Measurement of enthalpy change

Question 1

Describe an experiment to find enthalpy change adding one reagent to another

Answer 1

Measure 25cm3 of a solution with a known concentration into a polystyrene cup.
Put the polystyrene cup into a beaker to prevent it tipping over
Measure the initial temperature using a thermometer put it into a table
Start a timer and measure the temperature in intervals of 1 minute. At the 4th minute do not measure the temperature instead add 25cm3 of a known solution or a measured mass and add it to the cup.
Use a stirring rod and stir for the rest of the time before measuring the temperature at the 5th minute then re beginning the temperature measuring process until the 10th minute.
Plot a temperature against time graph with your results.

Question 2

Describe an experiment to find the combustion of fuel in a spirit burner

Answer 2

Weigh mass of the spirit burner
Measure 100cm3 of water into a beaker and place it above the spirit burner
measure the temperate of the water and record it in a table
light the wick of the spirit burner
allow the temperature of the water to rise approx 20-25°C
extinguish the spirit burner and record its mass in the table.

Question 3

What can be done to improve the experiment of enthalpy change when adding one reagent to another

Answer 3

Use a lid to reduce heat loss
Account for the initial temperature for reagent added to former reagent

Question 4

Why are the experimental values of adding a reagent to another never accurate

Answer 4

Heat loss
Incomplete reaction

Question 6

How to find mass of fuel burned away

Answer 6

Mass of fuel burner and mass of gas at the start - mass of fuel burner mass of gas’s at the end of the

Question 7

How to find mathematical find enthalpy change

Question 8

How to mathematically find enthalpy change

Answer 8

q=mc