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1. What is the correct number of significant figures in the following calculatio

ID: 486455 • Letter: 1

Question

1. What is the correct number of significant figures in the following calculation?

2. Which of the following ionic isotopes has the same number of neutrons and electrons?

a)75Br-1

b)77Y+1

c)25Al+3

d)33Zn+3

3.I would like to add carpet to all the floors in my house. If all the floors in my house measure 1,865 ft2, and the cost of carpet is $39.87 per m2, how much would it cost to cover my floors with carpet?

4. Copper has two isotopes, 63Cu and 65Cu. If the isotopic mass of 63Cu is 62.9296 amu, the isotopic mass of 65Cu is 64.9278 amu, and the atomic mass of Copper is 63.5462 amu, what is the % abundance of each isotope of copper?

5. Please fill in the missing information

Name Molecular Formula

Iron (III) Chloride _______________

______________ RuO3

Magnesium Nitride _______________

_______________ N3F5

Copper(I) Sulfide ________________

2.574 (21.84 -20.78) (25.478 5468) 7.125

Explanation / Answer

1)

21.84 - 20.78 = 1.06

2.574/1.06= 2.43 (leat of the significant figure)

25.478 - 0.5468 = 24.931

24.931/7.125 = 3.499

so finally we have,
2.43 * 3.499 = 8.50

number of significant figure should be 3

Answer: 3

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