Q: A 39.0 g piece of aluminum metal has a volume of 14.4 cm³. What is the apparent weight of the piece when it is immersed in chloroform (density = 1.49 g/cm³)? Use $$F = mg$$ and the concept of buoyant force.

$$39.0\ \text{g} - (14.4\ \text{cm}^3 \times 1.49\ \text{g/cm}^3) = 17.56\ \text{g}$$

Q: A small crystal of sucrose (C$$_{12}H$_{22}O$_{11}) $$has a mass of 5.345 mg and dimensions 2.20 mm × 1.36 mm × 1.12 mm. What is its density in g/mL?

$$\frac{5.345\ \text{mg}}{(2.20\ \text{mm} \times 1.36\ \text{mm} \times 1.12\ \text{mm})} = 1.60\ \text{g/mL}$$

Q: A piece of concrete weighs 120 N in air and 97 N when fully submerged in water. If the volume of water displaced is 4200 cm³, what is the density of the water? Use $$F = mg = \rho Vg$$ and $$g = 9.8\ \text{N/kg}.$$

$$\frac{23\ \text{N}}{4200\ \text{cm}^3 \times 9.8\ \text{N/kg}} = 0.00056\ \text{kg/cm}^3$$

Q: If a 0.02135 M aqueous solution is prepared at 21°C (density = 0.9979955 g/mL), what is the new concentration if the temperature increases to 26°C (density = 0.9967867 g/mL)? Use $$c' = c \frac{d'}{d}.$$

$$0.02135 \times \frac{0.9967867}{0.9979955} = 0.02131\ \text{M}$$

Question 1

Which color on the NFPA chemical hazard diamond indicates the level of fire hazard for a chemical?

Accepted Answer

Red

Question 2

A scientist needs to measure exactly 25.0 mL of a 0.100 M HCl solution to add to a 0.200 M NaOH solution. Which instrument should be used for the most accurate measurement?

Accepted Answer

Transfer pipet

Question 3

A 39.0 g piece of aluminum metal has a volume of 14.4 cm³. What is the apparent weight of the piece when it is immersed in chloroform (density = 1.49 g/cm³)? Use $$F = mg$$ and the concept of buoyant force.

Accepted Answer

$$39.0\ 	ext{g} - (14.4\ 	ext{cm}^3 	imes 1.49\ 	ext{g/cm}^3) = 17.56\ 	ext{g}$$

Question 4

Which of the following best describes the process of filtration in analytical chemistry?

Accepted Answer

Separation of a solid from a liquid by passing the mixture through a filter

Question 5

A small crystal of sucrose (C$$_{12}H$_{22}O$_{11}) $$has a mass of 5.345 mg and dimensions 2.20 mm × 1.36 mm × 1.12 mm. What is its density in g/mL?

Accepted Answer

$$\frac{5.345\ 	ext{mg}}{(2.20\ 	ext{mm} 	imes 1.36\ 	ext{mm} 	imes 1.12\ 	ext{mm})} = 1.60\ 	ext{g/mL}$$

Question 6

Which laboratory apparatus is best suited for evaporating a solvent to dryness?

Accepted Answer

Evaporating dish

Question 7

A piece of concrete weighs 120 N in air and 97 N when fully submerged in water. If the volume of water displaced is 4200 cm³, what is the density of the water? Use $$F = mg = ho Vg$$ and $$g = 9.8\ 	ext{N/kg}.$$

Accepted Answer

$$\frac{23\ 	ext{N}}{4200\ 	ext{cm}^3 	imes 9.8\ 	ext{N/kg}} = 0.00056\ 	ext{kg/cm}^3$$

Question 8

Which of the following is the correct formula for calculating the true mass $$m of an $$object, accounting for buoyancy in air?

Accepted Answer

$$m = m' \left(1 - \frac{d_a}{d_w}\right) \left(1 - \frac{d_a}{d}\right)$$

Question 9

If a 0.02135 M aqueous solution is prepared at 21°C (density = 0.9979955 g/mL), what is the new concentration if the temperature increases to 26°C (density = 0.9967867 g/mL)? Use $$c' = c \frac{d'}{d}.$$

Accepted Answer

$$0.02135 	imes \frac{0.9967867}{0.9979955} = 0.02131\ 	ext{M}$$

Question 10

Which of the following best describes the effect of increasing temperature on the molarity of a solution?

Accepted Answer

Molarity decreases because the volume expands.

Question 11

A scientist mixes 100 mL of 0.75 M KCl with 200 mL of pure water. What is the final molarity of KCl?

Accepted Answer

0.25 M

Question 12

Which laboratory apparatus is best used for grinding solid chemicals into a fine powder?

Accepted Answer

Mortar and pestle

Question 13

Which of the following is the correct definition of buoyant force?

Accepted Answer

The upward force exerted on an object in a fluid, equal to the weight of the fluid displaced

Question 14

Which of the following best describes the process of evaporation in mixture separation?

Accepted Answer

Separation of a solvent from a solute based on boiling point

Question 15

A scientist wants to achieve a 100-fold dilution. Which of the following is the correct way to do this?

Accepted Answer

99 parts solvent to 1 part solution

Question 16

Which of the following is NOT a required component of a chemical hazard label according to OSHA guidelines?

Accepted Answer

Manufacturer's logo

Question 17

A container weighs 73.190 g when empty and 87.308 g when filled with an unknown liquid. When filled with water, the mass is 88.442 g (density of water at 19°C = 1.0027 g/mL). What is the density of the unknown liquid?

Accepted Answer

$$\frac{87.308 - 73.190}{88.442 - 73.190} 	imes 1.0027 = 0.972\ 	ext{g/mL}$$

Analytical Chemistry: Tools of the Trade – Safety, Measurement, and Laboratory Techniques

Study Guide - Practice Questions

Study Guide - Flashcards