Mass of K = 39.1g/mole
Mass of H = 1g/mole
Mass of C = 12g/mole
Mass of O = 16g/mole
Mass of KHCO3 = 39.1 + 1 + 12 + 3*16 = 100,1g/mole
100% ------------ 100.1g of KHCO3
x% ----------------- 12g of C
x = 11,99% of C in KHCO3
100% -------------- 100.1 of KHCO3
y% --------------------3*16g of O
y = 47,95% of O in KHCO3
100% ------------- 100.1g of KHCO3
z% ---------------- 1g of H
z = 0,99% of H in KHCO3
11,99% + 47,95% + 0,99% = 60,93% ≈ 61%
<u>answer: C</u>
Conservation
conservation is the act of protecting animals and resources for current and future generations
Answer:
Heptane (d) > Hexane (b) 3,3 dimethyl pentane (c) > butane (a)
Explanation:
<u>The boiling points of the alkanes are depends on the following factors:</u>
- Hydrocarbons with strong intermolecular forces have high boiling points.
- Longer carbon chain molecules have high boiling points.
- Straight chain hydrocarbon molecules have high boiling points than the branched chain hydrocarbons molecules because straight chain molecule have large surface area.
The given molecules are as follows.
a) Butane
b) Hexane
c) 3,3 dimethyl pentane
d) Heptane.
The Highest to lowest boiling point order is as follows.
Heptane (d) > Hexane (b) 3,3 dimethyl pentane (c) > butane (a)
The answer to the question is D.
Answer:
D. 44.2 g O₂
General Formulas and Concepts:
<u>Gas Laws</u>
- STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at <em>1 atm, 273 K</em>
<u>Stoichiometry</u>
- Dimensional Analysis
- Mole Ratio
Explanation:
<u>Step 1: Define</u>
<em>Identify given.</em>
61.9 L O₂ at STP
<u>Step 2: Convert</u>
We know that the oxygen gas is at STP. Therefore, we can set up and solve for how many <em>moles</em> of O₂ is present:
Recall the Periodic Table (Refer to attachments). Oxygen's atomic mass is roughly 16.00 grams per mole (g/mol). We can use a mole ratio to convert from <em>moles</em> to <em>grams</em>:
Now we deal with sig figs. From the original problem, we are given 3 significant figures. Round your answer to the <u>exact</u> same number of sig figs:
∴ our answer is letter choice D.
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Topic: AP Chemistry
Unit: Stoichiometry