Energy from fuels

Question 1

What is meant by COMPLETE COMBUSTION?

Answer 1

When a fuel reacts with a PLENTIFUL supply of oxygen

Question 2

List the products of a reaction of hydrocarbons or alcohols with a plentiful supply of oxygen.

Answer 2

carbon dioxide

water

Question 3

What are the units for specific heat capacity?

Answer 3

KJ^-1 Kg^-1 ^0C (for chem)

Question 4

Write the full balanced chemical equation for the complete combustion of ethane

Answer 4

C_2H6 + 3 and 1/2 O2 —-> 2CO_2 + 3H_2O

Question 5

What products are made during incomplete combustion that are not made by complete combustion?

Answer 5

carbon OR carbon monoxide or both

Question 6

Write the full balanced chemical equation for the complete combustion of propanol

Answer 6

C_3H_7OH + 4 and 1/2 O_2 —-> 3CO_2 + 4H_2O

Question 7

The quantity of heat energy released from burning a fuel can be determined experimentally. Sketch the apparatus required to give the most accurate results.

Answer 7

Burning fuel under a container containing a known quantity of water. A thermometer to measure the initial and final temperature of water. More accurate results are given if the container for the water is metal (a conductor), a draught shield is used (to prevent heat energy escaping into the surroundings), a stirrer is used (to evenly distribute the heat energy in the water), oxygen is supplied (for complete combustion).

Question 8

Write an equation to calculate the change in temperature of a known mass of water heated by a burning fuel. The energy released is known as well as the specific heat capacity of water

Answer 8

————-E_H
dT= ____
c x m

Question 9

Write an equation to calculate the change in temperature of a known mass of water heated by a burning fuel. The energy released is known as well as the specific heat capacity of water

Answer 9

————-E_H
dT= ____
c x m

Question 10

State the equation used to determine the energy released from a burning fuel if the fuel is heated under a known volume of water. The specific heat capacity of water and the temperature change of the water is also known.

Answer 10

E_H = cmdT

Question 11

Write the full balanced chemical equation for the complete combustion of methane

Answer 11

CH4 + 3O2 —-> CO_2 + 4H_2O

Question 12

What is meant by INCOMPLETE COMBUSTION?

Answer 12

Combustion when oxygen is limited

Question 13

1cm^3 of water is how many ml?

Answer 13

1

Question 14

Write an equation to calculate the mass of water heated when the specific heat capacity is known. The energy released is known as well as the change in temperature.

Answer 14

—————E_H
m = ______
c x dT

Question 15

What gas turns limewater cloudy?

Answer 15

Carbon dioxide

Question 16

What is meant by EXOTHERMIC REACTION

Answer 16

A reaction that releases heat energy into the surroundings

Question 17

What gas is required for combustion to take place?

Answer 17

Oxygen

Question 18

What is meant by ENDOTHERMIC REACTION

Answer 18

A reaction that absorbs heat energy from the surroundings

Question 19

What is the chemical test for water?

Answer 19

Blue cobalt chloride paper turns pink

Question 20

What is COMBUSTION?

Answer 20

When a substance reacts with OXYGEN and releases ENERGY

Question 21

A student carried out an experiment to measure the energy released when a fuel burns. They measured the heat energy transferred to a known volume of water. Suggest a reason why the students results were lower than the theoretical values.

Answer 21

Heat loss to the surroundings, evaporation of the fuel from the spirit burner, distance between the copper can and the spirit burner, incomplete combustion of the fuel.

Question 22

What would be the best piece of apparatus to measure out 50ml of water?
Beaker
Measuring cylinder

Answer 22

Measuring cylinder