and D. to identify minerals
The change in energy of the system : -63 J
<h3>Further explanation</h3>
Given
279 J work
216 J heat
Required
The change in energy
Solution
Laws of thermodynamics 1
ΔU=Q+W
Rules :
- receives heat, Q +
- releases heat, Q -
- work is done by a system, W -
- work is done on a system, W +
a gas work on the surrounding : W =-279 J
a gas absorb heat from surrounding : Q = +216 J
Internal energy :
= -279+216
= -63 J
Answer:
1.37 × 10²³ Atoms of Mercury
Solution:
Step 1: Calculate Mass of Mercury using following formula,
Density = Mass ÷ Volume
Solving for Mass,
Mass = Density × Volume
Putting values,
Mass = 13.55 g.cm⁻³ × 3.4 cm³ ∴ 1 cm³ = 1 cc
Mass = 46.07 g
Step 2: Calculating number of Moles using following formula;
Moles = Mass ÷ M.mass
Putting values,
Moles = 46.07 g ÷ 200.59 g.mol⁻¹
Moles = 0.229 mol
Step 3: Calculating Number of Atoms using following formula;
Number of atoms = Moles × 6.022 ×10²³
Putting value of moles,
Number of Atoms = 0.229 mol × 6.022 × 10²³
Number of Atoms = 1.37 × 10²³ Atoms of Hg
