Question

Calcule a massa, em gramas, segundo o exemplo abaixo:
Dado: Constante de Avogadro – 1 mol possui 6,02.1023 moléculas
a) 6,02.1022 moléculas de NaOH
b) 18,03.1023 moléculas de K2CO3
c) 6,02.1023 moléculas de HBr
d) 12,04.1024 moléculas de H2O
e) 12,04.1023 moléculas de CO2

Answer 1

Resposta:

a) 6,02 × 10²² moléculas de NaOH:

Na = 23g/mol

O = 16g/mol

H = 1g/mol

NaOH = 40g/mol

6,02 × 10²³ ---- 40g

6,02 × 10²² ---- X

X = 6,02 × 10²² × 40 ÷ 6,02 × 10²³

X = 240,8 × 10²² ÷ 6,02 × 10²³

X = 40 × 10⁻¹

X = 4g

b) 18,03 × 10²³ moléculas de K₂CO₃

K = 39g/mol

C = 12g/mol

O = 16g/mol

K₂CO₃ = 140g/mol

6,02 × 10²³ ---- 140g

18,03 × 10²³ --- X

X = 18,03 × 10²³ × 140 ÷ 6,02 × 10²³

X = 2524,2 × 10²³ ÷ 6,02 × 10²³

X = 419,3

c) 6,02 × 10²² moléculas de HBr

H = 1g/mol

Br = 80g/mol

HBr = 81g/mol

6,02 × 10²³ ---- 81g

6,02 × 10²² ---- X

X = 6,02 × 10²² × 81 ÷ 6,02 × 10²³

X = 487,62 × 10²² ÷ 6,02 × 10²³

X = 81 × 10⁻¹

X = 8,1g

d) 12,04 × 10²⁴ moléculas de H₂O

H = 1g/mol

O = 16g/mol

H₂O = 18g/mol

6,02 × 10²³ ---- 18g

12,04 × 10²⁴ --- X

X = 12,04 × 10²⁴ × 18 ÷ 6,02 × 10²³

X = 216,72 × 10²⁴ ÷ 6,02 × 10²³

X = 36 × 10¹

X = 360

e) 12,04 × 10²³ moléculas de CO₂

C = 12g/mol

O = 16g/mol

CO₂ = 44g/mol

6,02 × 10²³ ---- 44g

12,04 × 10²³ --- X

X = 12,04 × 10²³ × 44 ÷ 6,02 × 10²³

X = 529,76 × 10²³ ÷ 6,02 × 10²³

X = 88g

Bons estudos. :)