Answer:

Explanation:
Since we are given the mass, specific heat, and change in temperature, we should use this formula for heat:

The substance's mass is 450.0 grams, the specific heat is 1.264 J/g°C, and the change in temperature is 7.1 °C.

Substitute the values into the formula.

Multiply the first 2 values together. The grams will cancel out.

Multiply again. This time, the degrees Celsius cancel out.

<u>4038.48 Joules</u> of heat energy are released.
Explanation:
Pressure of a gas is the combined force with which the molecules bombard a unit area of the wall of the container.
1 atm = 760mmHg
= 760torr
= 101325Pa
= 101325Nm⁻²
1mmHg = 1torr
1Pa = 1Nm⁻²
101.325 kPa and 101,325 Pa are the same
1000Pa = 1kPa
101,325 Pa and 1 atm
1atm and 101.325 kPa
Half reaction 1: 2Fe° → Fe₂³⁺ + 6e⁻ /×2.
4Fe° → 2Fe₂³⁺ + 12e⁻.
Iron is oxidized from neutral charge (0) to oxidation number +3, one iron lose three electrons, two irons lose six electrons and four irons twelve electrons.
Half reaction 2: 12e⁻ + 3O₂ → 2O₃²⁻
Oxygen is reduced from neutral chage to oxidation number -2, one oxygen gain two electrons, six oxygens gain twelve electrons.
Balanced chemical reaction: 4Fe + 3O₂ → 2Fe₂O₃.
Answer:
B)
an atom of mercury has a different mass than an atom of copper.
Explanation: