PLEASE HELP

3 g of H₂

Explanation:

The balanced equation for the reaction is given below:

Cr₂O₃ + 3H₂ —> 2Cr + 3H₂O

Next, we shall determine the masses of Cr₂O₃ and H₂ that reacted from the balanced equation. This can be obtained as follow:

Molar mass of Cr₂O₃ = (52×2) + (16×3)

= 104 + 48

= 152 g/mol

Mass of Cr₂O₃ from the balanced equation = 1 × 152 = 152 g

Molar mass of H₂ = 2 × 1 = 2 g/mol

Mass of H₂ from the balanced equation = 3 × 2 = 6 g

SUMMARY:

From the balanced equation above,

152 g of Cr₂O₃ reacted with 6 g of H₂

Finally, we shall determine the mass of H₂ needed to covert 76 g of Cr₂O₃. This can be obtained as follow:

From the balanced equation above,

152 g of Cr₂O₃ reacted with 6 g of H₂.

Therefore, 76 g of Cr₂O₃ will react with = (76 × 6) / 152 = 3 g of H₂

Thus, 3 g of H₂ is needed to convert 76 g of Cr₂O₃.

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates