Q: Which of the following is the correct empirical formula for a compound that is 62.0% C, 10.4% H, and 27.5% O by mass?

$$\text{C}_3\text{H}_6\text{O}$$

Q: Which of the following is NOT an empirical formula?

$$\text{C}_2\text{H}_4\text{O}_2$$

Q: Which of the following sets contains species with the same number of electrons?

$$\text{F}^-,\ \text{Ne},\ \text{Mg}^{2+}$$

Q: A hospital uses $$7.59\ \text{L} of $$saline solution. How many milliliters is this?

$$7.59 \times 10^3$\ \text{mL}$$

Question 1

Which of the following substances is an ionic compound commonly used in medical saline solutions, and what is the primary type of chemical bond present in it?

Accepted Answer

NaBr; ionic bonds

Question 2

A patient receives 300 g of potassium as part of a treatment. How many moles of potassium does this represent? (Atomic mass of potassium = $$39.10\ 	ext{g/mol})$$

Accepted Answer

$$7.67\ 	ext{moles}$$

Question 3

Which of the following is a chemical change that occurs in everyday life, and why?

Accepted Answer

A candle burns; because it produces new substances like CO2 and H2O

Question 4

A sample contains $$2.16 	imes 10$$^{24}$$ atoms of silver. How many moles of silver are present? (Avogadro's number = 6.022$$ 	imes $$10^{23})$$

Accepted Answer

$$3.59\ 	ext{moles}$$

Question 5

Which of the following is the correct empirical formula for a compound that is 62.0% C, 10.4% H, and 27.5% O by mass?

Accepted Answer

$$	ext{C}_3	ext{H}_6	ext{O}$$

Question 6

A 43.6 g piece of metal has a density of $$2.71\ 	ext{g/cm}^3. $$What is its volume in $$	ext{cm}^3$$?

Accepted Answer

$$16.1\ 	ext{cm}^3$$

Question 7

Which of the following is a polyatomic molecule, and what is its chemical formula?

Accepted Answer

Phosphorus; $$	ext{P}_4$$

Question 8

A combustion analysis of a compound containing only carbon and hydrogen produced $$0.2845\ 	ext{g} of$$ $$	ext{CO}_2$$ and $$0.1451\ 	ext{g} of$$ $$	ext{H}_2	ext{O}. $$What is the empirical formula of the compound?

Accepted Answer

$$	ext{C}_2	ext{H}_5$$

Question 9

Which of the following is the smallest volume?

Accepted Answer

$$22\ 	ext{cm}^3$$

Question 10

A person weighs $$77.1\ 	ext{kg}. $$What is their weight in pounds? (1 kg $$= 2.20462$$ pounds)

Accepted Answer

$$170\ 	ext{pounds}$$

Question 11

Which of the following is NOT an empirical formula?

Accepted Answer

$$	ext{C}_2	ext{H}_4	ext{O}_2$$

Question 12

What is the correct chemical formula for barium nitrite?

Accepted Answer

$$	ext{Ba(NO}_2)_2$$

Question 13

How many electrons does the $$	ext{Al}^{3+}$$ ion possess?

Accepted Answer

10

Question 14

Which of the following sets contains species with the same number of electrons?

Accepted Answer

$$	ext{F}^-,\ 	ext{Ne},\ 	ext{Mg}^{2+}$$

Question 15

A hospital uses $$7.59\ 	ext{L} of $$saline solution. How many milliliters is this?

Accepted Answer

$$7.59 	imes 10^3$\ 	ext{mL}$$

Question 16

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest, whole-number coefficients?

$$\_\_\_\_\ 	ext{C}_2	ext{H}_6	ext{O} (l) + \_\_\_\_\ 	ext{O}_2(g) ightarrow \_\_\_\_\ 	ext{CO}_2(g) + \_\_\_\_\ 	ext{H}_2	ext{O}(l)$$

Accepted Answer

3

Question 17

A room measures $$11.0\ 	ext{ft} 	imes 11.0\ 	ext{ft}$$ with a $$10.0\ 	ext{ft}$$ ceiling. If the density of air at $$25^\circ	ext{C} is$$ $$1.19\ 	ext{g/L}$$, how many kilograms of air are in the room? ($$1\ 	ext{in} = 2.54\ 	ext{cm}$$, $$1\ 	ext{L} = 10^3$\ 	ext{cm}^3)$$

Accepted Answer

$$40.8\ 	ext{kg}$$

Question 18

Which of the following is a homogeneous mixture?

Accepted Answer

Cola

Question 19

A Halloween light stick glows after shaking. Which type of change is this, and why?

Accepted Answer

Chemical change; because new substances are formed and energy is released

General Chemistry Practice Exam 1 – Step-by-Step Study Guidance

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