A sample of tungsten II sulfate contains 4.17 times 10 exponent 24 molecules what is the mass of this sample ??

1937.6g

Explanation:

According to the question, a sample of tungsten II sulphate (WSO4) contains 4.17 × 10^24 molecules. This means that the number of moles can be calculated by dividing the number of molecules by Avagadro's number (6.02 × 10^23).

Number of moles of WSO4 = 4.17 × 10^24 ÷ 6.02 × 10^23

n = 4.17/6.02 × 10^(24-23)

n = 0.692 × 10^1

n = 6.92moles

Where; W = 184g/mol, S = 32g/mol, O = 16g/mol

The molar mass of tungsten II sulphate (WSO4) is calculated as follows;

WSO4 = 184 + 32 + 16(4)

= 184 + 32 + 64

= 280g/mol

mole = mass ÷ molar mass

mass = molar mass (MM) × number of moles (n)

mass = 280 × 6.92

mass = 1937.6g

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.