Chemistry Homework #1

electrical conductivity

Pg 130 #1-12

1.     Classify each of the following as a chemical or a physical property:

a.     COPPER HAS A REDDISH BROWN COLOR: physical property

b.     PROPANE BURNS READILY: chemical property

c.      CO₂ GAS EXTINGUISHES A CANDLE FLAME: chemical property

d.     HONEY POURS MORE SLOWLY THAN DOES WATER: physical property

2.     Classify each of the following as a chemical or a physical property:

a.     METAL WIRE CAN BE BENT: physical property

b.     ICE FLOATS IN WATER: physical property

c.      PAPER IS FLAMMABLE: chemical property

d.     SUGAR IS SOLUBLE IN WATER: chemical property

3.     Classify each of the following as a chemical or a physical change:

a.     A CANDLE BURNS: chemical change

b.     AN OPEN CARBONATED BEVERAGE FIZZES: chemical change

c.      HAIR CURLS AS A RESULT OF A “PERM”: physical change

d.     AS SHOES WEAR OUT, HOLES APPEAR IN THEIR SOLES: physical change

4.     Classify each of the following as a chemical or physical change:

a.     A CUT APPLE LEFT OUT IN THE AIR TURNS BROWN: chemical change

b.     FLASHLIGHT BATTERIES LOSE THEIR “CHARGE” AFTER EXTENDED USE: physical change

c.      DRY CLEANING REMOVES OILS FROM CLOTHING: chemical change

d.     ITALIAN SALAD DRESSING SEPERATES OVER TIME: physical change

5.     For each of your answers in Question 4, give evidence for your classification as a chemical or physical change.

a.     A CUT APPLE: The oxygen in the air reacts with the molecules in the apple, which causes it to turn brown.

b.     FLASHLIGHT BATTERIES: for each use of the battery, the power in the battery decreased which was not a chemical change because nothing had to react with it to have it lose power.

c.      DRY CLEANING: to clean oils the cleaners have to use a nonpolar substance that can easily dissolve it which involves using another chemical.

d.     ITALIAN SALAD DRESSING: This is a physical change because in order for it to separate does not require any sort of reaction by another chemical.

6.     A. List the steps involved in making chocolate chip cookies from scratch.

a.     Gathering the materials needed and mixing together

b.     Putting in oven and baking

B. Classify each step in question 6a as involving either a chemical change or a physical change.

            a. Physical change

            b.  Chemical change           

7.     Classify each property as characteristic of metals or nonmetals:

a.     SHINY IN APPEARANCE: metal

b.     DOES NOT REACT WITH ACIDS: nonmetal

c.      SHATTERS EASILY: nonmetal

d.     ELECTRICALLY CONDUCTIVE: metal

8.     Classify each of these elements as a metal, a nonmetal or a metalloid:

a.     TUNGSTEN: metal

b.     ANTIMONY: metalloid

c.      KYRPTON: nonmetal

d.     SODIUM: metal

9.     List the names and symbols of two elements that are metalloids.

a.     Boron (B)

b.     Silicon (Si)

10. What would you expect to happen if you tapped a sample of each of the following elements with a hammer?

a.     IODINE: brittle

b.     ZIRCONIUM: malleable

c.      PHOSPHORUS: brittle

d.     NICKEL: malleable

11. List two properties that make nonmetals unsuitable for electric wiring.

a.     It is brittle and is an insulator

12. List three properties that make metals suitable for use in coins.

a.     Malleable

b.     Ductility

c.      luster