What is the molar mass of a substance, if 0.4 mole of the substance has a mass of 25.0g?
62.5 g
40.0 g
6.3 g
2.5 g
Correct answer is A
0.4 → 25
1 mole → ? = 1/0.4 * 25/1 = 250/1 = 62.5 g
Nuclear fission involves the splitting of a heavy element into two nuclei of
nearly equal masses with a relaese of energy and radiaton
equal masses with a relaese of energy
equal masses with a release of energy and radiation
unequal masses without any relaese of energy
Correct answer is A
No explanation has been provided for this answer.
The volume of 2.5 moles of oxygen at s.t.p is
[Molar volume of a gas at s.t.p = 22.4 dm3]
50.0 dm3
84.0 dm3
28.0 dm3
28.0 dm3
Correct answer is D
1 mole of gas at s.t.p = 22.4
2.5 moles → 2.5 * 22.4 = 56.00 dm3
A difference between chemical and physical change is that in a chemical change
oxygen is consumed
heat is supplied
a reversible process oocurs
a new substance is formed
Correct answer is D
No explanation has been provided for this answer.
A particle that contains 11 protons, 12 neutrons and 10 electrons is probably a
neutral non-metal
metallic ion
non-metallic ion
neutral metal
Correct answer is B
No explanation has been provided for this answer.