Answer:
179.0 g of iridium (1 mol / 192.217 g) ( 6.022 x 10^23 atoms / 1 mol ) = 5.61 x 10^23 atoms of iridium
Explanation:
To determine the mass of CO₂, the following must be known :
- the molar mass of CaCO₃
- the mole ratio of CaCO₃ to CO₂
- the molar mass of CO₂
<h3>Further explanation</h3>
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Decomposition of CaCO₃
CaCO₃ ⇒ CaO + CO₂
Given the mass of CaCO₃, so to determine the mass of CO₂ :
1. Find the mol of CaCO₃ from the molar mass of CaCO₃

2. Find the mole ratio of CaCO₃ : CO₂(from equation = 1 : 1)

3. Find the mass of CO₂ from the molar mass of CO₂

The mass of pentane the student should weigh out is
The density of pentane is 0.626 gcm-3
To calculate the mass of pentane following expression is used,
(Density is defined as the mass divide by volume)
Density = mass / volume
mass of pentane = Density of pentane * Volume of pentane
mass of pentane = 0.626 gcm-3 * 45.0 mL
= 28.17 g
Here the unit of mass of pentane is g,
However the unit of density is gcm-3 and unit of volume is mL i.e. cm3
Hence, Mass = gcm-3 * cm3
Mass = g
The mass of pentane the student should weigh out is 28.17g
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