Answer:
25 grams
Explanation:
You strat off with 400 grams of your substance. By day 14, half has dcayed and you only have 200 grams left. By day 28, there are 100 grams of the substance. On day 42, there are 50 grams left. Finally, on day 56, the substance has been through four half-lives and 25 grams remain.
Answer:
2.13 x 10³moles
Explanation:
Given parameters:
Number of molecules in AlF₃ = 1.28 x 10²⁷molecules
Unknown:
Number of moles = ?
Solution:
A mole is a quantitative unit in chemistry used of taking measurements.
A mole of a substance is the amount of that substance that contains the avogadro's number of particles.
The particles can be molecules, atoms, neutrons, protons, electrons or formula units.
Number of moles =
Number of moles = = 2.13 x 10³moles
Answer:
0.75 mol
Explanation:
Given data:
Number of moles of Na = 0.75 mol
Mass of water = 500 g
Moles of hydrogen gas produced = ?
Solution:
Chemical equation:
Na + H₂O → NaO + H₂
Number of moles of water:
Number of moles = mass/molar mass
Number of moles = 500 g/ 18 g/mol
Number of moles = 27.8 mol
now we will compare the moles of hydrogen gas with both reactant.
Na : H₂
1 : 1
0.75 : 0.75
H₂O : H₂
1 : 1
27.8 : 27.8
sodium will act as limiting reactant it produced small number of moles of hydrogen gas as compared to water.
Thus, number of moles of hydrogen gas are 0.75 mol.
<h3>
Answer:</h3>
251 mol Xe
<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>Atomic Structure</u>
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<u>Stoichiometry</u>
- Using Dimensional Analysis
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
[Given] 1.51 × 10²⁶ atoms Xe
[Solve] moles Xe
<u>Step 2: Identify Conversions</u>
Avogadro's Number
<u>Step 3: Convert</u>
- [DA] Set up:
- [DA] Multiply/Divide [Cancel out units]:
<u>Step 4: Check</u>
<em>Follow sig fig rule and round. We are given 3 sig figs.</em>
250.747 mol Xe ≈ 251 mol Xe