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.
1.00 X 10\(^{23}\)
6.02 X 10\(^{23}\)
6.02 X 10\(^{22}\)
6.02 X 10\(^{24}\)
Correct answer is C
1 mole of CaCO\(_3\) = 100g or 6.02 X 10\(^{23}\)
liberated 1 mole of CO\(_2\) or 44g or 6.02 X 10\(^{23}\)
:100g = 6.02 X 10\(^{23}\)
10g of CaCO\(_3\) = x
cross multiply
[10g X 6.02 X 10\(^{23}\)] / 100g = x
⇒ x = 6.02 X 10\(^{22}\)
Since
6.02 X 10\(^{23}\) of CaCO\(_3\) liberated 6.02 X 10\(^{23}\) of CO\(_2\)
⇒ 6.02 X 10\(^{22}\) of CaCO\(_3\) will liberate 6.02 X 10\(^{22}\) of CO\(_2\)
How many valence electrons are contained in the element \(^{31}_{15}P\)?
3
4
15
31
Correct answer is A
The element is Phosphorus in group 5 with valencies of 3 and 5.
The products of the thermal decomposition of ammonium trioxonitrate(v) are?
Nitrogen (I) Oxide and Water
Ammonia and Oxide
Nitrogen and Water
Nitrogen (IV) Oxide and Water
Correct answer is A
NH\(_4\)NO\(_3\) Ammonium Trioxonitrate(V) , unlike all other metallic trioxonitrates(v), decomposes on heating to give nitrogen(i)oxide N\(_2\)O and water.
P
Q
R
S
Correct answer is B
They are the most stable due to having the maximum number of valence electrons their outer shell can hold. Therefore, they rarely react with other elements since they are already stable.
1.650atm
0.825atm
0.413atm
0.275atm
Correct answer is A
Using the combined gas law formula,
Given that P\(_1\) = 0.825, V\(_1\) = 2.76 L, V\(_2\) = 1.38 L, P\(_2\) = ?
And T1 = T2; we would have P\(_2\) = [ P\(_1\) X V\(_1\) ] ÷ V\(_2\)
: [0.825 X 2.76] ÷ 1.38
= 1.650atm