Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution [NaOH = 40 g mol]
0.0156 g
0.625 g
1.00 g
25.0 g
Correct answer is D
1 mole of NaOH per dm3 has a mass of 40g mass of NaOH in 0.125 mole = 0.125 x 40 = 5g mass in 5.00 dm3 of the solution = 5 x 5 = 25.0g
Which of the following substances increases in mass when heated in air?
Sodium chloride
lodine crystals
magnesium ribbon
copper (ll) oxide
Correct answer is C
No explanation has been provided for this answer.
A substance is said to be hygroscopic if it absorbs?
water from the atmosphere to form a solution
heat from the surrounding
carbon (IV) oxide from the atmosphere
moisture from the atmosphere without dissolving
Correct answer is D
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment,
which is usually at normal or room temperature.
Deliquescence, the process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water and forms a solution.
Which of the following acids forms normal salts only?
Tetraoxosulphate (VI) acid
Trioxosulphate (IV) acid
Tetraoxophosphate (V) acid
Trioxonitrate (V) acid
Correct answer is D
No explanation has been provided for this answer.
A major factor coonsidered in selecting a suitable method for preparing a simple salt is its
crystalline form
melting point
reactivity with dilute acids
solubility in water
Correct answer is D
No explanation has been provided for this answer.