# chemistry

posted by .

In a 100g sample of copper, 69 g were Cu-63 while 31g were Cu-65. Find the average atomic mass.

• chemistry -

To obtain an exact number you need the masses of each isotope (they won't be 63 and 65). In the absence of that, however, you substitute those numbers for the 63 and 65 in my answer and you will obtain the correct atomic mass.
(0.69*63) + (0.31*65) = ?

## Similar Questions

1. ### Chemistry

The element copper, found in nature with an average atomic mass of 63.54u, consists of two isotopes, copper-63 of atomic mass 62.93u and copper-65 of atomic mass 64.93u. Calculate the abundance of each isotope. I can't come up with …
2. ### chemistry

The element copper has naturally occuring isotopes with mass numbers of 63 and 65. The relative abundance atomic masses are 69.2% for mass=62.93 amu, and 30.8% for mass=64.93 amu. Calculate the average atomic mass of copper.
3. ### physical science 8th grade

Copper has 2 known isotopes: ^63CU atomic mass= 62.9298 and ^65 CU atomic mass=64.9278. The average atomic mass of copper is 63.546 amu. Calculate the fraction(percent) of each of the 2 isotopes of copper
4. ### Chemistry

Naturally occurring copper contains a mixture of 69.09% copper-63 (63.9298 amu) and 30.91% copper-65 (64.9278 amu). What is the average atomic mass of copper?
5. ### Chemestry

What is the relative atomic mass of naturally occuring copper to four decimal places when you are given 69,09% of copper-63 with a relative atomic mass of 62,9298 with 30,91% of copper-65, with a relative atomic mass of 64,9278?
6. ### Chem

What is the volume V of a sample of 3.40mol of copper?
7. ### Chemistry

12) Naturally occurring argon is composed of 0.3365% of 36Ar (atomic mass, 35.9675 u), 0.0632% of 38Ar (atomic mass, 37.9627 u), and 99.6003% of 40Ar (atomic mass, 39.9624 u). Use these data to calculate the average atomic mass of …
8. ### Chemistry

Suppose 0.500 g of sulfur combines with 1.00 g of copper. What is the empirical formula of the compound?
9. ### Chemistry

A naturally occuring sample of copper consists of 69.2% of Cu63 and 30.8% of Cu65.The relative atomic mass of Cu63 is 62.93 and that of Cu65 is 64.93.Find the atomic mass of a naturally occuring sample of copper.
10. ### Chemistry

The atomic mass of CU 63 is 62.9296 amu with a natural abudance of 0.692. The average mass of copper is 63.546amu.What is the mass of copper's other isotope?

More Similar Questions