This document provides practice problems for a general chemistry unit covering concepts such as physical and chemical changes, pure substances and mixtures, separation techniques, properties, and density. It includes questions asking students to define terms, analyze samples, identify properties, describe separation methods, design experiments, and perform calculations.

1. CHM 111 General Concepts Unit 1 Practice Problems
1. Which of the following are physical and which are chemical changes? Briefly explain your answers.
Change Physical Chemical
Dew forming on the grass
Cooking eggs
Brewing coffee (Hint: Could you
separate the water from the molecules
extracted from the coffee?)
Separating isopropyl alcohol and water
Photosynthesis by plants
2. a) Define the terms below.
Pure substance-
Element-
Compound-
Mixture-
b) Analyze the samples given below. The two different types of atoms are identified by the following
symbols: o and . Identify the substances in the boxes according to the following criteria:
P = pure substance E = element C = compound M = mix
Element or Compound? ______ _____________ ______
Pure substance or Mixture? ______ _____________ ______
10 nm10 nm 20 nm

2. CHM 111 General Concepts Unit 1 Practice Problems
3. a) Identify the substances in the boxes as heterogeneous or homogenous.
b) Provide an example of a homogeneous mixture from your everyday experience.
c) Provide an example of a heterogeneous mixture from your everyday experience.
4. a) Define the two terms listed below and provide an example from your everyday experience:
Intensive property-
Extensive property-
b) Identify the following as intensive (I) or extensive (E) properties:
________ temperature ________ boiling point
________ volume ________ color
________ odor ________ mass
________ density ________ electrical conductivity
5. Three ways to separate mixtures are described in the textbook; filtration, distillation, and
chromatography. Briefly describe each of these techniques.
Filtration-
10 nm10 nm 20 nm

3. CHM 111 General Concepts Unit 1 Practice Problems
Distillation-
Chromatography-
6. You have a mixture of sand and salt. Design a simple separation, explaining your procedure step by
step and include a labeled drawing for each step. You may use whatever materials you need to do
the separation. Is the separation a physical or chemical process?
Step 1. Obtain the salt and sand mixture.
Step 2.
Step 3:
Step 4:
Step ____.
7. A solution of methyl t-butyl ether has a volume of 65.0 mL and a mass of 48.23 grams. Determine
the density for this solution.
8. Suppose a student has three balls of equal mass. Determine which of the balls is the largest. Show
any appropriate equations and/or calculations and justify your answer with a brief sentence.
Densities: a = 3.24 g/mL b = 1.56 g/mL c = 0.650 g/mL