Part 1. You are testing a family heirloom necklace (without permission of course, but it’s for science!). The 18-karat gold piece is 77% gold by mass, 15% silver, and 8.0% copper.
a. Determine the mass, in grams, of the necklace if you find 0.26 oz of silver.
b. How many grams of copper are in the necklace?
c. If 18-karat gold in this necklace has a density of 17.2 g/cm3, what is the volume in cubic centimeters?

Part 2. The curb weight of a Tesla Model S electric car is 4,647.3 lbs. The mass of an average kumquat is 0.7 oz. Find the number of Teslas that would be required to have the same mass as 1.0 mol of kumquats.

Part 3. Write a balanced chemical equation for each reaction.
a. Gaseous ammonia reacts with gaseous oxygen to form gaseous nitrogen monoxide and gaseous water.
b. Solid copper reacts with solid sulfur to form solid copper(I) sulfide.
c. Solid iron(III) oxide reacts with hydrogen gas to form solid iron and liquid water.
d. Liquid pentane reacts with gaseous oxygen to form carbon dioxide and liquid water.

Part 4. Based on the given starting conditions, determine the limiting reactant, theoretical yield and the percent yield of the following balanced reactions. Show all calculations. Your answers should be in the same units you are provided (e.g. if you are given grams, theoretical yield should be in grams). Ca+Cl2→ CaCl2
63.21 g Ca and 72.46 g Cl2 yield 103.45 g CaCl2
Limiting Reagent:___________
Theoretical Yield:___________
Percent Yield:___________
CuNO3(𝑎𝑞)+NaOH(𝑠)→ CuOH(𝑠)+NaNO3(𝑎𝑞)
50.21 mL of 0.102 M CuNO3 and 0.250 g NaOH yield 0.401 g CuOH
Limiting Reagent:___________
Theoretical Yield:___________
Percent Yield:___________

Part 5. A balloon filled with 1.63 g of helium (Cs=5.19 J/g∙K) is compressed from 10.60 liters to 9.13 liters at 1.00 atm while the temperature drops from 26.0 °C to 21.5 °C. What is the total change in internal energy (ΔE)?
Part 6. Determine the change in enthalpy of each reaction using the information provided.
P4O6+2 O2→ P4O10 ΔH = ?
P4+3 O2→ P4O6 ΔH = -1640.1 kJ
P4+5 O2→ P4O10 ΔH = -2940.1 kJ
Part 7. A leaf has a surface area of 690 mm2. If solar radiation is 1000 W/m2, how many
photons strike the leaf every second? Assume an average wavelength of 504 nm for solar radiation.

Part 8. Consider these elements: N, Mg, C, O, Al
a. Write the electron configuration for each element.
b. Arrange the elements in order of decreasing atomic radius.
c. Arrange the elements in order of decreasing ionization energy.

Part 9. Write the Lewis structure for each molecule:
a. NF3
b. HBr
c. SBr2
d. CCl4
e. C4H4

Part 1. You are testing a family heirloom necklace (without permiss...