Calculations

Question 0

1dm(cb) =

1cm(cb) =

Answer 0

1000cm(cb)

0.001dm(cb)

Question 1

Titration calculation equation

Answer 1

Moles = volume of solution (dm[cb]) x concentration of solution (mol dm [-cb])

Question 2

How to tackle a molar concentration question

Answer 2

Draw a table of volume concentration moles and ratio and fill them in using the calculation

Question 3

What are titrations used for

Answer 3

They are used to determine the concentration of a known substance usually an acid or alkali

Question 4

How to determine the concentration of a known solution via titration

Answer 4

• titrate HCl against 10ml portions of sodium hydroxide solution
• fill the burette with the HCl and pippette 10ml of the sodium hydroxide into a flask
• add methyl orange indicator into the flask
• titrate the acid against the sodium hydroxide in the flask until the end point is reached
• calculate the average titre

Question 5

Calorimetry is the

Answer 5

Enthalpy change in a reaction

Question 7

Enthalpy equation

Answer 7

Enthalpy = mass of solution 1cm(cb)/1g x specific heat capacity 4.18 x change in temperature 
Q = mc(tri)T

Question 8

The ionic equation for the redox reaction (displacement reaction) between zinc and copper(II) sulphate is

Answer 8

Zn(s) + Cu [2+] (aq) –> Zn [2+] (aq) + Cu (s)

Question 9

How to determine the enthalpy change for a reaction

Answer 9

An excess of zinc powder is added to a known volume of aqueous copper (II) sulphate and the temperature change is measured over a period of time so that the enthalpy change can be determined

Question 10

how to extrapolate a graphs curve

Answer 10

draw a line roughly through the crosses on the graph after the required time the question has asked about. then draw a line perpendicular to it from the x axis to meet with the other line until a point is reached and an answer is determined