Which of the following gases will rekindle a brightly splint?
NO\(_2\)
NO
N\(_2\)O
CL\(_2\)
Correct answer is C
Nitrogen(I)Oxide rekindles a brightly glowing splinter but extinguishes a feebly glowing one which is not hot enough to decompose the gas to liberate oxygen
28
32
44
71
Correct answer is D
500cm\(^3\) of the gas weighed 1.58
: 22400cm\(^3\) of the gas weight
[22400 X 1.58g] ÷ [ 500 ]
= 71
49,000
48,000
31,000
30,000
Correct answer is C
Trading profit and Loss Account
|
opening stock 4,000 Gross profit 31,000 |
Sales 50,000 G.profit b/d 31000 |
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.