PAG 12 - Research skills

Question 1

What is a prediction using scientific

knowledge called?

Answer 1

Hypothesis

Question 2

What is meant by the term accuracy?

Answer 2

How close the measurement is to the

true value

Question 3

What are variables?

Answer 3

Factors that can affect the outcome of

the experiment

Question 4

What is an independent variable?

Answer 4

A factor that is changed during the
experiment to see the effect it has on
another factor.

Question 5

What is a dependent variable?

Answer 5

A factor that is measured or observed in

the experiment.

Question 6

What is a control variable?

Answer 6

A factor that is kept constant throughout

the experiment.

Question 7

What is oxidation?

Answer 7

The loss of electrons or increase in

oxidation state

Question 8

What is reduction?

Answer 8

The gain of electrons or decrease in

oxidation state

Question 9

What is a redox reaction?

Answer 9

A reaction in which some atoms are

oxidised and others are reduced

Question 10

How can the percentage of iron in iron

tablets be found?

Answer 10

1. Prepare a standard solution of iron (II) using the tablets and sulfuric acid
2. Titrate a set volume of this iron(II) solution against a solution of KMnO4
3. Repeat until you obtain concordant results and calculate a mean titre
4. Calculate the number of moles of KMnO4
   that reacted
5. Use the ratio in the chemical equation to calculate the number of moles of
   iron that reacted
6. Calculate the percentage mass of iron using the mass present in the
   standard solution

Question 11

Describe how to make a standard

solution of acidified iron(II) sulfate

Answer 11

1. Grind up some iron tablets. Measure the total mass of the iron tablets in a weighing
   boat.
2. Add the powdered tablets to a conical flask and reweigh the weighing boat. The
   difference between the masses is the mass of iron tablets in the solution.
3. Add a 50cm3
   of sulfuric acid to the conical flask to dissolve the iron. Stopper the
   flask and shake well. Leave the flask for the residue to settle.
4. Filter the solution into a volumetric flask without disturbing the residue. Rinse the
   filter paper with a small volume of distilled water.
5. Fill the volumetric flask up to the graduation mark with sulfuric acid then stopper
   and invert the flask to mix.

Question 12

Write an equation for the redox reaction
between iron(II) ions and manganate(VII)
ions

Answer 12

5Fe2+ + MnO4- + 8H+ → 5Fe3+ + Mn2+ + 4H2O

Question 13

When making a standard solution, what
method should be used to find the mass
of solute?

Answer 13

Weighing-by-difference method

Question 14

Why is an indicator not required in the

titration between Fe2+ and MnO4- ?

Answer 14

KMnO4
is self indicating; the end point is
when you get the first permanent pale
pink colour.

Question 15

In a titration, what are concordant

results?

Answer 15

Titres that are within 0.1 cm3 of each

other.

Question 16

Give 3 possible sources of error in this

experiment

Answer 16

• The iron may not completely dissolve - warming
  may help
• Some iron may not be transferred between
  containers - take washings
• The end point may be hard to see - place a white
  tile underneath the conical flask to make the colour
  change easier to observe

Question 17

What equation links concentration, moles

and volume?

Answer 17

Moles = volume x concentration
n = V x C

Question 18

What equation links mass, molecular

mass and number of moles?

Answer 18

Mass (g) = molecular mass x mole

m = M x n

Question 19

What is primary research?

Answer 19

A new set of data that has been
collected. Conclusions are drawn from
this new data.

Question 20

Give two examples of primary research

Answer 20

Surveys

Experiments

Question 21

What is secondary research?

Answer 21

Data from other studies that are used to

draw conclusions

Question 22

What is the difference between

qualitative and quantitative data?

Answer 22

Qualitative - descriptions of observations

Quantitative - numerical data

Question 23

Online and offline resources can be used

for what?

Answer 23

Research

Question 24

Describe the Vancouver referencing

system

Answer 24

Full references are numbered at the end of a document (with numbers
linked to the appropriate reference in they order they appear in the text).
E.g. 1. Author (year of publication), title
Other information such as the page number, volume/ issue number, web
address or date of access (online only) may also need to be recorded.

Question 25

Describe the Parenthetical (Harvard)

referencing system

Answer 25

The authors name and the date of the work are put in brackets at
an appropriate point in the text
E.g. Universal indicator can be used to measure pH (author, date).
The references are listed at the end of the document in
alphabetical order without numbers. If there are more than 3
authors, write the first name followed by ‘et al.’.

Question 26

What is the general reference format for

books?

Answer 26

Author (year), Title, edition (if relevant),

publisher’s location, publisher

Question 27

What is the general reference format for

journal articles?

Answer 27

Author (year), ‘Article title’, Journal title,
volume number, issue number, pp.xxx-xxx
(where pp. xxx-xxx is the range of pages)

Question 28

What is the general reference format for

websites?

Answer 28

Author (year), Title. [online] Last accessed
date: URL
If the author is not listed on the webpage,
name the organisation