Oquizy

John calculates the Rf as 1.25. What does this indicate?

Correct result Spot moved further than solvent front The ink dried too quickly The solvent was too slow

John measures the boiling point of an unknown liquid and finds it boils between 72°C and 76°C. Which statement is false?

It can be a solid at room temperature It is a mixture Its melting point is 43°C The substance is pure

Rf value of an unknown spot is 0.72. Compare to reference Rf list:
Glucose: 0.50
Caffeine: 0.72
Ethanol: 0.95
What is the likely substance?

Caffeine Ethanol Glucose Mixture

In an experiment to investigate how temperature affects the rate of reaction, which is the independent variable?

Temperature of solution Time measured Type of acid used Volume of gas produced

If a different solvent is used in chromatography, what happens to the Rf values?

All Rf values increase Rf values decrease to zero Rf values may change depending on solubility Rf values remain unchanged

John is heating ethanol with a Bunsen burner. What is the most important safety precaution?

Boil it quickly for accuracy Use a strong tripod Use a water bath Wear cotton gloves

Quiz: Chemistry - Experimental Chemistry