Question 1

Which of the following best describes a substance that can be separated by physical means into two different liquids, but those liquids cannot be separated further by physical means?

Accepted Answer

A mixture

Question 2

Given the following isotopic data, calculate the average atomic mass. Show your work using the formula:

$$	ext{Average atomic mass} = (	ext{mass}_1 	imes 	ext{abundance}_1) + (	ext{mass}_2 	imes 	ext{abundance}_2)$$

Isotope A: 12.7396 amu (25.000%)
Isotope B: 11.3338 amu (75.000%)

Which of the following is the correct average atomic mass (rounded to 5 significant figures)?

Accepted Answer

11.685

Question 3

A 53.2 g sample of phosphoric acid ($$\mathrm{H_3PO_4}) $$has a density of $$1.685\ \mathrm{g/mL}. $$What volume in mL does it occupy? Use the formula:

$$	ext{Volume} = \frac{	ext{Mass}}{	ext{Density}}$$

Accepted Answer

31.6 mL

Question 4

A urine sample has a mass of 96.05 g and a volume of 14.61 mL. What is its specific gravity? (Specific gravity is the ratio of the density of the sample to the density of water, $$1.00\ \mathrm{g/mL}$$.)

$$	ext{Specific gravity} = \frac{	ext{mass}}{	ext{volume}}$$

Accepted Answer

6.58

Question 5

Which of the following is an example of a chemical change?

Accepted Answer

Milk turns sour in a few days at room temperature

Question 6

How many neutrons are present in the isotope Iodine-127?

Accepted Answer

74

Question 7

A combination of sand, salt, and water is best classified as a:

Accepted Answer

Heterogeneous mixture

Question 8

Which of the following particles has approximately the same mass as a neutron?

Accepted Answer

A proton

Question 9

The modern periodic table is arranged according to which property?

Accepted Answer

Atomic number

Question 10

Identify the type of compound for $$\mathrm{$$AlCl_3$$}.$$

Accepted Answer

Ionic compound

Question 11

How many valence electrons does a neutral atom of radon (Rn) have?

Accepted Answer

8

Question 12

Cadmium is found in which block of the periodic table?

Accepted Answer

d-block

Question 13

What is the charge on a chloride ion ($$\mathrm{Cl^-}) $$when it forms an ion?

Accepted Answer

-1

Question 14

What is the charge on an iodide ion ($$\mathrm{I^-}) $$when it forms an ion?

Accepted Answer

-1

Question 15

Convert $$22.592\ \mathrm{K} to$$ $$^{\circ}\mathrm{F}. $$Use the formulas:

$$^{\circ}\mathrm{C} = ^{\circ}\mathrm{K} - 273.15$$

$$^{\circ}\mathrm{F} = $$(^{\circ}$$\mathrm{C} 	imes \frac{9}{5}) + 32$$

What is the answer (rounded to the nearest integer)?

Accepted Answer

-418

Question 16

Convert $$28.563^{\circ}$$\mathrm{F}$$ to $$^{\circ}\mathrm{C}$$. Use the formula:

$$^{\circ}\mathrm{C} = $$(^{\circ}$$\mathrm{F} - 32) 	imes \frac{5}{9}$$

What is the answer (rounded to the nearest integer)?

Accepted Answer

-2

Question 17

If a car has an EPA mileage rating of $$65.7$$ miles per gallon, what is this rating in kilometers per liter? Use the following conversions:

$$1\ \mathrm{mile} = 1.609\ \mathrm{km}$$

$$1\ \mathrm{gallon} = 4\ \mathrm{qt}$$

$$1\ \mathrm{L} = 1.06\ \mathrm{qt}$$

Accepted Answer

28.0 km/L

Question 18

Express a speed of $$8.7402\ \mathrm{mi/h} in$$ $$\mathrm{m/s}$$, given $$1\ \mathrm{mi} = 1.609\ \mathrm{km}. ($$Remember: $$1\ \mathrm{km} = 1000\ \mathrm{m}$$, $$1\ \mathrm{h} = 3600\ \mathrm{s}.)

$$What is the answer (rounded to 5 significant figures)?

Accepted Answer

3.9064

Question 19

Which of the following best describes the difference between a compound and a mixture?

Accepted Answer

A compound is made of two or more elements chemically combined, while a mixture is a physical blend of substances.

CHEM 111 Exam 2 Study Guidance

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