Question

1) 1.5 moles of O2 combine with Mg to form oxide MgO. The mass of Mg that has combined is ___

2) The quantity of lime stone that on heating will give 56kg of CaO is​

Answer 1

1)

Given:

• 1.5 Moles of O2 combines with Mg

Need to find:

• The mass of Mg=?

Answer:

Let the amount of Mg be x

O2+2Mg------> 2MgO

1.5mol+2x -------> 2x

we can say,

2x= 2×1.5mol

=> x= 3mols

we know,

1 mol= 24g (mass of 1 mol of Mg)

thus

3mol= 3×24g

=72g (ans)

━━━━━━━━━━━━━━━━━━━

CaCO3-------> CaO+ CO2

Mass of CaO= 56amu

CaO= 56kg

=56000÷56 mol

= 1000mol

CaCO3,

1mol= 100g

1000mol = 100× 1000g

= 100000g

=100kg (ans)