The answer is going to be d
Answer:

General Formulas and Concepts:
<u>Chemistry - Gas Laws</u>
- STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K
- Charles' Law:

Explanation:
<u>Step 1: Define</u>
Initial Volume: 5.0 L H₂ gas
Initial Temp: 273 K
Final Temp: 985 K
Final Volume: ?
<u>Step 2: Solve for new volume</u>
- Substitute:

- Cross-multiply:

- Multiply:

- Isolate <em>x</em>:

- Rewrite:

<u>Step 3: Check</u>
<em>We are given 2 sig figs as the smallest. Follow sig fig rules and round.</em>
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Fishes yes according to the age, reptiles yes
Answer:
3.43 %
Explanation:
We need to calculate first the number of moles of CeO2 produced in the combustion. Given its formula we know how many moles of Ce atom are present. From there calculate the mass this number of moles this represent and then one can calculate the percentage.
0.1848 g CeO2 x 1 mol CeO2/172.114g = 0.00107 mol CeO2
0.00107 mol CeO2 x 1 mol Ce/ 1 mol CeO2 = 0.00107 mol Ce
.00107 mol Ce x 140.116 g Ce/ mol = 0.150 g Ce
0.150 g Ce/ 4.3718 g sample x 100 = 3.43 %
Answer:
A. the atomic number
Explanation:
It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth.