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.
When ammonium, potassium and calcium carbonates are each separately heated
none of them will decompose
each of them will decompose to give carbondioxide and the respective oxide
ammonium carbonate and potassium carbonate will not decompose
only ammonium carbonate and the respective oxide
ammonium carbonate will decompose to give carbondioxide, water and ammonia
Correct answer is E
Solid ammonium carbonate decomposes as it is heated.
(NH4)2CO3 → 2 NH3 + CO2 + H2O
How many grams of HBr would exactly be required to react with 2 g of propyne? (C =12, H=1, Br = 80)
4.1g
6.1g
8.1g
16.2g
Correct answer is C
2HBr + C3H4 \(\to\) C3H6 + 2Br
162gms of HBr reacts with 40gms of propyne 2gms of propyne will react with
\(\frac{162}{40} \times \frac{2}{1}\) = 8.1gms HBr
50 cm3
10 cm3
40 cm3
30 cm3
70 cm3
Correct answer is A
The equation of the reaction is:
\(2H_{{2}{(g)}} + O_{{2}{(g)}} = 2H_{2}O_{(g)}\)
Before Sparking we have : \(50cm^{3} : 20cm^{3}\)
On Sparking, \(40cm^{3} : 20cm^{3} : 40cm^{3}\)
After Sparking, we have \(10cm^{3} : 0 : 40cm^{3}\)
Hence, the volume of residual gases = \((10+40)cm^{3} = 50cm^{3}\)
Helium atoms are chemically unreactive because
there are no electrons around the nucleus
the number of protons equals the number of electrons
there are equal number of protons and neutrons in the nucleus
the outer electron shell is completely filled
the atoms contain only protons
Correct answer is D
No explanation has been provided for this answer.
Which of the following contains two amphoteric oxides?
sodium oxide, Zinc oxide , Magnesium oxide
Aluminium oxide, Calcium oxide, Zinc oxide
Potassium oxide, Lithium oxide, Carbon monoxide
Silver oxide, Lead oxide, Sodium oxide
Sulphur dioxide, Aluminium oxide, Carbon monoxide
Correct answer is B
No explanation has been provided for this answer.