If the speed of light is 3.0 × 108 m s–1, then the distance covered by light in 2.00 nanoseconds will be:

1. 0.500 m

2. 0.600 m

3. 0.700 m

4. 0.800 m

Subtopic:  Introduction |
 88%
Level 1: 80%+
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In a reaction A + B2 → AB2, 
A will act as a limiting reagent if :

i. 300 atoms of A reacts with 200 molecules of B
ii. 2 moles A reacts with 3 moles B2
iii. 100 atoms of A reacts with 100 molecules of B
iv. 5 moles A reacts with 2.5 moles B
v. 2.5 moles A reacts with 5 moles B2

 
Choose the correct option:

1. (i), (ii) 2. (i), (ii), (v)
3. (ii), (v) 4. All
Subtopic:  Limiting Reagent |
 71%
Level 2: 60%+
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If 10 volumes of H₂ react completely with 5 volumes of O₂, what volume of water vapor will be produced under the same conditions of temperature and pressure?

1. 9

2. 8

3. 10

4. 11

Subtopic:  Equation Based Problem |
 88%
Level 1: 80%+
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Find the value of 15.15 pm expressed in the basic SI unit of length.

1. 1.515 × 1012 

2. 2.57 × 1011 m

3. 2.87 × 1011 m

4. 1.515 × 10–11 m

Subtopic:  Introduction |
 77%
Level 2: 60%+
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Determine the number of significant figures that should be present in the final answers for each of the following expressions:

I. 0.02856 × 298.15 × 0.112 / 5785
II. 5 × 5.364
III. 0.0125 + 0.7864 + 0.0215
 
1. 4, 4, 3 2. 3, 3, 4
3. 4, 3, 4 4. 3, 4, 4

Subtopic:  Introduction |
 62%
Level 2: 60%+
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The molar mass of naturally occurring Argon isotopes is: 

Isotope Isotopic molar mass Abundance
36-Ar  35.96755 g mol–1 0.337%
38-Ar  37.96272 g mol–1  0.063%
40-Ar  39.9624 g mol–1  99.600%
 
1. 49.99947 g mol-1  2. 39.99947 g mol-1  
3. 35.59947 g mol-1   4. 45.59947 g mol-1  
Subtopic:  Empirical & Molecular Formula |
 82%
Level 1: 80%+
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Find the mass of CaCO₃ required to completely react with 25 mL of 0.75 M HCl according to the reaction:

CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + CO₂(g) + H₂O(l)

 

1. 0.36 g

2. 0.09 g

3. 0.96 g

4. 0.66 g

Subtopic:  Concentration Based Problem | Equation Based Problem |
 65%
Level 2: 60%+
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How many grams of HCl are required to react with 5.0 g of manganese dioxide in the reaction provided?
\(4 \mathrm{HCl}_{(\mathrm{aq})}+\mathrm{MnO}_{2(\mathrm{~s})} \rightarrow 2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{l})}+\mathrm{MnCl}_{2(\mathrm{aq})}+\mathrm{Cl}_{2(\mathrm{~g})}\)


1. 4.8 g

2. 6.4 g

3. 2.8 g

4. 8.4 g

Subtopic:  Equation Based Problem |
 67%
Level 2: 60%+
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The correct match is:
List-I List-II
a. Micro i.  10-15 m
b. Mega ii.  10-6 m
c. Giga iii.  106 m
d. Femto iv.  109 m
Codes:
a b c d
1. i iv iii ii
2. iii iv ii i
3. ii iii iv i
4. i iii iv ii
Subtopic:  Introduction |
 85%
Level 1: 80%+
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The numbers 234,000 and 6.0012 can be represented in scientific notation as:
 

1. \(2.34 \times 10^{-9} \text { and } 6 \times 10^3\)
2. \(0.234 \times 10^{-6} \text { and } 60012 \times 10^{-9}\)
3. \(2.34 \times 10^{-9} \text { and } 6.0012 \times 10^{-9}\)
4. \(2.34 \times 10^5 \text { and } 6.0012 \times 10^0\)
Subtopic:  Introduction |
 83%
Level 1: 80%+
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