A. Incorrect! Grams are a common unit for mass, but it is not the SI unit. Scale measures weight (which is gravity dependent), not mass.

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1 CLEP Chemistry - Problem Drill 24: Chemical Laboratory No. 1 of What is the correct SI unit for mass and what instrument is used to measure it? (A) Grams, scale (B) Grams, balance (C) Kilograms, scale (D) Kilograms, balance (E) Tons, scale Grams are a common unit for mass, but it is not the SI unit. Scale measures weight (which is gravity dependent), not mass. B. Incorrect! Grams are a common unit for mass, but it is not the SI unit. Scale measures weight (which is gravity dependent), not mass. D. Correct! Kilograms are the correct SI unit for mass and it is measured with a balance. Tons are a common unit for large weight, but it is not the SI unit. Scale measures weight (which is gravity dependent), not mass. Grams are a common unit for mass, but it is not the SI unit. Scale measures weight (which is gravity dependent), not mass. Kilograms are the correct SI unit for mass and it is measured with a balance. The correct answer is (D).

2 No. 2 of Distillation separates mixtures based on. (A) solubility (B) boiling point (C) freezing point (D) attraction to other stationary phase molecules (E) melting point Filtration separates based on solubility. B. Correct Distillation separates based on boiling point. Distillation used boiling point, no freezing point. Separating based on attraction to stationary phase molecules is chromatography. Distillation used boiling point, no melting point. Distillation separates based on boiling point. The correct answer is (B).

3 No. 3 of Take the following measurement to the correct number of decimal places. (A) 30 ml (B) 30.0 ml (C) ml (D) 3.0 ml (E) ml 30 ml has too few decimal places. B. Correct! It s on the 30 line, so add a 0 at the end to indicate it s on the line has too many decimal places. The arrow is on the 30 ml line, not the 3 ml line has too many decimal places. This measurement is on the 30 ml line. A final 0 is added when a measurement in on the line The correct answer is (B).

4 No. 4 of Titration is a technique to determine. (A) Boiling point of a liquid. (B) Concentration of a solution. (C) Density of a solution. (D) Energy transfers. (E) Molecular mass. Titration is used to find the concentration of a solution. B. Correct! Titration is used to find the concentration of a solution. Density is found by dividing mass by volume. Titration finds concentration. Calorimetry is used to determine energy transfers. Titration is not used for molecular mass determination. Titration is used to determine the concentration of a solution. The correct answer is (B).

5 No. 5 of What instrument is used to measure volumes? (A) Balance (B) Beaker (C) Graduated cylinder (D) Test tube (E) Dropper Balances measure mass. B. Incorrect! Beakers are not accurate enough to measure liquids. C. Correct! Graduated cylinders measure volumes. Test tubes do not measure liquids, they simply hold them. Dropper is a pipette to release a drop at a time, not for accurate volume measurement. Graduated cylinders measure volume. The correct answer is (C).

6 No. 6 of What technique would most easily separate sand from water? (A) filtration (B) distillation (C) chromatography (D) titration (E) crystallization A. Correct! Filtration separates undissolved particles, like sand, from the liquid they are in. B. Incorrect! Distillation separates based on boiling points. While the water could be boiled from the container, filtration would be easier. Chromatography separates solutions, not mixtures with a component that is undissolved. Titration determines the concentration of a solution. Crystallization is the formation of crystalline from solutions. Filtration is an easy way to separate undissolved particles. The correct answer is (A).

7 No. 7 of Which of the following is an important safety rule? (A) Always add water to acid. (B) Always add acid to water. (C) Never mix acid and water. (D) Shake well before mixing. (E) Heat the acid first before mixing. Adding water to a concentrated acid can cause it to splash the more concentrated acid onto you. B. Correct! When adding water to acid, if it splashes, it will be less concentrated than if you were adding water to a concentrated acid solution. You can dilute acids with water. You don t want to shake the acid as it is considered to be an unsafe practice. Gases might be generated from shaking. You don t want to heat the acid as it is considered to be an unsafe practice. Heating up the acid would be hazardous. When adding water to acid, if it splashes, it will be less concentrated than if you were adding water to a concentrated acid solution. The correct answer is (B).

8 No. 8 of 10 Instruction: (1) Read the problem statement and answer choices carefully (2) Work the problems on paper as 8. When using a graduated cylinder, you should. (A) Lift the cylinder to your eye level. (B) Bend down until it is at eye level. (C) Read it from above while it s on the table. (D) Read from the top. (E) Read from the bottom. Lifting the cylinder may cause it to be unlevel. B. Correct! Lifting the cylinder may cause it to be unlevel you should bend down to it. Reading it from above will produce inaccurate results. You should bend down until it is at eye level. You should bend down until it is at eye level. You should bend down to read a graduated cylinder at eye level. The correct answer is (B).

9 No. 9 of Calorimetry is used for. (A) Finding the concentration of an unknown solution. (B) Finding the density of a sample. (C) Separating a sample. (D) Determining energy transfers. (E) Creating heat energy. Titrations determine the concentration of an unknown solution. B. Incorrect! Calorimetry studies energy transfers. C. Inorrect! Calorimetry studies energy transfers. D. Correct! Calorimetry studies energy transfers. Calorimetry studies energy transfers. Calorimetry studies energy transfers. The correct answer is (D).

10 No. 10 of 10 Instruction: (1) Read the problem statement and answer choices carefully (2) Work the problems on paper as 10. It is never alright to put what on a balance? (A) Glassware. (B) Containers with a liquid chemical. (C) Containers with a solid chemical. (D) Hot containers. (E) Empty containers. It is OK to use glassware on a balance. B. Incorrect! It is OK to place liquids in a container on a balance. It is OK to place solid chemicals on a balance if they are inside a container. D. Correct! One should not place hot containers on the balance, which could damage the balance and give inaccurate reading. This is OK to place empty containers on a balance, as long as it is not hot or wet. It is not OK to place hot containers on the balance. The correct answer is (D).