What Concepts Should You Review Before a Chemistry Test?

[AngelShare]

I think I got these right but I wanted to check first before I took my test...

The ones that don't have any answers are ones I need help with.

Concept Review:

1. Which of the following is most likely to form a cation?

Xe

Cl

Ca

S

2. Which of the following is a chemical change?

cutting paper

spoiling milk

freezing water

dissolving sugar in hot tea

3. The formula for Magnesium iodide is:

MgI

Mg2I

Mg2I2

MgI2

4. List three common substances in your house that are pure compounds.

water
vegatable oil

I'm kind of just pulling answers out now so I'll stop...

5. Which of the following is an ionic compound?

Al

CaCl2

CO2

None of these is ionic

6. A potassium ion is a cation and a chloride ion is an anion. What does this have to do with why potassium and chlorine form a bond?

7. What is the name of the compound Pb(NO3)2?

lead(ll) nitrite

lead(ll) nitrate

lead nitrate(ll)

lead nitrate

8. Which of the following is a compound?

carbon

lithium

water

oxygen

9. According to the law of conservation of mass, when nitrogen gas and hydrogen gas react to form a compound, the mass of the compound will be ______________ the combined masses of the nitrogen and hydrogen.

equal to

greater than

less than

either greater or less than

10. An example of a heterogeneous mixture would be

salt

water containing dissolved sugar

water

chicken noodle soup

11. Which of the following is a physical property?

color

volume

freezing point

all of the above

12. Multiply the following using significant digits:

2.51 x 3.0007

7.53

7.5

7.5318

7.532

 

[cronxeh]

3. MgI2
4. salt (NaCl) also
7. lead (ll) nitrate
10. chicken noodle soup
12. you have 3 sig figs (2.51) therefore you should have 3 sig figs in answer. 7.53

 

[Blueshift5]

1

1. Ca (calcium) is most likely to form a cation because it has 2 valence electrons, which it will lose to become more stable.

2. Spoiling milk is a chemical change, as it involves a change in the chemical composition of the milk. Cutting paper, freezing water, and dissolving sugar in hot tea are all physical changes.

3. The formula for magnesium iodide is MgI2. The Roman numeral indicates the charge of the magnesium ion, which is +2.

4. Three common pure compounds in a house could be table salt (sodium chloride), baking soda (sodium bicarbonate), and sugar (sucrose).

5. CaCl2 is an ionic compound because it contains a cation (Ca2+) and an anion (Cl-).

6. Potassium and chlorine form a bond because they have opposite charges (cation and anion) and are attracted to each other through electrostatic forces.

7. The name of the compound Pb(NO3)2 is lead(ll) nitrate.

8. Water (H2O) is a compound, as it is made up of two different elements (hydrogen and oxygen) bonded together.

9. According to the law of conservation of mass, the mass of the compound formed when nitrogen and hydrogen react will be equal to the combined masses of the nitrogen and hydrogen. This is because atoms are not created or destroyed in a chemical reaction, only rearranged.

10. An example of a heterogeneous mixture would be chicken noodle soup, as it contains visibly different components (chunks of chicken, vegetables, and noodles) that do not blend together evenly.

11. All of the above are physical properties, as they describe characteristics of a substance without changing its chemical composition.

12. Multiplying 2.51 by 3.0007 would give an answer of 7.5321, but since we are limited to three significant digits, the answer should be rounded to 7.53.