Answer : 6.41 moles of silicon are in the sample.
Solution : Given,
Moles of magnesium = 9.62 moles
The given chemical formula for talc is, 
From the given chemical formula we conclude that
The stoichiometry of magnesium and silicon is 3 : 2
3 moles of magnesium is equivalent to 2 moles of silicon
9.62 moles of magnesium will be equivalent to 
moles of silicon
Therefore, the number of silicon present in sample are 6.41 moles.
Rate = k[A] = first order reaction
<h3>Further explanation</h3>
Given
Rate law
Required
A first-order reaction
Solution
The rate law : equation for the rate of chemical reaction
For reaction
aA + bB ⇒ C
The rate : r = k[A]ᵃ[B]ᵇ
The sum of exponents(a+b) is the reaction order
From the choice :
a. a+b = 2, second order reaction
b. a+b = 3, third order reaction
c. a+b = 4, fourth order reaction
d a+0 = 1, first order reaction
Materials that are good conductors of thermal energy are called thermal conductors. Metals are especially good thermal conductors because they have freely moving electrons that can transfer thermal energy quickly and easily
2.86 atm of pressure is more than 2000 mm of Hg
2.86 atm of pressure = 2173.6 mm of Hg
