The nucleus of the isotopes tritium,contains
two neutrons with no protons
one neutron and one proton
two neutrons and one proton
two neutrons, one proton and one electron
Correct answer is C
No explanation has been provided for this answer.
400k
480k
550k
600k
Correct answer is D
No explanation has been provided for this answer.
The fraction of crude oil used as jet fuel is
refinery gas
diesel oil
kerosine
gasoline
Correct answer is C
No explanation has been provided for this answer.
At 25oC and 1atm, a gas occupies a volume of 1.50dm3. What volume will it occupy at 100oC and 1atm?
1.88 dm3
6.00 dm3
18.80 dm3
18.80 dm3
60.00dm3
Correct answer is A
\(\frac{v_1}{T_1} = \frac{V_2}{T_2}\)
V2 = \(\frac{V_1 \times T_2}{T_1}\)
= \(\frac{1.50 \times 373}{298}\)
= 1.88 dm3
The dissolution of common salt in water is a physical change because
the salt can be obtained by crystallization
the salt can be recovered by the evaporation of water
heat is not generated during mixing
the solution will not boil at 100oC
Correct answer is B
The evaporation of water is a physical change. When water evaporates, it changes from the liquid state to the gas state, but it is still water; it has not changed into any other substance.