As the question tells you, you need to use the formula
% mass= mass of solute/ mass of solution x 100
mass solute= 30.0 g
mass of solution= 30.0 + 270.0= 300.0 g
% mass= 30.0/ 300.0 x 100= 10%
answer is B
Answer:
b. 54.9%
Explanation:
An emerald gemstone has the formula Be₃Al₂Si₁₆O₁₈. We can find the mass of each element in 1 mole of Be₃Al₂Si₁₆O₁₈ by multiplying the molar mass of the element by its atomicity.
Be: 3 × 9.01 g = 27.03 g
Al: 2 × 26.98 g = 53.96 g
Si: 16 × 28.09 g = 449.4 g
O: 18 × 16.00 g = 288.0 g
Total mass = 818.4 g
The mass percentage of silicon is:
(449.4 g / 818.4 g) × 100% = 54.91%
Answer:
1. Hydrogen will diffuse faster.
2. The ratio of diffusion of hydrogen gas to that of the unknown gas is 4 : 1
Explanation:
Let the rate of diffusion of hydrogen gas, H2 be R1
Let the molar mass of H2 be M1
Let the rate of diffusion of the unknown gas be R2.
Let the molar mass of the unknown gas be M2.
Molar mass of H2 (M1) = 2x1 =2g/mol
Molar mass of unknown gas (M2) = 16 times that of H2
= 16 x 2 = 32g/mol
1. Determination of the gas that will diffuse faster. This is illustrated below:
R1/R2 = √(M2/M1)
R1/R2 = √(32/2)
R1/R2 = √16
R1/R2 = 4
Cross multiply
R1 = 4R2
From the above calculations, we can see that the rate of diffusion H2 (R1) is four times the rate of diffusion of the unknown gas (R2).
Therefore, hydrogen will diffuse faster.
2. Again, from the calculations made above, the ratio of diffusion of hydrogen (R1) to that of the unknown gas (R2) is given by;
R1/R2 = 4
Therefore, the ratio of diffusion of hydrogen (R1) to that of the unknown gas (R2) is:
4 : 1
