Formulate a research question, identify independent, dependent and controlled variables, and design or improve a method so that it answers the question fairly and safely.
(c) A simple set-up was used to compare the conductivity of water samples obtained from the Salton Sea at different depths. The following data were obtained: Depth water sample was obtained from / m () Electric current recorded by the…
A sample of 0.0120 mol of was placed in a sealed vessel of volume 1.00 , which was kept at a constant temperature of 35 °C. (i) Suggest a simple way of keeping the vessel at a constant temperature in a school laboratory. (ii) The…
(i) State the independent variable and the dependent variable of the investigation. (ii) Apart from the mass of leaves and the volume of water, suggest two other conditions that should be kept constant for the comparison between boiling times to be valid.…
Each beaker used as a chromatography chamber was covered with a watch glass while the solvent rose up the paper. Explain why the chamber has to be covered for the experiment to be properly designed.
The student suspected that the ink contained more than four dyes, and that one of the spots was two dyes that had not separated. Suggest how the student could modify the chromatography experiment to test this idea.
Identify two controlled variables in this investigation.
The student measures the hydrogensulfite concentration by titrating samples against a standard iodine solution, with starch as the indicator. Every three days, 25.00 of cordial is withdrawn from each flask, diluted to 250.0 with…
Suggest one way of extending the investigation so that it could lead to additional advice on storing cordial.