2- Chemical Reactions

Question 1

Methane gas (CH4) reacts with O2 to produce ..?

Answer 1

CO2 and H2O

Question 2

What is a subscript?

Answer 2

The subscript ​identifies the number of atoms of a certain element present in a specific molecule. (subscripts never change)

Question 3

What is a coefficient?

Answer 3

The coefficient​ identifies the number of molecules present in the specific chemical equation. (always written in front of formula)

Question 4

What is a Redox reaction?

Answer 4

Redox reactions involve both oxidation and reduction​, which occur together in a chemical reaction​: one of the reactants is oxidised and one is reduced​

Question 5

Oxidation-Reduction (Redox) Reaction:

Answer 5

A redox reaction is a chemical reaction in which there is a transfer of electrons from one reactant to another​

Question 6

​A Non-oxidation-Reduction (Non-redox) Reaction​:

Answer 6

A non-redox reaction is a chemical reaction in which there is no transfer of electrons from one reactant to another​.

Question 7

What happens to electrons in a redox reaction?

Answer 7

if there is a loss of electrons (oxidation), these electrons must be accepted somewhere else (reduction)

Question 8

OIL=

RIG​=

Answer 8

Oxidation Is Loss (of electrons or hydrogens)

Reduction Is Gain (of electrons or hydrogen)​

Question 9

Energy is found in the bonds between atoms​

Answer 9

Oxidation is a decrease in the energy content of a molecule​

Reduction is the increase in the energy content of a molecule ​

Question 10

Why does oxidation involve the gaining of oxygen?

Answer 10

Oxidation is gain of oxygen. Reduction is loss of oxygen

Question 11

Oxidation may involve​:

Reduction may involve​:

Answer 11

Oxidation:
The loss of H or ​
The gain of O​

Reduction​:
The gain of H or ​
The loss of O​

Question 12

3 common coenzymes of living cells that carry H atoms​?

Answer 12

NAD+ (nicotinamide adenine dinucleotide)​
NADP (nicotinamide adenine dinucleotide phosphate) ​
FAD (flavin adenine dinucleotide)​

Question 13

Biological reduction is…..?

Answer 13

the addition of electrons and hydrogen atoms​. Molecules that undergo reduction become more energy-rich​.

Question 14

What are reversible reactions?

Answer 14

Reversible reactions are chemical reactions that can be reversed

eg H2O(g) + CO(g) ↔ H2(g) + CO2(g)​

Question 15

What is chemical equilibrium?

Answer 15

Chemical equilibrium is the state in which forward and reverse chemical reactions​ occur simultaneously at the same rate

Equilibrium is not stationary
When chemical equilibrium is achieved, the concentrations of reactants and products no longer change, however, they also do not have to be equal.

Question 16

What is Le Châtelier’s Principle?

Answer 16

If a stress is applied to a system in equilibrium, the system will ​readjust in the direction that best reduces the stress on the system

Question 17

writing reduction and oxidation..

Answer 17

reduction = + written on the left
oxidation = + written on the right

Question 18

What are the reactants and products?

Answer 18

reactants = starting materials (on left)
products = resulting substances (on right)

Question 19

3 steps for balancing chemical equations:

Answer 19

1) Write the unbalanced equation
2) Balance the equation.
3) Indicate the states of matter of the reactants and products.