When repeated measurements of the same quantity are very close to one another they are

When repeated measurements of the same quantity are very close to one another they are termed as precise measurements.

Explanation:

An experiment is repeated two to three times and the outcomes were checked to have similar values to attain precision of the measurements. The accuracy and precision are the important in attaining correct measurements.

The accuracy is the closest true value obtained from the measuring instrument. But to get precise results, the measurements were taken repeatedly and then analyzed whether the values obtained are similar or varying significantly.

If the repeatedly measured values are very close to one another that means the measured quantities are precisely taken. All the values are precise in nature.

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

1.43 x 10^-11 j the guy commented the awnser just making sure u see it .