REQUIRED PRACTICAL rate of reaction

Question 1

define a hypothesis

Answer 1

a proposal that could explain a fact or an observation

Question 2

METHOD FOR THE
disappearing cross-practical
(required practical to measure how the concentration of a reactant affects the rate of reaction

Answer 2

• use a measuring cylinder to put 10 cm cubed of sodium thiosulfate solution into a conical flask
• place the conical flask onto a printed black cross
• add 10 cm cubed of hydrochloric acid into the conical flask
• swirl the solution and start a stopwatch
• look down through the top of the flask
• stop the stopwatch when the solution goes cloudy
• do the experiment again using lower concentrations of sodium thiosulfate solution
• repeat the whole experiment and calculate the mean values for each concentration of sodium thiosulfate solution

Question 3

what forms as a product when

sodium thiosulfate reacts with hydrochloric acid

( sodium thiosulfate + hydrochloric acid —> )

Answer 3

sodium thiosulfate + hydrochloric acid —> sulfur (solid makes solution go cloudy)

Question 4

define reproducibility

Answer 4

a measurement is reproducible if it can be repeated by another person (using a different technique/equipment) and still get the same result

Question 5

what forms as products in this reaction:

magnesium + hydrochloric acid —->

Answer 5

magnesium + hydrochloric acid —-> magnesium chloride + hydrogen

Question 6

method to producing a gas to show the effect of concentration on the rate of reaction

Answer 6

• use a measuring cylinder to measure 50 cm cubed of hydrochloric acid into a conical flask
• attach the conical flask to s bung and delivery tube
• place the delivery tube into a container filled with water
• place an upturned measuring cylinder filled with water over the delivery tube
• add a 3 cm strip of magnesium to the hydrochloric acid and start a stopwatch
• reaction produces hydrogen gas which is trapped in the measuring cylinder
• every 10 seconds measure the volume of hydrogen gas in the measuring cylinder and continue until no more hydrogen is given off
• repeat the experiment using different concentrations of hydrochloric acid

Question 7

if you increase the concentration what happens to the rate of reaction

Answer 7

increase the concentration = greater rate of reaction