A student masses a green crystal sample and records 1.253 grams. He then dissolves the green crystal in water and does a titration, and calculates that his sample has 7.35x10-3 moles of C2O4-2.
What is the percent of C2O4-2 in the sample?
a. not enough information is given
b. 51.63%
c. 129%
d. 0.5866%
e. 20.62%
Answer:
b. 51.63%
Explanation:
Step 1: Given data
Mass of the sample: 1.253 gMoles of oxalate (C₂O₄²⁻): 7.35 × 10⁻³ molStep 2: Calculate the mass corresponding to 7.35 × 10⁻³ moles of oxalate
The molar mass of C₂O₄²⁻ is 88.02 g/mol.
7.35 × 10⁻³ mol × 88.02 g/mol = 0.647 g
Step 3: Calculate the mass percent of oxalate in the sample
% w/w = mass of oxalate / mass of the sample × 100%
% w/w = 0.647 g / 1.253 g × 100%
% w/w = 51.63%
If 8.2 mL of 0.055 M NaOH is required to titrate a 5.5 mL sample of potassium bitartrate, what is the [K +]?
Answer:
.082 M
Explanation:
You just do C1V1=C2V2
The concentration of the potassium bitartrate acid is determined as 0.082 M.
Concentration of the acidThe concentration of the potassium bitartrate acid is calculated as follows;
C1V1 = C2V2
where;
C1 is the concentration of the base = 0.055V1 is the volume of the base = 8.2 mlC2 is the concentration of the acidV2 is the volume of the acid = 5.5 mlC2 = (C1V1)/(V2)
C2 = (0.055 x 8.2)/(5.5)
C2 = 0.082
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pretty please help me (:
Okay I need an explanation from YOU. when is this due? If it’s last minute, why didn’t you do it when you had time? This is very irresponsible, unless you have a personal reason. Please quit commenting on others just for the points. I helped you with one, because I thought it was just one question you needed help with. No one is going to finish this for you. I’m sorry but it’s the truth, everyone here needs help. No one is here TO help. So please be cooperative and try to learn. Of course, I’m sorry if it is for a very personal reason as it happens to everyone where you need the work ASAP because of a reason. Hopefully, it’s not because you were lazy. Appreciate your education as not many people in the world have it.
If 17.8 g grams of lithium (Li) are combined with 50.0 grams of water (H20) there is
24.7 grams of hydrogen gas (H2) produced. How much lithium hydroxide (LiOH) was
also produced?
Answer:
Explanation:
Li+H2O..................LiOH+H2
mass of Li=17.8 g
No of moles of Li=17.8/7=2.5
mass of H2O=50.0 g
No of moles of H2O=50.0/18=2.8
limiting reagent is Li so 1 mole of Li produce 1 mole of LiOH therefore 2.5 mole of Li produce 2.5 moles of LiOH now we have to convert it into grams
moles=given mass/molar mass
given mass=moles*molar mass
molar mass of LiOH=24
mass=2.5*24=60 gram
How many atoms of hydrogen would need to bond with a single atom of selenium to form a molecular compound?
Answer:
Hydrogen sulfide reacts with aqueous selenous acid to produce selenium disulfide:
H2SeO3 + 2 H2S → SeS2 + 3 H2O
Selenium disulfide consists of 8-membered rings. It has an approximate composition of SeS2, with individual rings varying in composition, such as Se4S4 and Se2S6. Selenium disulfide has been used in shampoo as an antidandruff agent, an inhibitor in polymer chemistry, a glass dye, and a reducing agent in fireworks.[15]
Selenium trioxide may be synthesized by dehydrating selenic acid, H2SeO4, which is itself produced by the oxidation of selenium dioxide with hydrogen peroxide:[17]
SeO2 + H2O2 → H2SeO4
Hot, concentrated selenic acid can react with gold to form gold(III) selenate.[18]
How often waves repeat is called their
Answer:
Wave Frequency
.What is the effective number of bonds between the sulfur atom and each oxygen atom in the sulfate ion
Answer:
The effective number of bonds in sulfate ion is 1.5
Explanation:
The number of chemical bonds between two atoms is known as the bond order.
In covalent bonds between two atoms, a single bond has a bond order of one, a double bond has a bond order of two, a triple bond has a bond order of three.
If there are more than two atoms in a molecule, the effective number of bonds can be determined by applying the following steps:
1. Draw the Lewis structure.
2. Count the total number of bonds.
3. Count the number of bond groups between individual atoms.
4. Divide the number of bonds between atoms by the total number of bond groups in the molecule.
For the sulfate ion, the resonance structure is shown in the attachment below. From the structure;
Total number of bonds = (2 × 2) + (2 × 1) = 6
Total number of bond groups = 4
Effective number of bonds = 6/4 = 1.5
Therefore, the effective number of bonds in sulfate ion is 1.5
Which of the following is an example of a physical change?
А.
sugar and oxygen reacting to produce water and carbon dioxide
B
honey dissolving in tea
С
a raw egg being cooked
D
metal rusting after being left out in the rain
Answer:
B. honey dissolving in tea
Explanation:
What may form when magma comes to the surface?
Answer
When magma reaches the surface it is called lava. After lava has cooled it forms solid rock.
Answer:
Volcano
Explanation:
when magma reaches the surface it cools and then magma will start coming out over and over and over again. Then we have a volcano. hopemthis helps
One mole of an ideal gas expands reversibly and isothermally from 10. bar to 1.0 bar at 298.15K.
Required:
a. Calculate the values of w, q, âU and âH?
b. Calculate w if the gas were to have expanded to the same final state against a constant pressure of 1 bar.
Answer:
a. W = 5,708 J, Q = 5,708 J, ΔU = 0 and ΔH = 0.
b. 2,231 J.
Explanation:
Hello!
a. In this case, since this is an isothermal process (constant temperature) it is possible to infer that the work is computed as shown below:
[tex]W=nRTln(\frac{p_1}{p_2} )=1mol*8.314\frac{J}{mol*K}*298.15Kln(\frac{10.bar}{1.0bar} )\\\\W=5708J[/tex]
Now, since this is an isothermal process we know by definition ΔU = 0 and ΔH = 0, therefore the involved heat is:
[tex]Q-W=0\\\\Q=W=5708J[/tex]
b. In this case, since the process is isobaric but goes to the same final volume in part a, we can compute the initial and final volume based on the part a's conditions by using the ideal gas equation:
[tex]V_1=\frac{nRT}{p_1} =\frac{1mol*0.083145\frac{*L}{mol*K}*298.15K}{10.bar} =2.48L\\\\V_2=\frac{nRT}{p_2} =\frac{1mol*0.083145\frac{*L}{mol*K}*298.15K}{1.bar} =24.8L[/tex]
Thus, the work done here is:
[tex]W=p(V_2-V_1)=1bar(24.8L-2.48L)=22.3bar*L*\frac{1x10^5Pa}{1bar} *\frac{1m^3}{1000L} \\\\W=2231J[/tex]
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13. As heat is added to a lúguid that is boiling at constant
pressure, the temperature of the liquid
A) decreases B) increases
C) remains the same
A
B
Pleaseeee help I’m stuck on this problem
What is the mole fraction of KCI in a
mixture of 0.564 g NaCl, 1.52 g KCI,
and 0.857 g LICI?
Answer:
0.4
Explanation:
Given parameters:
Mass of NaCl = 0.564g
Mass of KCl = 1.52g
Mass of LiCl = 0.857g
Unknown:
Mole fraction of KCl = ?
Solution:
First, find the number of moles of the given species;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of KCl = 39 + 35.5 = 74.5g/mol
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Molar mass of LiCl = 7 + 35.5 = 42.5g/mol
Number of moles of KCl = [tex]\frac{1.52}{74.5}[/tex] = 0.02mol
Number of moles of NaCl = [tex]\frac{0.564}{58.5}[/tex] = 0.0096mol
Number of moles of LiCl = [tex]\frac{0.857}{42.5}[/tex] = 0.02mol
Sum of moles = 0.02mol + 0.0096mol + 0.02mol = 0.0496mol
Mole fraction of KCl = [tex]\frac{0.02}{0.0496}[/tex] = 0.4
Answer:
.4
Explanation:
A 50.0 mL sample of HCl required 25.81 mL of 0.1250 M KOH for neutralization. What is the molarity of the acid?
Answer:
0.065M
Explanation:
The reaction expression is given as:
HCl + KOH → KCl + H₂O
Given parameters:
Volume of KOH = 25.81mL = 0.02581L
Molarity of KOH = 0.125M
Volume of HCl = 50mL = 0.05L
Unknown:
Molarity of the acid = ?
Solution:
To find the molarity of the acid, HCl, let us use the mole concept.
First, find the number of moles of the base, KOH;
Number of moles of KOH = molarity of KOH x volume of KOH
Number of moles of KOH = 0.125 x 0.0258 = 0.003225mol
From the balanced reaction equation:
1 mole of KOH reacted with 1 mole of HCl
0.003225mol of KOH will react with 0.003255mole of HCl
Molarity of HCl = [tex]\frac{number of moles of HCl}{Volume of HCl}[/tex]
Molarity of HCl = [tex]\frac{0.003255}{0.05}[/tex] = 0.065M
A 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate (KHP, formula mass = 204.22 g/mol) is diluted to 250.0 mL. What is the molarity of the final solution?
Answer:
[KHP] = 0.0428M
Explanation:
2 methods to calculate concentration after dilution
1. Use dilution equation
Molarity of concentrate (M₁) x Volume of Concentrate (V₁)
= Molarity of dilute (M₂) x Volume of dilute (V₂)
M₁ x V₁ = M₂ x V₂ => M₂ = M₁ x V₁ / V₂ = (1.07M)(10ml)/(250ml) = 0.0428M
2. Concentration Equation
moles KHPh = Molarity (M) x Volume (V) = 1.07M x 0.010L =0.0107 moles KHP
Concentration KHP = moles solute / volume of solution in Liters
= 0.0107 moles KHP / 0.25L = 0.0428M
The molarity of 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate diluted to 250.0mL is 0.0428M.
HOW TO CALCULATE MOLARITY:
The molarity of a diluted solution can be calculated by using the following formula:C1V1 = C2V2
Where;
C1 = initial concentration of solutionC2 = final concentration of solutionV1 = initial volume of solutionV2 = final volume of solutionAccording to this question,
C1 = 1.07MC2 = ?V1 = 10.0mLV2 = 250mL1.07 × 10 = C2 × 25010.7 = 250C2C2 = 10.7 ÷ 250C2 = 0.0428MTherefore, the molarity of 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate diluted to 250.0mL is 0.0428M.Learn more about how to calculate molarity of a solution at: https://brainly.com/question/13386686?referrer=searchResults
Calculate the amount of grams of water that was used when 5525J of energy was used to boil this amount of water.
Answer:
2.445 g
Explanation:
Step 1: Given and required data
Energy in the form of heat required to boil the water (Q): 5525 JLatent heat of vaporization of water (∆H°vap): 2260 J/gMass of water (m): ?Step 2: Calculate the mass of water
We will use the following expression.
Q = ∆H°vap × m
m = Q / ∆H°vap
m = 5525 J / (2260 J/g)
m = 2.445 g
Convert from 1.56×1030 particles of sodium chloride (NaCl) to grams of sodium chloride.
Answer:
15.14×10⁷ g
Explanation:
Given data:
Number of particles of NaCl = 1.56×10³⁰ particles
Mass of sodium chloride = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ particles
1.56×10³⁰ particles × 1 mol / 6.022 × 10²³ particles
0.259 ×10⁷ mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 0.259 ×10⁷ mol × 58.44 g/mol
Mass = 15.14×10⁷ g
How many grams of KOH are required to prepare 500. mL of 0.450 KOH solution?
Answer:
KOH molar mass = 39 + 16 + 1 = 56g
To make 1 L of 1M soln needs 56g KOH
To make 500mL 1M needs 56/2 = 28g
To make 500mL 0.2M needs 28 x 0.2gn:
What is the main goal of cloning? A. To make living things that have identical DNA
B. To improve the process of asexual reproduction
C. To add medicines to the foods that people eat
D. To spread genes from transgenic plants to wild plants
Answer:
A
Explanation:
A p e x
A covalent bond is formed by:
loss of electrons between atoms
sharing of electrons between atoms
gain of electrons between atoms
valence electron shells overlaping, forming a "sea of electrons"
Answer:
sharing of electrons between atoms
Question 2
The higher the energy, the higher or lower the wavelength? This is an example of a/an direct or inverse relationship?
Answer:
the higher the energy tje lower the wavelength
Explanation:
inverse relationship
Answer:
It's an example of an inverse relationship :)
How much energy, in kilojoules, must you add to 3.00 quarts of olive oil to warm it from 23.0 °C to 100.0 °C? The specific heat of olive oil is 0.1.79 J/g·°C and its density is 0.916 g/mL
Answer:
3.58*10^-4kJ
Explanation:
Given
T1=23.0 °C
T2=100.0 °C
c=1.79 J/g·°C
Volume of olive =3 quarts
Converting to liter
1 quart =0.946353 L
3 quarts=x
Cross multiplying
x=0.946353*3
x=2.83L
To mL= 0.0028mL
We are given the density as 0.916 g/mL
Mass= density *volume
Mass= 0.916*0.0028
Mass=0.0026g
We know that the quantity of heat is expressed as
Q=mcΔT
Q=0.0026*1.79(23-100)
Q=0.004654*(77)
Q=0.358J
In kJ we divide 0.36 by 1000
=0.000358358
=3.58*10^-4kJ
Which substance has the most thermal energy and will have the most heat flow from it?
A. a stovetop burner on medium (200°C)
B. a nuclear reactor core (1000°C)
C. the human body (36°C)
D. air at room temperature (32°C)
Answer:
B. a nuclear reactor core (1000°C)......
What is percent error calculation used to determine
IMESSAGE GAMES ANYONE?
Answer:
oop whats dis
Explanation:
The reference point in motion is:
A. The point in space and time at which the motion ended
B. The point in space and time at which the motion began
C. The focal point
D. The origin
Answer: the focal point
Question 1 Give the correct number of significant figures for 4500, 4500., 0.0032, 0.04050
Question 2 Give the answer to the correct number of significant figures:
4503 + 34.90 + 550 = ?
the correct number of significant figures.
uction 2 Give
Answer:
Question 2
5087.9 or 5088
Which property (volume , mass , or density) is a measure of the space it takes up?
Answer:
mass
Explanation:
If a liquid is said to have high viscosity it is...
Answer:
Viscosity is the measure of resistance of a fluid to flow. A fluid that is highly viscous has a high resistance (like having more friction) and flows slower than a low-viscosity fluid. To think of viscosity in everyday terms, the easier a fluid moves, the lower the viscosity
Explanation:
What is the reason for the trend in Atomic Radii? Select all that apply.
A. number of valence electrons.
B. number of neutrons in the nucleus
C. number of protons in the nucleus
D. larger atomic mass number
E. number of energy levels around the nucleus
What is the balanced NET ionic equation for the reaction when aqueous Cs₃PO₄ and aqueous AgNO₃ are mixed in solution to form solid Ag₃PO₄ and aqueous CsNO₃
Answer:
[tex]PO_4^{3-}(aq)+3Ag^+(aq)\rightarrow Ag_3PO_4(s)[/tex]
Explanation:
Hello!
In this case, since the net ionic equation of a chemical reaction shows up the ionic species that result from the simplification of the spectator ions, which are those at both reactants and products sides, we take into account that aqueous species ionize into ions whereas liquid, solid and gas species remain unionized. In such a way, for the reaction of cesium phosphate and silver nitrate we can write the complete molecular equation:
[tex]Cs_3PO_4(aq)+3AgNO_3(aq)\rightarrow Ag_3PO_4(s)+3CsNO_3(aq)[/tex]
Whereas the three aqueous salts are ionized in order to write the following complete ionic equation:
[tex]3Cs^+(aq)+PO_4^{3-}(aq)+3Ag^+(aq)+3NO_3^-(aq)\rightarrow Ag_3PO_4(s)+3Cs^+(aq)+3NO_3^-(aq)[/tex]
In such a way, since the cesium and nitrate ions are the spectator ions because of the aforementioned, the net ionic equation turns out:
[tex]PO_4^{3-}(aq)+3Ag^+(aq)\rightarrow Ag_3PO_4(s)[/tex]
Best regards!