Answer:
5
Explanation:
Answer:
5
Explanation:
What is the name of PbS2
Answer:
Lead sulfide.
Explanation:
Gallium (Ga, 69.723 g/mol) is a metalloid obtained from its salts during the smelting of ores of other elements, like Zinc. has broad applicability in the electronics industry. It is also used as a safe replacement for mercury in thermometers as it melts at 29.8 °C and has a heat of fusion of 5.59 kJ/mol. What is the entropy change of 22 g of gallium in J/K as it melts when placed on a surface at 29.8°C?
Answer:
4.255 J/ K
Explanation:
Given data :
mass of Gallium = 16 gm
molar mass = 69.723 g/mol
hence no of moles = 16 / 69.723 = 0.23 moles --------- ( 1 )
Δh ( heat fusion ) = 5.59 KJ/mol
Temperature = 29.8°C = 302.8 k
Determine the entropy change of gallium
Δs ( entropy change ) = heat fusion / temperature
= ( 5.59 * 1000) J/mol / 302.8 = 18.46 J/k*mol
Hence entropy change of gallium
= Δs * no of Gallium moles
= 18.46 * 0.23 = 4.255 J/ k
I hope this is right haha
Nitrogen monoxide is produced by combustion in an automobile engine. For the following reaction, 6.42 grams of nitrogen monoxide are mixed with excess oxygen gas . The reaction yields 8.53 grams of nitrogen dioxide . nitrogen monoxide ( g ) oxygen ( g ) nitrogen dioxide ( g ) What is the theoretical yield of nitrogen dioxide
Explanation:
[tex]6.42 \times \frac{1}{30} \times \frac{1}{1} \times \frac{46}{1} = 9.844[/tex]
[tex]8.53 \div 9.844 \times 100 = 86.65\%[/tex]
3.00 g of a fuel (MW = 650.0 g/mol) is combusted in a bomb calorimeter. The temperature of the calorimeter increases by 25.0 degrees Celsius. The heat capacity for the calorimeter has been determined to be 9.001kJ/C. What is the heat of reaction (in kJ/mol)?
Answer:
-4.88 × 10⁴ kJ/mol
Explanation:
Step 1: Calculate the heat gained by the calorimeter (Qcal)
We will use the following expression.
Qcal = C × ΔT
where,
C: heat capacity of the calorimeterΔT: temperature changeQcal = 9.001 kJ/°C × 25.0°C = 225 kJ
Step 2: Calculate the heat released by the fuel
According to the law of conservation of energy, the sum of the heat released by the fuel (Qf) and the heat absorbed by the calorimeter is zero.
Qf + Qcal = 0
Qf = -Qcal = -225 kJ
Step 3: Calculate the heat of reaction in kJ/mol
3.00 g of a fuel (MW = 650.0 g/mol) released 225 kJ of heat. The heat of reaction is:
-225 kJ/3.00 g × 650.0 g/mol = -4.88 × 10⁴ kJ/mol
What do you think the biggest risk with genetic engineering is?
Answer:
Harmful toxins from crops have been found in peoples blood.
GM crops can cause allergic reactions in crops
Its dangerous to mess with nature this way when it should be a natural thing.
Explanation:
I'm in both Biology and Chemistry so I know a lot!
if the amounts of greenhouse gases such as carbon dioxide and methane continue to increase in the atmosphere, what will happen to the average temperature of Earth?
If greenhouse gases in the atmosphere continues to increase, then the
average temperature of Earth will increase too.
Greenhouse gases such as carbon dioxide and methane deplete the ozone
layer which shields the earth from radiations from the Sun. An increase in
these gases will therefore allow for more radiations to get to the earth.
This therefore brings about an increase in the average temperature of the
earth.
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how many hydrogen molecules are there in 1 ton of hydrogen?
Considering the definition of mass molar and Avogadro's Number, there are 3.0115×10²⁹ molecules in 1 ton of hydrogen.
First, the molar mass of hydrogen H₂, that is, the amount of mass that a substance contains in one mole, is 2 g/mole.
In this case, being 1 ton = 1,000,000 grams, the number of moles that 1 ton of hydrogen contains is calculated as:
[tex]1,000,000 gramsx\frac{1 mole}{2 grams} = 500,000 moles[/tex]
On the other hand, Avogadro's Number is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole.
Then, the number of molecules that 500,000 moles of hydrogen contains is calculated as:
[tex]500,000 molesx\frac{6.023x10^{23} molecules }{1 mole}[/tex]= 3.0115×10²⁹ molecules
Finally, there are 3.0115×10²⁹ molecules in 1 ton of hydrogen.
Learn more about:
mass molar: https://brainly.com/question/12695086?referrer=searchResultsAvogadro's Number: brainly.com/question/11907018?referrer=searchResults brainly.com/question/1445383?referrer=searchResults brainly.com/question/1528951?referrer=searchResultsCombustion of hydrocarbons such as octane (C_8H_18) produces carbon dioxide, a "greenhouse gas." Greenhouse gases in the Earth's atmosphere can trap the Sun's heat, raising the average temperature of the Earth. For this reason there has been a great deal of international discussion about whether to regulate the production of carbon dioxide.
1. Write a balanced chemical equation, including physical state symbols, for the combustion of liquid octane into gaseous carbon dioxide and gaseous water.
2. Suppose 0.330 kg of octane are burned in air at a pressure of exactly 1 atm and a temperature of 10.0 ?C. Calculate the volume of carbon dioxide gas that is produced. Round your answer to 3 significant digits.
Answer: 1. [tex]2C_8H_{18}(l)+25O_2(g)\rightarrow 16CO_2(g)+18H_2O(g)[/tex]
2. The volume of carbon dioxide gas that is produced is 537 L
Explanation:
1. Combustion is defined as the type of chemical reaction where a hydrocarbon is combusted in the presence of oxygen to give carbon dioxide and water.
The balanced reaction for combustion of octane is:
[tex]2C_8H_{18}(l)+25O_2(g)\rightarrow 16CO_2(g)+18H_2O(g)[/tex]
2.
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex] [tex]\text{Moles of octane}=\frac{0.330\times 1000g}{114.23g/mol}=2.89moles[/tex]
According to stoichiometry:
2 moles of octane produce = 16 moles of carbon dioxide
2.89 moles of octane produce = [tex]\frac{16}{2}\times 2.89=23.1moles[/tex] of carbon dioxide
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 1 atm
V = Volume of gas = ?
n = number of moles = 23.1
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature =[tex]10.0^0C=(10+273)K=283K[/tex]
[tex]V=\frac{nRT}{P}[/tex]
[tex]V=\frac{23.1\times 0.0821Latm/K mol\times 283K}{1atm}=537L[/tex]
Thus the volume of carbon dioxide gas that is produced is 537 L
The following pairs of soluble solutions can be mixed. In some cases, this leads to the formation of an insoluble precipitate. Decide, in each case, whether or not an insoluble precipitate is formed.
a. AlCl3 and K3PO4
b. RbCO3 and NaCl
c. Na2CO3 and MnCl2
d. K2S and NH4Cl
e. CaCl2 and (NH4)2CO3
Answer:
See explanation
Explanation:
Let us see what happens when each solution is mixed;
a) AlCl3(aq) + K3PO4(aq) ------> 3KCl(aq) + AlPO4(s)
A precipitate is formed here
b) RbCO3(aq) + NaCl(aq) -------> This is an impossible reaction hence no solid precipitate is formed here
c) MnCl2(aq) + Na2CO3(aq) → 2NaCl(aq) + MnCO3(s)
A precipitate is formed.
d) K2S(aq) + 2NH4Cl(aq) ------> 2KCl(aq) + (NH4)2S(aq)
No solid precipitate is formed
e) CaCl2(aq) + (NH4)2CO3(aq) → CaCO3(s) + 2NH4Cl(aq)
A solid precipitate is formed
Which group of reptiles is the largest in terms of body size?
Answer : if you have time for learning and is in 6th grade the anwser is crocodilians
Explanation: i got it right
The diagram shows the sun's interior Convection are present in the convection zone Which describes how fluids change as they travel through the convection zone? Convection zone Radiation zone Core O They change to solids near the Sun's surface. They change to solids near the Sun's radiation zone O They become more dense near the Sun's surface. O They become more dense near the Sun's radiation zone
Answer:
C: They become more dense near the Sun's surface.
Explanation:
I got it correct on EDG
I hope this helps!!!!!!!!
Can I have a brainliest
According to convection, the statement which describes how fluids change as they travel through the convection zone is that they become more dense near the Sun's surface.
What is convection?Convection works by areas of a liquid or gas heating or cooling greater than their surroundings, causing differences in temperature. These temperature differences then cause the areas to move as the hotter, less dense areas rise, and the cooler, more dense areas sink.
Often the areas of heating and cooling are fixed, and allow convective cycles or currents to become established. For example, a saucepan of water over a flame may develop convective currents as the water is heated from below, rises to the surface, and cools. Once cooled enough, the water then sinks back to the bottom of the saucepan where the cycle is repeated, and the convective overturning continues.
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ASAP PLEASE!!! Approximately how much more of the solute potassium chlorate can be added to water if the temperature increases from 30°C to 65°C?
Answer: You have a solution of potassium chlorate containing 4 g at 65º C. How many additional grams of solute must be added to it, to make the solution saturated ? approximately 26 more grams [the solubility of potassium chlorate is ... water. The solution is allowed to cool. At what new temperature would crystals begin to.
Explanation:
what is the last element in the periodic table?
Answer:
Ununoctium
Explanation:
It's at the very end of the periodic table
Answer:
Ununoctium
Explanation:
Ununoctium is the last chemical element int the periodic table.
You read a primary source and a secondary source that discuss the same
experiment. There is a difference in the conclusions made by these two
sources. Which should you trust more, and why?
A. The primary source, because it is more confusing
B. The secondary source, because it is published in a well-respected
newspaper
C. The secondary source, because it is easier to read
D. The primary source, because it is written by the scientist who did
the work
Answer:
i think it's D tbh, just cus it was the scientist who did the work
Answer:
It depends on secondary sources and references of that secondary source. If it references just that primary source I would compare both of them and see the difference between them. Generally primary sources are more reliable but this situation is different.
O2 + 2C0-2CO2
4.62 grams of oxygen and 2.98 grams of carbon monoxide are placed in a closed
reaction vessel and the mixture is ignited. Combustion occurs until one of the
gases is totally consumed.
1. Identify the limiting reagent and the excess reagent
2. Determine the amount of excess reagent.
3. Calculate the grams of carbon dioxide produced.
Answer: 1. [tex]CO[/tex] is the limiting reagent and [tex]O_2[/tex] is the excess reagent.
2. 2.91 g of excess reagent
3. 4.66 g of carbon dioxide produced.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} CO=\frac{2.98g}{28g/mol}=0.106moles[/tex]
[tex]\text{Moles of} O_2=\frac{4.62g}{32g/mol}=0.144moles[/tex]
[tex]O_2+2CO\rightarrow 2CO_2[/tex]
According to stoichiometry :
2 moles of [tex]CO[/tex] require = 1 mole of [tex]O_2[/tex]
Thus 0.106 moles of [tex]CO[/tex] will require=[tex]\frac{1}{2}\times 0.106=0.053moles[/tex] of [tex]O_2[/tex]
Thus [tex]CO[/tex] is the limiting reagent as it limits the formation of product and [tex]O_2[/tex] is the excess reagent.
Amount of excess reagent = ( 0.144-0.053) moles = 0.091 moles
Mass of excess reagent [tex]O_2=moles\times {\text {Molar mass}}=0.091moles\times 32g/mol=2.91g[/tex]
As 2 moles of [tex]CO[/tex] give = 2 moles of [tex]CO_2[/tex]
Thus 0.106 moles of [tex]CO[/tex] give =[tex]\frac{2}{2}\times 0.106=0.106moles[/tex] of [tex]CO_2[/tex]
Mass of [tex]CO_2=moles\times {\text {Molar mass}}=0.106moles\times 44g/mol=4.66g[/tex]
Give the IUPAC name for the following alkanes and cycloalkanes
Answer:
1.3-bromo,2-chloro,4-floro hexane
3.bromocyclo pentane
What happens to the water molecules when water at 24°C is cooled to 0°C
and freezes?
pls help its due tmr
giving brainliest
What is the relationship between radius and diameter
Answer:
the radius is half the diameter
The radius of a circle is equal to half the diameter.
plz someone help me i dont get this and i need to finish this
Answer:
The height of A is 900
Explanation: Beside A, there is a number which explains what the height is so the answer is A.
A gas has a volume of 590 mL at a temperature of –55.0°C. What The temperature be if the volume expands to 15L at constant pressure?
Answer:
5542.37 K
Explanation:
Given that,
Initial volume, V₁ = 590 mL
Initial temperature, T₁ = -55°C = -55 + 273 = 218 K
Final volume, V₂ = 15 L
We need to find the final temperature of the gas. The relation between the volume and the temperature is given by :
[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]
Where
T₂ is final volume of the gas
Put all the values in above relation,
[tex]T_2=\dfrac{V_2T_1}{V_1}\\\\T_2=\dfrac{15\ L\times 218\ K}{590\times 10^{-3}\ L}\\\\T_2=5542.37\ K[/tex]
So, the required temperature is equal to 5542.37 K.
Hydrocyanic acid is a weak acid. Therefore, the salt KCN is
Question 4 options:
Basic
Amphoteric
Neutral
Acidic
KBr is the formula for an ionic compound. The fact that neither symbol is followed by a subscript means that there is a(an) of ions in the compound
Answer:
equal number of ions
Explanation:
They cancel each other out that's why there is none
If you obtain 3.0 grams of aspirin from an experiment that could make no more than 3.14 grams, what is the percent yield?
87%
105%
96%
92%
Answer:
96%
Explanation:
To find the percent yield, we can use this equation
[tex]\frac{Actual}{Theoretical} *100[/tex]
The actual yield of aspirin is 3.0 and the theoretical is 3.14 in this case, so just plug the numbers in.
[tex]\frac{3.0}{3.14} *100\\\\ =96[/tex]
Thus the percent yield is 96%
;)
True or false, rewrite it to make it true.
To balance a chemical equation, only the subscripts of a reactant and product can be changes
Answer:
false
Explanation:
what is elimination reaction
How is this effect of dissolved
substances important in nature?
Explanation:
Water is called the "universal solvent" because it is capable of dissolving more substances than any other liquid. This is important to every living thing on earth. It means that wherever water goes, either through the air, the ground, or through our bodies, it takes along valuable chemicals, minerals, and nutrients.
The electrons in an atom tend to assume the arrangement that gives the atom the least possible energy
T
F
The given statement is correct or true.
• The alignment of electrons in an atom is termed as the electronic configuration.
• The electrons in an atom seem to assume the alignment, which gives the atoms the least possible energy.
• This alignment of electrons is the most stable alignment and is known as the atom's ground-state electronic configuration.
• In the ground state of an atom, the electron first enters the lowest energy orbital and later subsequent electrons are aligned in order of increasing energy. This is known as the Aufbau principle.
Thus, the given statement is true or correct.
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Nickel carbonyl decomposes to form nickel and carbon monoxide, like this:
Ni(CO)4 → Ni + 4CO
At a certain temperature, a chemist finds that a 2.7L reaction vessel containing a mixture of nickel carbonyl, nickel, and carbon monoxide at equilibrium has the following composition:
Compound Amount
Ni(CO)4 0.597g
Ni 12.7g
CO 1.98g
Calculate the value of the equilibrium constant for this reaction. Round your answer to significant digits.
Answer: The value of the equilibrium constant for this reaction is [tex]2.8\times 10^{-5}[/tex]
Explanation:
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]
Moles of [tex]Ni(CO)_4[/tex] = [tex]\frac{0.597g}{170.7g/mol}=0.0035moles[/tex]
Moles of [tex]Ni[/tex] = [tex]\frac{12.7g}{58.7g/mol}=0.216moles[/tex]
Moles of [tex]CO[/tex] = [tex]\frac{1.98g}{28.01g/mol}=0.071moles[/tex]
Volume of solution = 2.7 L
Equilibrium concentration of [tex]Ni(CO)_4[/tex] = [tex]\frac{0.0035mol}{2.7L}=1.29\times 10^{-3}M[/tex]
Equilibrium concentration of [tex]Ni[/tex] = [tex]\frac{0.216mol}{2.7L}=0.08M[/tex]
Equilibrium concentration of [tex]CO[/tex] = [tex]\frac{0.071mol}{2.7L}=0.026M[/tex]
The given balanced equilibrium reaction is,
[tex]Ni(CO)_4\rightleftharpoons Ni+4CO[/tex]
The expression for equilibrium constant for this reaction will be,
[tex]K_c=\frac{[Ni]^1\times [CO]^4}{[Ni(CO_4]^1}[/tex]
Now put all the given values in this expression, we get :
[tex]K_c=\frac{(0.08)^1\times (0.026)^4}{(1.29\times 10^{-3})^1}[/tex]
[tex]K_c=2.8\times 10^{-5}[/tex]
Thus the value of the equilibrium constant for this reaction is [tex]2.8\times 10^{-5}[/tex]
Ammonium perchlorate is the solid rocket fuel used by the U.S. Space Shuttle. It reacts with itself to produce nitrogen gas , chlorine gas , oxygen gas , water , and a great deal of energy. What mass of water is produced by the reaction of of ammonium perchlorate? Be sure your answer has the correct number of significant digits.
Answer:
2.9 g of water are produced by 9.6 g of ammonium perchlorate
Note: The question is incomplete. The complete question is given below:
Ammonium perchlorate (NH₄ClO₄) is the solid rocket fuel used by the U.S. Space Shuttle. It reacts with itself to produce nitrogen gas (N₂) , chlorine gas (Cl₂), oxygen gas (O₂), water (H₂O) , and a great deal of energy. What mass of water is produced by the reaction of 9.6 g of ammonium perchlorate? Be sure your answer has the correct number of significant digits.
Explanation:
The reaction of ammonium perchlorate (NH₄ClO₄) to produce nitrogen gas (N₂) , chlorine gas (Cl₂), oxygen gas (O₂), water (H₂O) is shown in the balanced chemical equation given below:
2 NH₄ClO₄ → N₂ + Cl₂ + 2 O₂ + 4 H₂O
From the equation, 2 moles of ammonium perchlorate produces 4 moles of water, i.e. mole ratio of NH₄ClO₄ to H₂O = 2 : 4 = 1 : 2
molar mass of ammonium perchlorate, NH₄ClO₄ = (14 + 4 * 1 + 35.5 +16 * 4) = 117.5
molar mass of water, H₂O = (2 * 1 + 16) = 18.0 g
mass of water produced = moles of ammonium perchlorate * 2 * molar mass of water
moles of perchlorate = mass / molar mass = 9.6/117.5
mass of water produced = 9.6/117.5 * 2 * 18.0 g = 2.94 g of water
Therefore, 2.9 g of water are produced by 9.6 g of ammonium perchlorate
Put the following experimental steps for the Acid-Base Equilibria (HCL and NaOH) in the correct order:
a. Perform a scout colorimetric titration. of diluted vinegar with NaOH.
b. One pair performs a careful colorimetric titration of diluted vinegar with NaOH and the other pair performs a potentiometic titration of diluted vinegar with NaOH.
c. Perform a scout colorimetric titration of HCl with NaOH.
d. One pair performs a careful colorimetric titration of HCl with NaOH and the other pair performs a potentiometic titration of HCl with NaOH.
e. Dilute a solution of commercial vinegar to prepare it for titration.
Answer:
e. Dilute a solution of commercial vinegar to prepare it for titration.
a. Perform a scout colorimetric titration of diluted vinegar with NaOH.
b. One pair performs a careful colorimetric titration of diluted vinegar with NaOH and the other pair performs a potentiometric titration of diluted vinegar with NaOH.
c. Perform a scout colorimetric titration of HCL with NaOH.
d. One pair performs a careful colorimetric titration of HCL with NaOH and the other pair performs a potentiometric titration of HCL with NaOH.
Explanation:
Titration is a process in which acid and base are introduced together to determine unknown concentration of acid or base. This is also known as neutralization reaction. The chemical process form salt and water as by products because acid molecules react with base molecules.
The experimental steps for the Acid-Base Equilibria in the correct order is e, a, b, c and d.
What is titration?Titration is a process in which we determine the concentration of any unknown acid and base by titrating them with the standard known concentration of base or acid.
In potentiometric titration, in the place of indicator potential difference is used across the analyte of electrolytic solution. And in colorimetric titration, absorbance of light is measured by the solution. Process of method which is involved in the titration is:
e. Dilute a solution of commercial vinegar to prepare it for titration.
a. Perform a scout colorimetric titration of diluted vinegar with NaOH.
b. One pair performs a careful colorimetric titration of diluted vinegar with NaOH and the other pair performs a potentiometric titration of diluted vinegar with NaOH.
c. Perform a scout colorimetric titration of HCL with NaOH.
d. One pair performs a careful colorimetric titration of HCL with NaOH and the other pair performs a potentiometric titration of HCL with NaOH.
Hence correct sequence is e, a, b, c and d.
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