D.
The prefix “exo” indicates a release. “-thermic” indicates heat. Because there is a release of heat, the reaction gives off heat and is warm to the touch. Î”H is negative because there is a loss of heat energy.

3 0

3 years ago

The number of grams of H2 in 1470 mL of H2 gas.

Lorico [155]

Answer:

0.1313 g.

Explanation:

It is known that at STP, 1.0 mole of ideal gas occupies 22.4 L.

Suppose that hydrogen behaves ideally and at STP conditions.

Using cross multiplication:

1.0 mol of hydrogen occupies → 22.4 L.

??? mol of hydrogen occupies → 1.47 L.

∴ The no. of moles of hydrogen that occupies 1.47 L = (1.0 mol)(1.47 L)/(22.4 L) = 6.563 x 10⁻² mol.

Now, we can get the no. of grams of hydrogen in 6.563 x 10⁻² mol:

The no. of grams of hydrogen = no. of hydrogen moles x molar mass of hydrogen = (6.563 x 10⁻² mol)(2.0 g/mol) = 0.1313 g.

5 0

3 years ago