The molecular mass of sodium = 23g
One mole of sodium consists of 23 g of sodium
One mole consists of 1 Avagadro(6.022 x 10^23 molecules) number of molecules
Therefore 23 g consists of 6.022 x 10^23 molecules of Sodium.
Hence 7.45 x 10^3 g of Sodium will consist of x no of molecules of sodium.
x no of molecules =
(7.45 x 10^3 g/23 g) x (6.022 x 10^23)
=1950.6 x 10^ 23 molecules (atoms).
Answer: 1.41725 X 10^{24} atoms
Explanation:
One male of any gas containing no. of atoms
2.5 moles of gas containing no. of atoms
The given gas is triatomic gas. Hence
No. of atoms

Answer: 
Explanation: A double displacement reaction is one in which exchange of ions take place.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

Based on the information provided, it appears that you will need to calculate the amount of heat absorbed by the water from the peanut that was burned. We are given the following information:
specific heat capacity, c = 1.0 cal/g°C
mass of water = 76 g
Ti = 22°C
Tf = 46°C
change in temperature, ΔT = 24°C
We can use the formula q = mcΔT to measure the amount of energy absorbed by the water to increase in tempature:
q = (76 g)(1.0 cal/g°C)(24°C)
q = 1824 cal
Therefore, the water absorbed 1824 calories from the peanut that was burned.
To convert from moles to grams you divide by the molar mass of the element. To convert from grams to moles you X by the molar mass element