4. Given the balanced equation: 2Na + S → Na₂S How many grams of sulfur are needed to react with 43 grams of Na? Round to the nearest whole number.

a. 119 g
b. 158 g
c. 32 g
d. 30 g

Option D. 30 g

Explanation:

The balanced equation for the reaction is given below:

2Na + S —> Na₂S

Next, we shall determine the masses of Na and S that reacted from the balanced equation. This is can be obtained as:

Molar mass of Na = 23 g/mol

Mass of Na from the balanced equation = 2 × 23 = 46 g

Molar mass of S = 32 g/mol

Mass of S from the balanced equation = 1 × 32 = 32 g

SUMMARY:

From the balanced equation above,

46 g of Na reacted with 32 g of S.

Finally, we shall determine the mass sulphur, S needed to react with 43 g of sodium, Na. This can be obtained as follow:

From the balanced equation above,

46 g of Na reacted with 32 g of S.

Therefore, 43 g of Na will react with = (43 × 32)/46 = 30 g of S.

Thus, 30 g of S is needed for the reaction.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.