Answer:
2 a
element pure form cannot broken down
3 b
Chemical change chemical R×N
(R×N = reaction)
4c homogeneous solution
Yield = Yield (reaction yield): A measure of a chemical reaction's efficiency, as a ratio of moles of product to moles of reactant. Usually expressed as a percentage. % Yield = Moles of product.
Explanation:
From the information given:
- The volume of the graduated cylinder = 50.0 mL
- when a sterling silver pendant is added, the volume increases to = 61.3 mL
∴
The volume of the sterling silver pendant is:
= 61.3 mL - 50.0 mL
= 11.3 mL
Since, 1 mL = 1cm³
Then;
11.3 mL = 11.3 cm³
- the density of the sterling silver = 10.25 g/cm³
Using the relation for Density; i.e.
mass = 10.25 g/cm³× 11.3 cm³
mass of the sterling silver = 115.825 grams
Recall that sterling silver has:
- 92.5% silver and;
- 7.5% copper
∴
The mass of the copper contained in the sterling silver pendant can be calculated as:
= 8.687 grams
Therefore, we can conclude that the mass of the copper contained in the sterling silver pendant is 8.687 grams
Learn more about the relation between Density, Mass, and Volume here:
brainly.com/question/24386693?referrer=searchResults
Answer:
C. ΔG is positive at low temperatures, but negative at high temperatures (and zero at some temperature).
Explanation:
Since we need to give energy in the form of heat to vaporize a liquid, the enthalpy is positive. In a gas, molecules are more separated than in a liquid, therefore the entropy is positive as well.
Considering the Gibbs free energy equation:
ΔG= ΔH - TΔS
+ +
When both the enthalpy and entropy are positive, the reaction proceeds spontaneously (ΔG is negative) at high temperatures. At low temperatures, the reaction is spontaneous in the reverse direction (ΔG is positive).