Basic Facts
Feeling Accurate or Reliable?
Aims/ Variables/ Hypothesis
Good Method?
Conclude my Graphs
100
Lemon juice would be this colour when mixed with universal indicator.
What is red/ orange.
Lemon juice has a pH of around 2-3.
100
Define accuracy in an experiment.
What is the recorded results are close to the true/accepted value for what is being measured.
accurate = actual value
Refers to how carefully and correctly you take your measurements. You can improve accuracy by reducing errors.
100
Name the three types of variables to consider in an experiment/ investigation.
What is the independent variable, dependent variable, control variable.
100
Could the scientist improve their method?
What is safety googles.
Also accepted bare legs, use of graduated cylinder.
SAFETY IS #1 most important step in any lab method.
100
What is missing from the graph.
What is axes labels with units.
Independent variable on x axis.
Dependent variable on y axis.
200
These ions are responsible for acidity and alkalinity.
BONUS 100
State the process molecules undergo to break into their ions.
What are H⁺ (hydrogen) ions for acids and OH⁻ (hydroxide) ions for bases.
BONUS
What is dissociation.
200
Look at the target. State what the results are.
What is reliable (precise) but not accurate.
200
Define one of the variable types in an experiment/ investigation.
BONUS 100
for every extra variable defined
Independent: What you will change.
Dependent: What you will measure.
Controlled: What you will keep the same to make sure you have a fair test.
200
There is a basic solution in a graduated cyliner. What is the volume and where do you stand to do this. Assume it is in mL.
What is 2.65mL at eye level.
200
Circled in red is a(n) ____________.
BONUS 100
In an experiment, should you include this data point in your trend line calculation?
What is an anomaly or outlier.
BONUS: No.
300
The general equation in words of a neutralisation reaction with a metal hydroxide.
Acid + Base → Salt + Water.
300
Look at the target. State what the results are.
What is accurate but not reliable (precise).
300
This type of experiment/ investigation only changes one variable. All other variables are kept the same.
What is a fair test
300
What is the mistake for the given method for making brownies.
What is not written in numbered steps.
Also accepted, there is no separate equipment list.
300
The average number of drops of NaOH needed to neutralise Acid D.
What is 100.
400
The products formed from the reaction of sodium hydroxide + hydrochloric acid.
BONUS 100
If you write both words and formulas (both need to be correct for points!)
What is Sodium Chloride (NaCl) and Water (H2O).
table salt and water also acceptable.
400
A _____ test is an experiment which is carefully controlled to ensure that the information gathered is _________. To make an experiment ________ we change only one factor at a time while keeping all other conditions the same.
What is fair, reliable, accurate.
400
Given the aim:
"To determine how many drops of sodium hydroxide (base) is required to neutralise each unknown acid."
State the dependent and indepedent varaibles.
Independent variable: type of acid (what you are changing)
Dependent variable: number of drops of NaOH (what you are measuring)
400
The first 4 steps of a method are shown for making salt. Name the error.
What is a piece of equipment used in the method is not listed on the equipment list (the spatual).
400
Given the results table from a neutralisation experiment, would the first 3 trails be adequate to gather reliable data to plot?
BONUS 200
State why or why not
What is no.
BONUS
4 trails were needed as there was outlier data that was gathered in the first 3 trails of Acid A, C, D, E.
500
Scuba divers use rebreathers to neutralise and scrub out CO2 from their breathing apparatus using soda lime, Ca(OH)2 as a base.
Write the chemical equation.
BONUS 200
What is the name of the salt formed?
Ca(OH)₂ + CO₂ → CaCO₃ + H₂O
BONUS 200
Calcium carbonate.
500
Ms. Len wants to test whether bee stings are acidic and wasp stings are alkaline. Every time she lets a bee sting her arm, the bee dies, so she can only test one bee, while the wasp can sting multiple times. How does this limitation affect the reliability of her experiment?
Reliablility is low. She can’t repeat the bee sting test multiple times.
Also can say reliability seems okay for wasps but not for bees.
500
Write a hypothesis given the following aim:
"To investigate the effect of temperature on the rate at which sugar cubes dissolve in water."
I think that as the temperature of the water is increased, the sugar cubes will dissolve faster. I think this because higher temperatures increase the kinetic energy of water molecules, causing them to collide with the sugar more frequently.
Need a because to get the points.
500
Mr. Herber is performing an experiment that Ms. Len has written. Following her method, he completes step 3 that states:
"Step 3: Carefully measure out 3mLs of HCl 1 mol acid and pour into a clean and dry 250mL beaker."
Was this step well explained? Y/N. State WHY.
"Carefully measure" subjective language. Use a measuring cylinder.
WHY?
Measuring cylinder allows for more exact/ precise amounts to be measured for every trail of every acid. This will help create more accurate results as acid measurements will be as close to the true value stated in the method as possible.
500
We have two sets of data. Which is more reliable and why?
Data set on the right is more reliable since it has many more trails. More repeats = larger amount of data to base your conclusion off of.