Answer:
2.03 moles of Gold
Explanation:
Gold is one of the most precious metal metal used in many applications and mainly as a jewellery. In terms of purity it is categorized in Karats. 24 Karat is considered the purest Gold (i.e. 100 % Gold) while other Karats (14, 18, 22 e.t.c) are alloys with other metals and gyms.
Data Given:
Mass of Gold = 400 g
A.Mass of Gold = 196.97 g.mol⁻¹
Calculate Moles of Gold as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 400 g ÷ 196.97 g.mol⁻¹
Moles = 2.03 moles of Gold
Answer:
The particles of the liquid slide around faster as the kinetic energy of the particles increases.
Explanation:
After all the bonds in the solid state are broken in part CD, the more free particles in the liquid state gain more kinetic energy with increase in energy supplied.
The increase in kinetic energy is indicated by the temperature increase thus the positive gradient of the part CD.
Kinetic energy means more vibrations thus the particles slide more and more against each other.
Answer:
pH = 12.5
Explanation:
The reaction that takes place is
- 2OH⁻(aq) + Pb⁺²(aq) → Pb(OH)₂(s)
The OH⁻ species come from the metal hydroxide of the solution, and Pb(OH)₂ is the precipitate.
Now we <u>convert 3.81 grams of Pb(OH)₂ into moles</u>, using its <em>molar mass</em>:
- 3.81 g ÷ 241.12 g/mol = 0.0158 mol Pb(OH)₂
Now we <u>convert 0.0158 Pb(OH)₂ moles into OH⁻ moles</u>, using the <em>stoichiometric coefficients of the reaction</em>:
- 0.0158 mol Pb(OH)₂ *
= 0.0316 mol OH⁻
With the given concentration (1 L), we <u>calculate [OH⁻]</u>:
- [OH⁻] = 0.0316 mol / 1 L = 0.0316 M
Then we <u>calculate the pOH</u> of the solution:
And finally we <u>calculate the pH</u>:
