SAFETY
What should you wear whenever you are heating a liquid?
Goggles should be worn.
What is the name given to a variable that must remain the same during an experiment?
A controlled variable.
Where do you write the results of an experiment?
In a table.
What should be excluded from the calculation of the mean?
Any error or anomalous reading.
Why it is not a good idea to use a beaker to measure a volume?
Because beakers are not very accurate.
The use of which apparatus requires hair to be tied and goggles to be worn?
The Bunsen burner
What is the name given to the variable you manipulate or vary in an experimental study to explore its effects?
The independent variable.
In a table, where should you write the units?
In the headings of the table/ in the column headers (the top part)
What can be done to spot and discard anomalous readings?
Taking repeated measurements.
Instead of using a Bunsen burner, what could you use to heat up a solution at a specific temperature?
A thermostatic water bath.
Which hazard symbol is represented by red triangle/diamond surrounding a skull?
Toxic/poison hazard.
Which apparatus should be used to accurately deliver a volume of solution during titration?
What is the name given to the type of data that can be measured?
Quantitative data.
On which axis of a graph, should the values of the independent variable be located?
The x-axis.
Which type of thermometer has a better accuracy than alcohol thermometers?
Mercury thermometers.
What is the name given to any chemical substance capable of causing harm to a person or the environment?
A chemical hazard
Which apparatus can be used to quickly, simply and accurately measure a volume, but is less accurate than a burette?
The measuring cylinder.
Give an example of qualitative data.
A colour change, the formation of a precipitate, smell...
In a graph, what is an ''outlier''?
It is a data point that doesn't fit the pattern shown by the other points on the graph.
In general, at least how many times should an experiment be repeated? and how many different values of independent variable should be investigated?
The experiment should be repeated at least 3 times (or 3 readings), and 5 different values of independent variable should be investigated at least.
Why you should never add water to a strong acid?
because the solution will heat up and the strong acid may spill out of the container.
What is the difference between precision and accuracy?
Precisions: how close to each other are repeated measurements.
Accuracy: how close a measurement is to the real value.
During a titration, how is the end-point usually observed?
when a coloured indicator changes colour
What is the formula to calculate the slope of a graph?
slope = rise/run = (Y2 - Y1)/(X2 - X1)
In exam, when asked about ways to improve an experiment what can be a standard answer?
Repeat the experiment AND calculate the mean.