<span>The pressure of nitrogen in atmospheres of a sample that is at 745 mmHg-
n2= .780 atm because
78 (from the 78%)
78/100=0.78.</span>
The metric prefix name for 1/100 is centimeters.
<h3>
Answer:</h3>

<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Chemistry</u>
<u>Stoichiometry</u>
- Using Dimensional Analysis
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
[RxN - Balanced] 2Al₂O₃ → 4Al + 3O₂
[Given] 20 mol Al₂O₃
<u>Step 2: Identify Conversions</u>
[RxN] 2 mol Al₂O₃ → 4 mol Al
<u>Step 3: Stoich</u>
- [DA] Set up:

- [DA] Multiply/Divide [Cancel out units]:

<u>Step 4:Check</u>
<em>Follow sig fig rules and round. We are given 1 sig fig.</em>
Since our final answer already has 1 sig fig, there is no need to round.
Answer: The number of protons and the number of neutrons determine an element's mass number.
Explanation:
Answer:
275g
Explanation:
Depending on the molar mass you are given, you can use that to solve this.
(I'm going based on my science class' molar mass of sulphur being 32.07g/mol)
Starting off, the formula for finding moles is
n=m/M (moles = mass / molar mass)
We can manipulate this equation to solve for mass.
m=Mn
now fill in what we now.
m = 32.07*8.56
mass = 274.5192
Now round for significant digits (if you are needed to do)
mass = 275g