Exam 1: Introduction to Chemistry

Focus on Problem Solving Exercises A solution of ethanol in water has a volume of 54.2 mL and a mass of 49.6 g. What information would you need to look up and how would you determine the percentage of ethanol in this solution?

Insight into Aluminum Use the web to determine the amount of aluminum used in the US in a single year. What is the primary use for this material?

Problem Solving in Chemistry and Engineering Draw a molecular scale picture to show how a crystal differs from a liquid.

Problem Solving in Chemistry and Engineering If a particle is traveling at 98% of the speed of light in a vacuum (2.998 x 10⁸ m/s), what is its velocity in miles per hour? 1.00 miles = 1.61 km.

The Study of Chemistry Do the terms element and atom mean the same thing? If not how do they differ?

Observations and Models Suppose you are waiting at a corner for a bus. Three different routes pass this particular corner. You see a bus pass by from the two routes you are not interested in taking. When you say to yourself, "My bus must be next," what type of reasoning (deductive or inductive) are you using? Explain your answer.

Problem Solving in Chemistry and Engineering The distance between two atoms in a molecule is 148 pm. What is this distance in meters?

Insight into Aluminum Use the web to determine the difference in how much aluminum is recycled in states where there are deposits on aluminum cans versus states where recycling is voluntary? What is the most reliable way to estimate this value? What uncertainty is there in the estimate?

Insight into Materials Selection and Bicycle Frames Aluminum is not as strong as steel. What other factor should be considered when comparing the desirability of aluminum versus steel if strength is an important consideration for a design?

The Study of Chemistry How can a liquid be distinguished from a fine powder? What type of experiment or observation might be undertaken?

Numbers and Measurements Oxygen boils at − 186 ° C. What is this temperature in Kelvin?

Observations and Models What is the difference between a hypothesis and a question?

Numbers and Measurements What is a "derived" unit?

Focus on Problem Solving Exercises Imagine you place a cork measuring 1.30 cm × 4.50 cm × 3.00 cm in a pan of water. On top of this cork you place a small cube of lead measuring 1.15 cm on a side. Describe how you would determine if the combination of the cork and lead cube will still float in the water. Note any information you would need to look up to answer the question.

The Study of Chemistry Why do physical properties play a role in chemistry if they do not involve any chemical changes?

Numbers and Measurements Express each of the following temperatures in ° C. a) 177 K b) 298 K c) 4 K d) 1500 K

The Study of Chemistry Which of the following items are matter and which are not? a) a flashlight b) sunlight c) an echo d) air at sea level e) air at the top of Mount Everest

Insight into Aluminum What properties of aluminum might cause you concern if you had to use the aluminum tableware that Napoleon employed to impress his guests?

The Study of Chemistry All molecules attract each other to some extent, and the attraction decreases as the distance between particles increases. Based on this idea, which state of matter would you expect has the strongest interactions between particles, solids, liquids or gases?

Numbers and Measurements How many significant figures are present in each of the following experimental measurements? a) 0.003 m b) 6030 kg c) 400.3 s d) 0.000701 L e) 31.624 km