Test Index

JAMB Chemistry 2018 Paper

© africaexams.com

Question : 32

Total: 87

How many atoms are present in 6.0g of magnesium? [Mg = 24, N.A = 6.02 x 10

^{23}

mol]

1.20 x 10 $^{22}$
2.4 x 10 $^{22}$
1.51 x 10 $^{22}$
3.02 x 10 $^{22}$

Solution:

Concept:

Number of atoms = moles

\times

Avogadro's constant.

Explanation:

Moles of Mg

= \frac{6.0}{24} = 0.25

mol.

Number of atoms

= 0.25 \times 6.02 \times 10^{23} = 1.505 \times 10^{23}

atoms.

Rounded:

1.51 \times 10^{23}

atoms.

Answer:

1.51 \times 10^{23}

atoms.

The printed options are inconsistent; option C is the intended choice if its exponent is

10^{23}

.

© africaexams.com

Go to Question:

Prev Question

Next Question