1-\Naturally occurring copper exists in two isotopic forms:⁶³Cu and⁶⁵Cu. The atomic mass of copper is63.55 amu. What is the approximate natural abundance of⁶³Cu?​

Select one:

a.

​63%

b.

​90%

c.

​70%

d.

​30%

e.

​50%

1-\The molar mass of the compound formed by potassium and sulfuris _____.  

Select one:

a.

​110.3 g/mol

b.

​135.3 g/mol

c.

​103.2 g/mol

d.

​71.2 g/mol

e.

​149.4 g/mol

How many oxygen atoms are there in one formula unit ofCa₃(PO₄)₂?

Select one:

a.

​none of these

b.

​2

c.

​4

d.

​6

e.

​8

​What is the molar mass of ethanol(C₂H₅OH)?

Select one:

a.

​34.06 g/mol

b.

​46.07 g/mol

c.

​105.03 g/mol

d.

​45.06 g/mol

e.

​30.03 g/mol

How many oxygen atoms are there in 3 formula units ofAl(NO₃)₃?

Select one:

a.

​15

b.

​9

c.

​30

d.

​27

e.

​14

The molar mass of an insecticide, dibromoethane, is 187.9 g/mol.Its molecular formula is C₂H₄Br₂.What percent by mass of carbon does dibromoethane contain?

Select one:

a.

2.14%

b.

85.05%

c.

6.39%

d.

12.78%

e.

0.536%

​What is the molar mass of cryolite(Na₃AlF₆)?

Select one:

a.

​185.3 g/mol

b.

​104.2 g/mol

c.

​210.0 g/mol

d.

​209.9 g/mol

e.

​68.97 g/mol

Each molecule of lycopene contains 40 atoms of carbon (plusother atoms). The mass percent of carbon in lycopene is 84.49%.What is the molar mass of lycopene?

Select one:

a.

1137.2 g/mol

b.

568.6 g/mol

c.

480.4 g/mol

d.

405.9 g/mol

e.

473.4 g/mol

​Calculate the molar mass of magnesium sulfite.

Select one:

a.

​288.83 g/mol

b.

​120.38 g/mol

c.

​104.38 g/mol

d.

​128.69 g/mol

e.

​88.38 g/mol

How many atoms of hydrogen are present in 6.43 g of ammonia?

Select one:

a.

​2.27 × 10²³

b.

​9.41 × 10¹⁹

c.

​1.16 × 10²⁵

d.

​6.82 × 10²³

e.

​1.28 × 10²⁴

​A given sample of a xenon fluoride compound contains moleculesof a single type XeF_n, where n is somewhole number. Given that 8.86 × 10²⁰ molecules ofXeF_n weigh 0.361 g, calculate n.

Select one:

a.

​3

b.

​2

c.

​1

d.

​6

e.

​4

What would be the g Al / mole S ratio for the product of areaction between aluminum and sulfur?

Select one:

a.

53.96 g Al / mol S

b.

17.99 g Al / mol S

c.

26.98 g Al / mol S

d.

40.47 g Al / mol S

e.

80.94 g Al / mol S

How many grams of potassium are in 15.0 g ofK₂CrO₇?

Select one:

a.

4.84 g

b.

2.42 g

c.

30.0 g

d.

78.2 g

e.

0.767 g

​How many moles of hydrogen sulfide are contained in a 39.3-gsample of this gas?

Select one:

a.

​19.5 mol

b.

​2.31 mol

c.

​0.867 mol

d.

​1.15 mol

e.

​73.4 mol

Nitric acid, HNO₃, contains what percent hydrogen bymass?

Select one:

a.

2.22%

b.

3.25%

c.

20.0%

d.

1.60%

e.

25.4%

The mineral mimetite has the formulaPb₅(AsO₄)₃Cl. What mass percent ofoxygen does it contain?

Select one:

a.

12.90 %

b.

38.70 %

c.

50.32 %

d.

1.08 %

e.

16.34 %

Which compound contains the highest percent by mass ofhydrogen?

Select one:

a.

H₂SO₄

b.

HF

c.

H₂S

d.

H₂O

e.

HCl

A hydrocarbon (a compound consisting solely of carbon andhydrogen) is found to be 85.6% carbon by mass. What is theempirical formula for this compound?

Select one:

a.

C₃H

b.

CH₄

c.

CH

d.

C₂H

e.

CH₂

Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass.What is the empirical formula?

Select one:

a.

C₃HO₃

b.

C₃H₃O₄

c.

C₂H₅O₄

d.

C₂HO₃

e.

C₃H₅O₂

The empirical formula of a group of compounds is CHCl. Lindane,a powerful insecticide, is a member of this group. The molar massof lindane is 290.8 g/mol. How many atoms of carbon does a moleculeof lindane contain?

Select one:

a.

3

b.

8

c.

4

d.

6

e.

2

The empirical formula of styrene is CH; its molar mass is 104.1g/mol. What is the molecular formula of styrene?

Select one:

a.

C₈H₈

b.

C₆H₆

c.

C₁₀H₁₂

d.

C₂H₄

e.

none of these

A reaction occurs between sodium carbonate and hydrochloric acidproducing sodium chloride, carbon dioxide, and water. The correctset of coefficients, respectively, for the balanced reactionis:

Select one:

a.

8 6 5 10 5

b.

3 6 6 3 4

c.

none of these

d.

1 2 2 1 1

e.

5 10 10 5 5

Which of the following equations correctly describes thecombustion of CH₄ and O₂ to produce water(H₂O) and carbon dioxide (CO₂)?

Select one:

a.

CH₄ + O₂ → CO₂ +H₂O

b.

CH₄ + 2O₂ → CO₂ +2H₂O

c.

2CH₄ + 3O₂ → 2CO₂ +2H₂O

d.

CH₄ + O₂ → CO₂ +2H₂O

e.

CH₄ + 3O₂ → 2CO₂ +H₂O

Give (in order) the correct coefficients to balance thefollowing reaction:
H₂SnCl₆ + H₂S → SnS₂ +HCl

Select one:

a.

6, 2, 1, 1

b.

1, 1, 1, 6

c.

1, 2, 1, 6

d.

1, 2, 2, 2

e.

2, 4, 2, 6

​How many of the following are true concerning balanced chemicalequations?

I.   The number of molecules is conserved.

II. The coefficients for the reactants tell you how much of eachreactant you are given.

III. Atoms are neither created nor destroyed.

IV. The coefficients indicate the mass ratios of the substancesused.

V.   The sum of the coefficients on the reactant sideequals the sum of the coefficients on the product side.

Select one:

a.

​3

b.

​1

c.

​2

d.

​4

e.

​5