GCSE -> A LEVEL Qs Flashcards
Transition booklet question
When is a measurement valid?
When it measures what it is supposed to be measuring.
When is a result accurate?
When it is close to the true value.
What are precise results?
When repeat measurements are consistent/agree closely with each other.
What is repeatability?
How precise repeated measurements are when they are taken by the same person, using the same equipment, under the same conditions.
What is reproducibility?
How precise repeated measurements are when they are taken by different people, using different equipment.
What is the uncertainty of a measurement?
The interval within which the true value is expected to lie.
Define measurement error.
The difference between a measured value and the true value.
What type of error is caused by results varying around the true value in an unpredictable way?
Random error
What is a systematic error?
A consistent difference between the measured values and the true values.
What does zero error mean?
A measuring instrument gives a false reading when the true value should be zero.
Which variable is changed or selected by the investigator.
Independent variable
What is a dependent variable?
A variable that is measured every time the independent variable is changed.
Define a fair test.
A test in which only the independent variable is allowed to affect dependent variable.
What are control variables?
Variables that should be kept constant to avoid them affecting the dependent variable
What are monomers?
Smaller units with larger molecules are made.
What are polymers?
Molecules made from a large number of monomers joined together
What is a condensation reaction?
A reaction that joins two molecules together to form a chemical bond whilst eliminating of a molecule of water.
What is a hydrolysis reaction?
A reaction that breaks a chemical bond between two molecules and involves the use of a water molecule.
What is a monosaccharide?
Monomers from which larger carbohydrates are made.
How is a glycosidic bond formed?
A condensation reaction between two monosaccharides.
Name the three main examples of polysaccharides.
Glycogen, starch, cellulose
Describe Benedict’s test for reducing sugars.
Gently heat a solution of a food sample with an equal volume of Benedict’s solution for five minutes, the solution turns orange/brown if reducing sugar is present.
Name the two main groups of lipids.
Phospholipids, triglycerides (fats and oils)
Give four roles of lipids.
Source of energy, waterproofing, insulation and protection.
