To calculate the mass of a piece of manganese, we can use the following formula:
\[ \text{Mass} = \text{Density} \times \text{Volume} \]
We are given that:
- The density of manganese (\( \rho \)) is 7.47 g/cm³
- The volume (\( V \)) of the piece of manganese is 40 cm³
Now let's put the values into the formula:
\[ \text{Mass} = 7.47 \, \text{g/cm}^3 \times 40 \, \text{cm}^3 \]
When we multiply these together:
\[ \text{Mass} = 298.8 \, \text{g} \]
So, the mass of the 40 cm³ piece of manganese is 298.8 grams.
The correct answer is OA. 298.8g.
