Question

In 1928, 47.5 g of a new element was isolated from 660 kg of the ore molybdenite. the percent by mass of this element in the ore was:

Answer 1

To take the percent by mass of this element, we use the formula:

% mass = (mass of element / mass of ore) * 100%

% mass = (47.5 g / (660 kg * 1000 g / kg)) * 100*

% mass = 7.20 x 10^-3 %

Answer 2

Answer: The mass percent of element in the ore is 0.0072 %

Explanation:

To calculate the mass percentage of element in ore, we use the equation:

$\text{Mass percent of element}=\frac{\text{Mass of element}}{\text{Mass of ore}}\times 100$

Mass of element = 47.5 g

Mass of ore = 660 kg = 660000 g    (Conversion factor:  1 kg = 1000 g)

Putting values in above equation, we get:

$\text{Mass percent of element}=\frac{47.5g}{660000g}\times 100=0.0072\%$

Hence, the mass percent of element in the ore is 0.0072 %