(a) How many significant figures are there in the following: (i) 0.00

1.	(a) How many significant figures are there in the following: (i) 0.0026 (ii) 6.022 × 1013 (b) Calculate the number of carbon atoms is 34.20 g of C6H12O6.
Answer» (a) (i) 0.0026 = 2.6 × 10^–3 It has two significant figures. (ii) 6.022 × 10¹³ It has four significant figures. (b) Number of particles in a mole = 6.023 × 10²³ Molecular mass of C₆H₁₂O₆ = 180 Number of carbon atoms = 6 \(\therefore\) 180 g of C₆H₁₂O₆ contains = 6 × 6.023 × 10²³ carbon atoms \(\frac{6\times6.023\times10^{23}\times34.20}{180}\) = 6.866 × 10²³carbon atoms

(a) How many significant figures are there in the following: (i) 0.0026 (ii) 6.022 × 1013 (b) Calculate the number of carbon atoms is 34.20 g of C6H12O6.

Answer»

(a) (i) 0.0026 = 2.6 × 10^–3

It has two significant figures.

(ii) 6.022 × 10¹³

It has four significant figures.

(b) Number of particles in a mole = 6.023 × 10²³

Molecular mass of C₆H₁₂O₆ = 180

Number of carbon atoms = 6

\(\therefore\) 180 g of C₆H₁₂O₆ contains

= 6 × 6.023 × 10²³ carbon atoms

\(\frac{6\times6.023\times10^{23}\times34.20}{180}\)

= 6.866 × 10²³carbon atoms