Experimental Know-How Flashcards Preview

Grace Chemistry IGCSE > Experimental Know-How > Flashcards

Flashcards in Experimental Know-How Deck (12)
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1
Q

Reliable results

A

give the same data each time the experiment by you and reproduced by other scientists

2
Q

Valid results

A

Reliable

Fair test

3
Q

Control variables

A

Temperature
Concentration of reactants
Volume of reactants
Mass of reactants

4
Q

How to improve reliability

A

Repeat

Mean average

5
Q

Potential hazards

A

Chemicals (gloves, safety goggles to reduce risk of the acid on skin or in eyes)
Fire (heat proof mat to reduce risk of starting fire)
Electricity
Fumes (fume cupboard)

6
Q

Accuracy

A

Human error
Measuring the right thing, don’t include anything you shouldn’t
Impurities
Reaction unfinished -> not all the product produced
Heat escaped into atmosphere
Gas syringe -> empty at start
Small increments

7
Q

Precise

A

Close to the mean average

Use a sensitive instrument that can measure small increments

8
Q

What are anomalous results caused by?

A

Human error (mistake when measuring, not using equipment correctly)
Is it too high or too low? What’s caused that?
When calculating average, ignore

9
Q

What can cause a correlation?

A
  • chance
  • linked by a 3rd variable
  • cause
10
Q

How to calculate rate from a graph

A

Gradient

Δy/Δx

11
Q

Gradient of a curve

A

Draw tangent

12
Q

Evaluations

A

Valid? Fair test?
Enough results taken?
Reliable? Accurate? Precise?
Anomalous results?