There are 1.48 × 10²⁵ molecules of zinc oxide in a 2 kg sample. Details about number of molecules can be found below.
<h3>How to calculate number of molecules?</h3>
The number of molecules of a substance can be calculated by multiplying the number of moles of the substance by Avogadro's number.
According to this question, there are 2000g of ZnO in a sample. Zinc oxide has a molar mass of 81.38 g/mol.
no of moles = 2000g ÷ 81.38g/mol
no of moles = 24.57mol
number of molecules = 24.57 × 6.02 × 10²³
number of molecules = 147.95 × 10²³
Therefore, there are 1.48 × 10²⁵ molecules of zinc oxide in a 2 kg sample.
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Answer:
For 12.8 g there 0.807 × 10³ formula units.
Explanation:
Given data:
Mass of MgCl₂ = 12.8 g
Formula units for given mass = ?
Solution:
First of all we will calculate the number of moles.
Number of moles = mass/molar masss
Number of moles = 12.8 g/ 95.211 g/mol
Number of moles = 0.134 mol
According to the Avogadro number,
one moles = 6.022 × 10³ formula units
For 0.134 mol,
0.134 × 6.022 × 10³ formula units
0.807 × 10³ formula units
For 12.8 g there 0.807 × 10³ formula units.
Answer:
78.75g
Explanation:
The density of diamond is the mass of diamond per unit of its volume. The density of a substance is calculated using the formula:
Density (g/cm^3) = mass (g) / volume (cm^3)
According to the question, the density of diamond= 3.15g/cm^3, volume of diamond= 25cm^3, mass = ?
Hence, to calculate the mass, we say;
Mass = Volume × density
Mass = 25 × 3.15
Mass = 78.75
Therefore, the mass of diamond is 78.75grams.
Cl has 7 valence electrons, it needs 8 to be stable, according to the octet rule, so Cl gains stability by gaining 1 electron to reach 8 electrons