Question 1

Which of the following best describes the difference between a homogeneous and a heterogeneous mixture? Give an example of each.

Accepted Answer

A homogeneous mixture is uniform throughout, such as saltwater; a heterogeneous mixture has visibly different parts, such as salad.

Question 2

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

Accepted Answer

Burning wood

Question 3

How many significant figures are in the measurement $$0.003050$$?

Accepted Answer

$$4$$

Question 4

Convert $$12.56$$ inches to centimeters. (Recall that $$1$$ inch $$= 2.54 cm.)$$

Accepted Answer

$$31.90 cm$$

Question 5

A sample contains $$77.0\%$$ carbon, $$6.43\%$$ hydrogen, and the rest is oxygen. The molar mass of the substance is $$302.0 g/$$mol. What is its molecular formula?

Accepted Answer

$$C_{16}H$$_{16}$$O_{4}$

Question 6

Which scientist is credited with discovering the electron?

Accepted Answer

Thomson

Question 7

How many protons, neutrons, and electrons are in an atom of $$^{40}_{18}Ar$$?

Accepted Answer

18 protons, 22 neutrons, 18 electrons

Question 8

What is the correct formula for the compound formed by aluminum and fluorine?

Accepted Answer

$$AlF_3$$

Question 9

Which of the following is the balanced equation for the double replacement reaction of potassium hydroxide with sulfuric acid?

Accepted Answer

$$2KOH + H_2SO_4 \rightarrow K_2SO_4 + 2H_2O$$

Question 10

What is the percent yield if $$18.4 g of$$ $$C_6H_6$$ reacts with excess $$Cl_2 to $$produce $$15.4 g of$$ $$C_6H_5Cl$$? (Molar masses: $$C_6H_6 = 78.1 g/$$mol, $$C_6H_5Cl = 112.6 g/$$mol)

Accepted Answer

$$84.0\%$$

Question 11

A sealed balloon is filled with $$1.00 L $$helium at $$25^\circ C$$ and $$1.00$$ atm. The balloon rises to a point where the pressure is $$0.800$$ atm and the temperature is $$-31^\circ C. $$What is the change in volume of the balloon as it ascends?

Accepted Answer

$$1.36 L$$

Question 12

Which of the following is a decomposition reaction?

Accepted Answer

$$2H_2O_2 \rightarrow 2H_2O + O_2$

Question 13

What is the percent by mass of oxygen in $$Fe_2O_3$$?

Accepted Answer

$$30.06\%$$

Question 14

Calculate the grams of carbon dioxide produced when a mixture of $$21.8 g of $$carbon disulfide and $$13.1 g of $$oxygen reacts. (Given: $$CS_2 + 3O_2$$ \rightarrow $$CO_2 + 2SO_2$)

Accepted Answer

$$8.03 g$$

Question 15

Which of the following is the correct name for $$Na_2CO_3$$?

Accepted Answer

Sodium carbonate

Question 16

What is the major source of barium hydroxide and potassium permanganate?

Accepted Answer

Barium ore and manganese ore

Question 17

How many atoms of hydrogen are there in $$C_2H_4O_2$$?

Accepted Answer

$$4$$

Question 18

Which of the following is the correct formula for magnesium acetate?

Accepted Answer

$$Mg(C_2H_3O_2)_2$$

Question 19

What is the oxidation state of chromium in $$Cr_2O_7$$^{2-}$$?

Accepted Answer

$$+6$$

Question 20

A person accidentally swallows a drop of liquid oxygen ($$O_2$$), which has a density of $$1.14 g/mL. $$Assuming the drop has a volume of $$0.050 mL$$, what volume of gas ($$O_2) $$will be produced in the person's stomach at body temperature ($$37^\circ C) $$and pressure ($$1.00$$ atm)?

Accepted Answer

$$0.042 L$$

General Chemistry Midterm Review: Key Concepts and Practice Problems

Study Guide - Practice Questions

Study Guide - Flashcards