Answer:
Periods have consecutive atomic number as they are in a row and groups are vertical meaning they are in a column and groups have similar properties
<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.
The time taken by Carbon-14 to decay radioactively from 120g to 112.5g is 22,920 years.
<h3>How do we calculate the total time of decay?</h3>
Time required for the whole radioactive decay of any substance will be calculated by using the below link:
T = (n)(t), where
- t = half life time = 5730 years
- n = number of half life required for the decay
Initial mass of Carbon-14 = 120g
Final mass of Carbon-14 = 112.5g
Left mass = 120 - 112 = 7.5g
Number of required half life for this will be:
- 1: 120 → 60
- 2: 60 → 30
- 3: 30 → 15
- 4: 15 → 7.5
4 half lives are required, now on putting values we get
T = (4)(5730) = 22,920 years
Hence required time for the decay is 22,920 years.
To know more about radioactive decay, visit the below link:
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It respresents the higher energy level than 627nm .
<h3>What is a emission line ? </h3>
Emission lines are the glowing hot gas emits lines of light whereas absorption line refers to the tendency of cool atmospheric gas to absorb the same line of light.Some lights produce dark band when the light passes through gas in the atmosphere . There are two line spectrum and absorption.
spectrum is an excitement of electrons from lower to higher energy levels and when it comes back it releases energy in the terms of colourful lights .
It represents the higher energy levels than 627nm because Energy is inversly proportional to wavelength .
to learn more about Emission lines click here
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Number of moles ( substance x ):
1 mole --------- 58.45 g/mol
? mole --------- 326.0 g
326.0 x 1 / 58.45 => 5.577 moles
heat of fusion:
hf = Cal / moles
hf = 4325.8 Cal / 5.577 moles
hf = 775.65 cal/mol
hope this helps!
