Chemistry

Answers to Chapter 2 Study Questions

 

1.a)An element is a fundamental substance that cannot be broken down into simpler substances by chemical means.It is composed of atoms.

††††† b)A compound is a pure substance made of at least two elements in a fixed ratio.

††††† c)A pure substance can be an element or a compound.It has a constant composition.

 

2.a)air = mixture, solution††††††††††††††††† b)titanium = pure, element

††††† c)oak = mixture††††††††††††††††††††††††††† d)baking soda = pure, compound

††††† e)oxygen =pure, element f)7-Up = mixture, solution

††††† g)wine = mixture, solution h)carbon monoxide = pure, compound

 

3.a)element†††††††††††††† b)compound†††††††††††††† c)element††††††††††††††††††† d)mixture

††††† a)and b)contain molecules.

 

4.solid:particles not moving and close; liquid:particles moving and close; gas:particles moving and far apart; aqueous (dissolved in water):particles moving and far.

†††††

5.chemical:Chlorine reacts with sodium to form NaCl.You could also list the formula of any ionic compound chlorine forms, such as MgCl2, CaCl2, etc.

††††† physical:Chlorine is a pale green gas at room temperature.Itís a nonmetal made up of diatomic molecules.

 

6. Chemical reactions are frequently accompanied by:

††††† a)mass changes and/or bubbles which show that a gas is involved in the reaction.

††††† b)heat changes;heat is evolved in exothermic reactions;heat is used up in endothermic reactions.Exothermic reactions also often result in the production of light and sound.

††††† c)color changes which often signify a change in chemical composition.

††††† d)the formation of a precipitate (formation of a solid from mixing solutions) which represents the formation of an insoluble substance from soluble substances.

 

7.a)chemical b)physical†††††††††††††††††† c)physical†††††††††††††††††† d)chemical

††††† e)chemical††††††††††† f)chemical†††††††††††††††††† g)physical

 

8.a)Qualitative:This page is colorful.This page contains questions.

††††† b)Quantitative:This page is 8.5 in x 11 in.The page contains 9 questions.

††††† Theory:The questions on this page will be useful in studying for the test.

 

9.†† a)beaker†††††††††††††† b)Erlenmeyer flask††††††††††††††††† c)graduated cylinder†††††††††††††† d)pipet