Chemistry Test Trimester (2nd Test)

Question 1

Characteristics of Acids

Answer 1

PH less than 7.
Sharp and sour taste.
Corrosive
Reacts with some metals and metal carbonates to form gas.
Turn blue litmus paper red.
Excess hydrogen ions.

Question 2

Characteristics of bases/alkali

Answer 2

PH more than 7.
Bitter taste.
Soapy feeling (slippery)
Do not react with metals.
Turn red litmus paper blue.
Excess hydroxide ions.

Question 3

Meaning of Acid

Answer 3

An acid is a substance that produces hydrogen ions, H+ are produced when it dissolves in water and can react with a base to make salt.

Question 4

Meaning of Base

Answer 4

A base is a solution of hydroxide ions, OH- are produced when bases dissolve in water and can react with an acid to make salt.

Question 5

How to interpret the PH scale.

Answer 5

0 - 6 = Acidic
Strong acid = 0 - 3
Weak acid = 4 - 6
7 = Neutral
8 - 14 = Basic
Strong base = 12 - 14 
Weak base = 8 - 12

Question 6

What can we use the PH scale for?

Answer 6

Garden - A sting from an ant or a bee is very
painful as it contains an acid — formic acid. This can be neutralized by a base such as soap. A wasp sting is painful because it contains a base and can be treated
by applying an acid such as vinegar.

Question 7

Meaning of Neutralization

Answer 7

A substance that has an equal number of Hydrogen (H+) and Hydroxide (OH-) ions.
PH equal to 7.

Question 8

Different Indicators

Answer 8

Litmus Paper - 
Acid = turn blue to red.
Base = turn red to blue.
Universal indicator - 
Using cabbage juice to see how it changes and depending on the color the liquid changes into is the PH.

Question 9

Acid Reaction with Metals

Answer 9

Acid + Metal = Salt + Hydrogen
Examples -
Magnesium + Hydrochloric acid → Magnesium Chloride + Hydrogen

Sulfuric acid + Iron → Iron(II) Sulfate + Hydrogen

Question 10

Acid Reaction with Metal Carbonates

Answer 10

Acid + Carbonate → Salt + Carbon Dioxide + Water
Examples -
Calcium carbonate + Hydrochloric acid → Calcium chloride + Carbon dioxide + Water

Sulfuric acid + Iron(II) carbonate → Iron(II) sulfate + Water + Carbon dioxide.

Question 11

Acid Reaction with Bases

Answer 11

Acid + Base → Salt + Water
Examples -
Copper(II) oxide + Hydrochloric acid → Copper(II) chloride + Water

Hydrochloric acid + Sodium hydroxide → Sodium Chloride + Water

Question 12

Salt names

Answer 12

Hydrochloride acid → (Metal name) Chloride
Sulfuric acid → (Iron) Sulfate
Nitric acid → (Sodium) Nitrate
Carbonic acid → (Calcium) Carbonate

Question 13

Reactants

Answer 13

The chemical(s)/element(s) you start with before the reaction occurs.
Think “Raw Material”
Written on the left side of the equation.
Where the “Arrow” begins.

Question 14

Products

Answer 14

The new chemical(s)/element(s) you get once the reaction occurs. 
Written on the right side of the equation.
Where the "Arrow" points.

Question 15

Coefficient

Answer 15

Shows how many molecules there are of a particular chemical.
Example: 3H (subscript 2) 0
Means there are 3 water molecules.

Question 16

Subscript

Answer 16

Shows how many atoms of an element are in a molecule.
Example: H (subscript 2) O
There are 2 atoms of hydrogen & 1 atom of oxygen.

Question 17

Counting Atoms

Answer 17

Add up the subscripts.
If there is a coefficient, multiply every subscript by that number.
If there is no subscript next to the element, then it is 1.

Question 18

Balancing Chemical Equation Problems

Answer 18

H (subscript 2) + Cl (subscript 2) → HCl
You would change it to:
H (subscript 2) + Cl (subscript 2) → 2HCl
because if you times 2 by them both it will be equal.

Question 19

Difference between Alkali and Base

Answer 19

All alkali is a base, but all bases are not alkali. Alkali is a base that dissolves in water.