Energetics

Question 1

What kind of reaction make the temperature increase ?

Answer 1

Exothermic

Question 2

Which reaction means the products have less energy than the reactants?

Answer 2

Exothermic

Question 3

What kind of reaction makes the temperature decrease?

Answer 3

Endothermic

Question 4

Which reaction means the products have more energy than the reactants?

Answer 4

Endothermic

Question 5

RP - Investigate temperature changes accompanying salts dissolving in water

Answer 5

1) set up apparatus
2) use a pipette, transfer 25cm3 of sodium hydroxide solution into cup, record temp after adding a few drops of phenolphthalein, record colour
3) use burette, add 2cm3 of dilute HCl to solution, stir mixture - record colour/ temp
4) continue to add 2cm3 of HCl, record

Question 6

RP - Investigate temp changes accompanying displacement reactions

Answer 6

1) add 50 cm3 of copper sulphate solution to cup (in beaker)
2) take initial temp
3) Calc mass of 0.05 of zinc metal, measure into weighing boat
4) add metal to solution, stir vigorously
5) record max temp
6) repeat experiment with two other metals

Question 7

Name the equation to calculate q

Answer 7

q=mc^T

Question 8

RP - investigate temp changes combustion

Answer 8

1) place 100cm3 of water in copper can, clamp it above a spirit burner
2) record starting temp of water
3) weigh spirit burner and lid
4) light burner, leave for 2 mins
5) after two mins, reweigh and record final water temp
6) repeat experiment with other alcohols

Question 9

Name 3 exothermic reactions

Answer 9

Combustion
Neutralisation
Burning

Question 10

Name 1 endothermic reaction

Answer 10

Thermal decomposition

Question 11

Neutralisation reaction

Answer 11

1) sodium hydroxide is poured into a beaker of HCl

2) beaker now contains sodium chloride and water

Question 12

Enthalpy of combustion

Answer 12

q=mc^T

Mass of water