Review

Chemical and Physical ChangesChemical and physical properties

Conservation of massReaction Rates

For each of the following, give an example of what you might see in a chemical reaction that would

indicate…..:a. color changeb. energy changec. Precipitated. gas formation

For each of the following, give an example of what you might see in a chemical reaction that would

indicate…..:a. color change color disappears or you get a

color that isn’t the result of color wheel mixing (ex..yellow + blue = green, this doesn’t necessarily indicate a color change)

b. energy change temperature change, got hotter or colder, light produced

c. Precipitate formation of a solidd. gas formation bubbles/foaming

• Which of the following would increase the rate of a reaction?

a)Increase temperatureb)Decrease concentrationc) Adding a catalystd)Decreasing temperaturee)Decreasing the surface area

• Which of the following would increase the rate of a reaction?

a)Increase temperatureb)Decrease concentrationc) Adding a catalystd)Decreasing temperaturee)Decreasing the surface area

Which of these equations are balanced?

1. H2CO3 → H2O+ CO2

2. NH3 + H2O → 3NH4OH

3. SnO2 + H2 → Sn + H2O

Which of these equations are balanced?

1. H2CO3 → H2O+ CO2

2 H, 1 C, 3 O 2 H, 1 C, 3 O

2. NH3 + H2O → 3NH4OH

1 N, 5H, 1 O 3 N, 15 H, 3 O

3. SnO2 + H2 → Sn + H2O

1 Sn, 2 O, 2H 1 Sn, 1 O, 2H

What can you do to balance this equation.

2. NH3 + H2O → 3NH4OH

What can you do to balance this equation.

2. NH3 + H2O → 3NH4OH

NH3 + H2O → NH4OH

Which of these reactions is exothermic…how do you know?

Which is endothermic…how do you know?

1. H2CO3 → H2O+ CO2 + energy

2. NH3 + H2O + energy → 3NH4OH

3. SnO2 + H2 → Sn + H2O

Living things obtain energy through this reaction

O₂ + C₆H₁₂O₆ CO₂ + H₂O + energy

The process reflected by this equation is____

1. If the masses of the reactants are 19g and 24g, what will be the mass of the products?

2. In the following equation:SnO2 + 2 H2 → Sn + 2 H2O

The mass of SnO2 is 6g, the mass of Sn is 2g, and the mass of H2O is 8 grams, what is the mass of H2 ?

__________________ ______________ (what are substances on this side of the arrow called?) (what are substances on this side of the arrow called?)

Matching…1. products2. Chemical change/reaction3. Catalyst4. Reactant

A. A substance that increases the rate (speeds up) of a chemical reaction but is not consumed in the reaction

B. Every chemical reaction forms at the end of the reactionC. Changes the way in which atoms are arranged by causing

bonds between the atoms to break and new bonds to form between different atoms.

D. A substance present at the beginning of a chemical reaction

matching1. Specific Heat2. Precipitate3. Temperature4. Surface Area

A. Affects the rate of a chemical reaction by changing the speed at which particles of reactants move

B. Affects the rate of a chemical reaction by increasing the number of molecules of one reactant that are exposed to the other reactant.

C. A solid product that sometimes forms when chemicals in liquids react

D. The amount of energy required to raise the temperature of 1g of material 1 degree

1 Which is a more suitable material for roofers to use when removing iron nails from a yard: magnets or water?

2 Which is a more suitable material to “foil” teeth in dental work: Carbon

(C) Tin (Sn)?

4 Which is a more suitable material for power lines: Selenium (Se) or Tungsten (W)

5 Which is a more suitable material for use in water pipes: Potassium (K) or

Copper (Cu)?

6 Which is a more suitable material to stir boiling liquid for a long time: a Silicon (Si) spoon or an Aluminum (Al) spoon?

7 Which is a more suitable material for creating a reflective surface on the

back of a mirror: Silver (Ag) or Arsenic (As)?

1 Which is a more suitable material for roofers to use when removing iron nails from a yard: magnets or water? Becaue they are metals and a physical property of metal is magnetism.

2 Which is a more suitable material to “foil” teeth in dental work: Carbon (C) Tin (Sn)? Because metals are malleable and nonmetals are brittle. Tin is a metal, carbon is a nonmetal.

4 Which is a more suitable material for power lines: Selenium (Se) or Tungsten (W) Because metals are conductive, tungsten is a metal and selenium is a non metal

5 Which is a more suitable material for use in water pipes: Potassium (K) or Copper (Cu)? Because copper is a transition metal which is stable and Potassium is a member of the alkali metal group which is unstable and reacts with water.

6 Which is a more suitable material to stir boiling liquid for a long time: a Silicon (Si) spoon or an Aluminum (Al) spoon? Because silicon is a metalloid and therefore conducts heat poorly, aluminum is a metal and conducts heat….an aluminum spoon gets HOT

7 Which is a more suitable material for creating a reflective surface on the back of a mirror: Silver (Ag) or Arsenic (As)? Silver is a metal and therefore shiny, Arsenic is a nonmetal and therefore dull. A mirror needs to have a shiny backing so it will reflect light and your image

• Your brother finds a golden-colored cube at a flea market. The price is $100, and your brother is sure that it is gold. You pull out your old geology textbook and look up gold in the mineral table, and read that its density is 19.3 g/cm3. You test the cube and find that it displaces 8 cm3 of water, and has a mass of 40g. What is the cube’s density? Is it gold? Should you buy it?

The gold colored cube has a density of 40/8 = 5 g. It does not have the same density as gold, therefore it is not gold.