Question

Question

The mass of a dust particle is approximately 7.5×10−10
kilograms and the mass of an electron is 9.1×10−31
kilograms. How many electrons does it take to equal the mass of a dust particle?(1 point)
Responses

8.2×10−20
8 point 2 times 10 to the negative 20 power

1.2×10−21
1 point 2 times 10 to the negative 21 power

6.8×10−41
6 point 8 times 10 to the negative 41 power

1.2×1021
1 point 2 times 10 to the 21th power

6.8×10−40
6 point 8 times 10 to the negative 40 power

8.2×1020

Answer 1

To find out how many electrons it takes to equal the mass of a dust particle, you can divide the mass of the dust particle by the mass of an electron:

\[ \text{Number of electrons} = \frac{\text{Mass of dust particle}}{\text{Mass of an electron}} = \frac{7.5 \times 10^{-10} \text{ kg}}{9.1 \times 10^{-31} \text{ kg}} \]

Now, calculating this:

\[ = \frac{7.5}{9.1} \times \frac{10^{-10}}{10^{-31}} = 0.8258 \times 10^{21} \approx 8.26 \times 10^{20} \]

So, it takes approximately \( 8.2 \times 10^{20} \) electrons to equal the mass of the dust particle.

The correct response is:

8.2×10^20 (8 point 2 times 10 to the 20th power)