Chemisty Test

Question 1

What is the pH scale and what does it measure?

Answer 1

pH scale is used to determine how acidic or basic a substance is. Measures the number of H+ ions in the solution and where the solution falls between 1-14. 1 is the most acidic, 14 is the most basic, 7 is neutral.

Question 2

Two things that affect the strength of an acid/base?

Answer 2

Concentration and Percent Ionization affect the strength. Percent. affects the strength because the more molecules that ionize, in an acid/base, the stronger it is. Concentration affects the strength because the more acid/base per liter of water the stronger it is.

Question 3

Percent ionization

Answer 3

It is the number of H+ molecules that will ionize (break apart) for every 100 molecules dissolved in water.

Question 4

Concentration

Answer 4

It is the amount of pure acid or base dissolved per liter of water.

Question 5

Main indicators and what colours they turn into.

Answer 5

Red litmus paper - acid (stays red) base (turns blue)

Blue litmus paper - acid (turns red) base (stays blue)

Phenolphthalein - acid (turns cloudy white) base (turns ruby red)

Question 6

Acid (define, properties, disassociate)

Answer 6

Are compounds that contain hydrogen and that form a H+ ion when dissolved in water.
Properties: taste sour, react with metals, good conductors, pH between 1-7.

Question 7

Base (define and properties)

Answer 7

Are compounds that contain OH- molecules and that form OH- ions when dissolved in water.
Properties: taste bitter, good conductors, react with proteins to break into smaller pieces, pH 7-14.

Question 8

Cause and effect of acid rain on environment.

Answer 8

Acid rain is caused by gas emissions from smelters, industrial facilities, electrical utilities, and transportation (cars, buses). Acid rain often affects lakes and streams. As the pH lowers, making the water more acidic, insects and plankton start to vanish, which are food sources for fish. Fish start to die or have trouble reproducing, which means land animals have a decreased food source. Provinces in the Cansdian shield, such as ontario, the soils and waterways have a hard time naturally reducing the effects acid precipitation. There is lots of granite rock, which is not a natural base.

Question 9

What have we done to reduce the affects of acid rain?

Answer 9

We have added a base to neutralize an acid when there is an acid spill. Liming lakes also help to neutralize an acidic lake. Liming is a bunch of crushed up base (limestone is one) and it is dumped into the lake.

Question 10

4 types of chemical reactions

Answer 10

Synthesis- A + B = AB
Decomposition- AB= A + B
Single Displacement- AB + C = AC + B (reaction only happens if C is more reactive)
Double Displacement- AB + CD = AD + CB

Question 11

Law of Conservation

Answer 11

The mass of reactants is equal to the mass of the products. (Balancing equations, both sides must be equal) (Reactants on first half, products on the other)

Question 12

Classical system

Answer 12

Are Latin names ending in “ic” if the charge is higher and “ous” if the charge is lower on a transition metal.

Question 13

Stock system

Answer 13

Roman numerals are the charge

Question 14

Why does no reaction take place in single. sometimes?

Answer 14

Because the alone metal’s reactivity is not higher than the metal in the compound.

Question 15

Ionic compound (define and properties)

Answer 15

Is a metal and a non-metal combined.
Properties: crystal structure, rough texture, high melting point, dissolves easily in water, good conductors.

Question 16

Covalent compound (define and properties)

Answer 16

Is two non-metals combined.
Properties: smooth structure/feel, low melting point, bad conductors, don’t dissolve in water.

Question 17

Atom (particles and where they’re located)

Answer 17

Electrons- found in outer shells, have almost no mass, negative charge.
Protons- found in the nucleus, have a mass of 1u, positive charge.
Neutrons- found in the nucleus, no charge, have a mass of 1u.