Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
The heat of reaction can be determined experimentally using a device called a
Calorimeter
Barometer
Spectrometer
Thermometer
Correct answer is A
A calorimeter is a device used to measure the heat of reaction experimentally. It is designed to isolate the reaction from the surroundings and measure the temperature change in the surroundings to calculate the heat exchanged.
What is the mass (in grams) of 500 mL of ethanol? (density of ethanol = 0.789 g/mL)
394.5 mL
500 mL
394.5 g
500 g
Correct answer is C
To calculate the mass of a substance, we can use the formula:
Mass = Volume x Density
Given the volume of ethanol is 500 mL and the density of ethanol is 0.789 g/mL, we can plug the values into the formula:
Mass = 500 mL x 0.789 g/mL = 394.5 g
Which of the following substances is NOT hygroscopic?
Salt
Sugar
Silica gel
Aluminum
Correct answer is D
Aluminum is not hygroscopic. It does not have a strong affinity for water vapor and does not absorb moisture from the air.
Which of the following mixtures is an example of a colloid?
Milk
Orange juice
Saltwater
Sugar dissolved in water
Correct answer is A
A colloid is a type of mixture where one substance is dispersed in another in the form of tiny particles that do not settle out. In milk, fat globules are dispersed in water, forming a colloid.
Why is water often referred to as the "universal solvent"?
Water is the most abundant substance on Earth
Water is essential for all living organisms.
Water is involved in many chemical reactions
Water can dissolve a wide variety of substances due to its polar nature
Correct answer is D
Water is often referred to as the "universal solvent" because of its ability to dissolve a wide range of substances. This unique property is mainly due to water's polar nature. Water molecules have a slightly positive charge on the hydrogen atoms and a slightly negative charge on the oxygen atom, making it a polar molecule. This polarity allows water molecules to interact with and surround other polar and ionic substances, breaking them down and forming solutions.