4 * 10^{31} * 218^3 * e^{(\frac{-1.12}{8.62 * 10^{-5} * 218})}[/tex]
ni = 2.7018 x [tex]10^6[/tex] carriers/[tex]cm^3[/tex]
Fraction of ionized atom = 2.7018 x [tex]10^6[/tex] / 5 x [tex]10^{22}[/tex]
Fraction of ionized atom = 5.403 x [tex]10^{-17}[/tex] atoms/[tex]cm^3[/tex]
(b) For 0℃:
T = 0 + 273 = 273K
ni = [tex]5.4 * 10^{31} * 273^3 * e^{(\frac{-1.12}{8.62 * 10^{-5} * 273})}[/tex]
ni = 1.53 x [tex]10^9[/tex] carriers/[tex]cm^3[/tex]
Fraction of ionized atom = 1.53 x [tex]10^9[/tex] / 5 x [tex]10^{22}[/tex]
Fraction of ionized atom = 3.07 x [tex]10^{-14}[/tex] atoms/[tex]cm^3[/tex]
(c) For 20℃:
T = 20 + 273 = 293K
ni = [tex]5.4 * 10^{31} * 293^3 * e^{(\frac{-1.12}{8.62 * 10^{-5} * 293})}[/tex]
ni = 8.65 x [tex]10^9[/tex] carriers/[tex]cm^3[/tex]
Fraction of ionized atom = 8.65 x [tex]10^9[/tex] / 5 x [tex]10^{22}[/tex]
Fraction of ionized atom = 1.73 x [tex]10^{-13}[/tex] atoms/[tex]cm^3[/tex]
(d) For 75℃:
T = 75 + 273 = 348K
ni = [tex]5.4 * 10^{31} * 348^3 * e^{(\frac{-1.12}{8.62 * 10^{-5} * 348})}[/tex]
ni = 3.724 x [tex]10^{11}[/tex] carriers/[tex]cm^3[/tex]
Fraction of ionized atom = 3.724 x [tex]10^{11}[/tex] / 5 x [tex]10^{22}[/tex]
Fraction of ionized atom = 7.449 x [tex]10^{-12}[/tex] atoms/[tex]cm^3[/tex]
(e) For 125℃:
T = 125 + 273 = 398K
ni = [tex]5.4 * 10^{31} * 398^3 * e^{(\frac{-1.12}{8.62 * 10^{-5} * 398})}[/tex]
ni = 4.75 x [tex]10^{12}[/tex] carriers/[tex]cm^3[/tex]
Fraction of ionized atom = 4.75 x [tex]10^{12}[/tex] / 5 x [tex]10^{22}[/tex]
Fraction of ionized atom = 9.51 x [tex]10^{-11}[/tex] atoms/[tex]cm^3[/tex]
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a certain first order reaction has a half-life of 41.3 s. how long will it take (in s) for the reactant concentration to decrease from 6.50 m to 2.06 m? give your answer to three sig figs
The time needed to decrease reactant concentration based on its half-life is 68.47 seconds.
We need to know about the half-life of the radioactive elements to solve this problem. The radioactive element will decay over time and follow the equation
N = No(1/2)^(t/t'')
where N is the final quantity, No is the initial quantity, λ is the decaying constant, t is time and t'' is the half-life of a radioactive element.
From the question above, we know that
t'' = 41.3 s
No = 6.5 m
N = 2.06 m
By substituting the given parameters, we can calculate the time taken
N = No(1/2)^(t / t'')
2.06 = 6.5 . (1/2)^(t / 41.3)
0.32 = (1/2)^(t / 41.3)
⁰'⁵log(0.32) = t / 41.3
1.66 = t / 41.3
t = 68.47 seconds
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The only transition metal that is a liquid at room temperature
(21 °C) is named
Answer:
mercury
Explanation:
mercury is a metal on the periodic table which is liquid at room temperature
can someone help me with balancing this chemical equation?
( ^ means subscript )
NH^3+0^2= NO+H^2O
This chemical equation is balanced.
What is chemical equation?
chemical equation are symbolic representation of chemical reactions in which the reactants and the product are expressed in term of their respective chemical formula.
Reactants are converted to products and the process is symbolise by a chemical equation.
Sol-
NH^3+O^2------>NO+H^2O
2NH^3+O^2----->2NO+3H^2O
2NH^3+O^2------>2NO+3H^2O
2NH^3+5/2 O^2------2NO+3H^2O
2NH^3+5/2 O^2------->2NO+3H^2O
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In a constant-pressure calorimeter of negligible heat capacity, 25 ml of 1. 00 m cacl2 is mixed with 25 ml of 2. 00 m kf, resulting in solid caf2 precipitating out of the solution. During this process, the temperature of the water rises from 25. 0°c to 26. 7°c. Assume the specific heat capacity of the solution is 4. 184 j/°c•g and the density of the solution is 1. 00 g/ml. Calculate the enthalpy of precipitation in kj per mole of caf2 precipitated.
The enthalpy of precipitation of calcium fluoride is -13.974 kJ/mol.
In order to solve this, first we need to write the balanced chemical reaction equation of the reaction in question:
CaCl₂(aq) + 2KF(aq) → CaF₂(s) + 2KCl(aq)
In order to calculate the enthalpy of precipitation (ΔH), we need the amount of heat released (Q) and the number of moles of CaF₂ (n):
ΔH = Q/n
To calculate the number of moles, we can use the molarity (c = 1.00 M) of the calcium chloride solution and its volume (V = 25 mL = 0.025 L):
c = n/V ⇒ n = c*V
n = 1.00 M * 0.025 L = 0.025 mol
We calculate the amount of heat released (Q) using the following equation:
Q = (t₁ - t₂) * C * m
t₁ - initial temperature (25.0 ⁰C)
t₂ - final temperature (26.7 ⁰C)
C - specific heat capacity (4.184 J/⁰Cg)
m - the mass of the solution
We need the mass of the solution, which we can calculate using the density (d = 1.00 g/mL) and the volume (V = 25 mL + 25 mL = 50 mL) of the solution:
d = m/V ⇒ m = d*V
m = 1.00 g/mL * 50 mL = 50 g
Q = (25.0 ⁰C - 26.7 ⁰C) * 4.184 J/°Cg * 50 g
Q = -349.4 J
ΔH = -349.4 J / 0.025 mol
ΔH = -13974 J/mol = -13.974 kJ/mol
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If an Oreo cookie is 0.69 cm thick (1 cookie = 0.69 cm), how many Oreos does it take to reach the moon if the moon is 3.84 x 10^8 m away from earth?
It takes 5.89 x 10¹⁰ Oreos to reach the moon.
The average distance from the Earth to the moon is 385 000.6 km.
Metres = 385 000.6 km × (1000 m/1 km ) = 385 000 600 m
Centimetres = 38 500 060 000 m × (100 cm/1 m) = 38 500 060 000 cm
Oreos = 38 500 060 000 cm × (1 Oreo/0.654 cm) = 58 900 000 000 Oreos
= 5.89 x 10¹⁰ Oreos
Its diameter is around one-quarter that of the Earth (comparable to the width of Australia). The Moon is the Solar System's fifth-largest satellite. It is the largest (and most massive) satellite relative to its home planet and is larger than any other known dwarf planet. [f] According to geophysical criteria, the Moon is a planetary-mass object that became a differentiated rocky body, making it a satellite planet. There is no atmosphere, hydrosphere, or magnetic field. Its surface gravity is around one-sixth that of Earth (0.1654 g). Io, Jupiter's moon, has the highest surface gravity and density of any satellite in the Solar System.
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An atom of Iodine contains 75 neutrons. What is its mass number?
Answer:
128
Explanation:
Iron has atomic number of 53
so mass number is 53 + 75 = 128
the lead-acid storage battery is the oldest rechargeable battery in existence. it was invented in by french physician gaston plante and still retains application today, more than years later. there are two reactions that take place during discharge of the lead-acid storage battery. in one step, sulfuric acid decomposes to form sulfur trioxide and water: (l) (g) (l) in another step, lead, lead(iv) oxide, and sulfur trioxide react to form lead(ii) sulfate: (s) (s) (g) (s) calculate the net change in enthalpy for the formation of one mole of lead(ii) sulfate from lead, lead(iv) oxide, and sulfuric acid from these reactions. round your answer to the nearest .
The net change in enthalpy for the formation of one mole of lead(ii) sulfate from lead, lead(iv) oxide, and sulfuric acid is -274.5 KJ,
Calculation
Reaction 1: [tex]H_{2} SO_{4(aq)}--- > SO_{3(g)} +H_{2} O_{(l)}[/tex] , Δ[tex]H^{Q} = +113 KJ[/tex]
Reaction 2: [tex]Pb_{(s)} +PbO_{2(s)} +2SO_{3(s)} --- > 2PbSO_{4(aq)}[/tex] Δ[tex]H^{Q} =-775 KJ[/tex]
To calculate the net change in enthalpy for the formation of 1 mole of [tex]PbSO_{4(aq)}[/tex]
Divide reaction 2 by 2
⇒[tex]\frac{Pb_{(s)}}{2} +\frac{PbO_{2(s)}}{2} +\frac{2SO_{3(s)}}{2} --- > \frac{2PbSO_{4(aq)}}{2}[/tex], Δ[tex]H^{Q} =\frac{-775}{2} KJ[/tex]
⇒[tex]\frac{Pb_{(s)}}{2} +\frac{PbO_{2(s)}}{2} +SO_{3(s) --- > PbSO_{4(aq)[/tex] , Δ[tex]H^{Q} =-387.5 KJ[/tex]
Subtract reaction 1 with the above reaction
[tex]H_{2} SO_{4(aq)}--- > SO_{3(g)} +H_{2} O_{(l)}-\frac{Pb_{(s)}}{2} +\frac{PbO_{2(s)}}{2} +SO_{3(s) --- > PbSO_{4(aq)[/tex]
⇒[tex]H_{2} SO_{4(aq)}+\frac{Pb_{(s)}}{2}+\frac{PbO_{2(s)}}{2} --- > PbSO_{4(aq)}+H_{2} O_{(l)}[/tex]
Δ[tex]H^{Q}[/tex]=Δ[tex]H^{Q} Product[/tex]+Δ[tex]H^{Q} Rreactant= -387.5 KJ+113 KJ[/tex]
Δ[tex]H_{formation} =-274.5 KJ[/tex]
What is the enthalpy change?An enthalpy change is roughly equivalent to the energy gained through the production of new chemical bonds in a reaction minus the energy required to break existing chemical bonds. It describes how a system changes in terms of energy while pressure is constant. The symbol H stands for enthalpy change. At constant pressure, H is equal to the sum of the system's internal energy and the pressure-volume work it performs on its surroundings.To learn more about enthalpy change, refer to https://brainly.com/question/16387742
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how many milliliters of 3.0m naoh are required to react with 0.5g of cu 2 to form cu(oh)2? ( hint: write the net ionic equation for reaction 2, to get correct mole ratio) ( answer should be written in decimal form)
The number of milliliters of 3.0m NaOH required to react with 0.5g of Cu2+ to form Cu(OH)2 is 5.249 ml
The reaction is as follows;
2NaOH + Cu2+ ------------> Cu(OH)2 + 2Na+
From the balanced chemical reaction, 0.5 g of Cu2+ = 0.5/63.5 = 7.874x10-3 moles (molar mass of Cu2+ = 63.5 g)
Thus, moles of NaOH required = 2*moles of Cu2+ = 0.01575
Now, moles of NaOH = molarityxvolume in litres
or, 3*volume in litres = 0.01575
or, volume in litres = 5.249*10-3 litres = 5.249 ml
A balanced chemical equation is one that contains the same number of atoms on either side of the equation.It follows the law of conservation of mass.To learn more about balanced chemical equation visit:
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