Question

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1. How many moles are there in 11.2 g of Fe? (Fe=56)
2. Calculate the mole number in 57.6 g of Ti2O3. (Ti=48, O=16)
3. What is the mole number of 196 g Cr2(SO4)3? (Cr=52, S=32, O=16)
4. 1.5 mol of compound Mg3X2 has mass 150 g. What is the atomic mass of element X? (Mg=24)
5. 0.15 mol of compound Ca3(XO4)2 has mass 59.7 g. What is the atomic mass of element X in the compound? (Ca=40, O=16)

Answer 1

Explanation:

Correct option is B)

Molar mass of Cr

2

S

3

=(2×52)+(3×32)=104+96=200 g

Therefore, 200 g of Cr

2

S

3

has (2×52) g of Cr

So, 85 g of Cr

2

S

3

will have =

200

85×2×52

=44.2 g

Moles of Cr in Cr

2

S

3

=

104 g

44.2 g

=0.85