measuring rate of reactions

Question 1

equation for rate of reaction

Answer 1

rate of reaction = amount of reactant used or amount of product formed DIVIDED by time

Question 2

precipitation and colour change

Answer 2

• you can record VISUAL CHANGE in a reaction if the initial solution is TRANSPARENT and the product is a PRECIPITATE which CLOUDS the solution (becomes opaque).
• you can observe a MARK through the solution and measure how long it takes for it to DISAPPEAR- the faster it disappears the quicker the reaction.
• if reactants are COLOURED and for the products are COLOURLESS, you can time how long it takes for the solution to LOSE OR GAIN IT’S COLOUR.
• results are very SUBJECTIVE.

Question 3

change in mass (gas usually given off)

Answer 3

• measuring the speed of a reaction that PRODUCES A GAS can be carried out using a MASS BALANCE.
• as the gas is released, the mass DISAPPEARING is measured on the balance.
• the QUICKER the reading on the balance DROPS, the FASTER the reaction.
• take measurements at REGULAR INTERVALS, you can plot a rate of reaction GRAPH and find the rate quite easily.
• most accurate out of all 3 methods because the mass balance is very accurate. bit also has disadvantage of releasing gas straight in a room.