Further analysis and quantitative chemistry

Question 1

What are moles

Answer 1

It’s a very big number

When you get that number of atoms it weighs the same number of grams as the atomic mass

Question 2

What can concentration be measured in

Answer 2

Moles per dm^3

1 dm^3 = 1 litre = 1000cm^3

Question 3

What is 56 grams of “stuff” dissolved in 1 dm^3 of solution?

Answer 3

56 grams per dm^3

Question 4

What happens to the concentration when you dissolve more solute?

Answer 4

The more solute you dissolve in a given volume the more crowded the solute molecules and the more concentrated the solution. What

Question 5

What can titrations be used for?

Answer 5

Titrations allow you to find out exactly how much acid is needed to neutralise a quantity of alkali (or vice versa)

Question 6

Explain how you would do a titration?

Answer 6

Put some alkali into a flask along with some indicator,
Add the acid a drop at a time using the burette,
Swirl the flask,
When the indicator changes colour, all the alkali has been neutralised,
Record the amount of acid used to neutralise the alkali and repeat the process

Question 7

What is the formula for finding the concentration in moles per dm^3

Answer 7

n = c * V

n = number of moles,
c = concentration in mol/dm^3
V = volume in dm^3 

(Triangle has n at top)

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Question 8

What is the formula for concentration in grams per dm^3

Answer 8

m = n * M_r

m= mass in grams 
n= number of moles
M_r = relative formula mass

(Triangle with m at top)

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Question 9

How can you reduce heat lost when measuring energy transfer

Answer 9

Adding a lid

Putting the cup into a beaker of cotton wool

Question 10

What is an exothermic reaction?

Answer 10

An exothermic reaction is one which gives out energy to the surroundings usually in the form of heat and usually shown by a rise in temperature.
Fuels burning
Neutralisation

Question 11

What is an endothermic reaction?

Answer 11

An endothermic reaction is one which takes in energy from the surroundings, shown by a fall in temperature
Photosynthesis

Question 12

What happens to bonds during a chemical reaction?

Answer 12

Old bonds are broken and new bonds are formed

Question 13

Explain the energy given out and taken in, in relation to bonds

Answer 13

Energy must be supplied to break bonds and energy is released when bonds form

Question 14

What type of process is bond breaking?

Answer 14

Energy must be supplied to break bonds, so bond breaking is an endothermic reaction

Question 15

What process is bond formation?

Answer 15

Energy is released when new bonds are formed, so bond formation is an exothermic process

Question 16

In an endothermic reaction is the energy required greater than the energy released?

Answer 16

In an endothermic reaction, the energy required to break old bonds is greater than the energy released when new bonds are formed

Question 17

Describe the energy released in an exothermic reaction

Answer 17

In an exothermic reaction, the energy released in bond formation is greater than the energy used in breaking old bonds

Question 18

What is calorimetry?

Answer 18

Fuel energy is calculated using calorimetry

Question 19

How do you measure the amount of energy released when a girl is burnt?

Answer 19

You burn the fuels and use the flame to heat up some water.

Question 20

What is the equation for calorimetry?

Answer 20

Q = mc 🔼 T

Q = energy transferred in joules 
m = mass of water in grams 
c = specific heat capacity 
🔼T = temperature change in degrees Celsius

Question 21

What does an exothermic energy level diagram look like?

Answer 21

It looks like a step down

Question 22

What does an endothermic energy level diagram look like?

Answer 22

It’s a step up

Question 23

What is the activation energy

Answer 23

The minimum energy needed by reacting particles to break their bonds

Question 24

What does a catalyst do to the activation energy!,

Answer 24

A catalyst lowers the activation energy