Answer:
The first one.
Explanation:
When comparing two fractions with variables like this, it's important to get to the same denominator in order to compare apples with apples and then be able to do not only comparisons but also perform additions/subtractions.
Question is which denominator to use and how to reach it.
In this case, the question and the answer choices do the work for you. The question asks which one is the LEAST common denominator, and the answers show denominators x² and 4x². The smallest of these is x², however, we can't simplify the first fraction to get to the x² denominator, so we'll go for the 4x².
So, the first fraction has already the correct denominator (4x²), we just have to transform the second one.
We multiply it by 1, expressed in a different way. Since we're multiplying by one, we're not affecting the value, just the way it looks.
Let's do it!, to get the denominator to go from x² to 4x², we need to multiply it by 4... so we'll multiply by 4/4 (which is 1, neutral for the multiplication).
And now you have both fractions on the same denominator, without having changed their value, just their looks
Answer:
336.6 grams of CO₂ and 183.6 grams of H₂O are formed from 2.55 moles of propane.
Explanation:
In this case, the balanced reaction is:
C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O
By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of reactant and product participate in the reaction:
- C₃H₈: 1 mole
- O₂: 5 moles
- CO₂: 3 moles
- H₂O: 4 moles
Being the molar mass of each compound:
- C₃H₈: 44 g/mole
- O₂: 16 g/mole
- CO₂: 44 g/mole
- H₂O: 18 g/mole
Then, by stoichiometry, the following quantities of mass participate in the reaction:
- C₃H₈: 1 mole* 44 g/mole= 44 grams
- O₂: 5 moles* 16 g/mole= 80 grams
- CO₂: 3 moles* 44 g/mole= 132 grams
- H₂O: 4 moles* 18 g/mole= 72 grams
So you can apply the following rules of three:
- If by stoichiometry 1 mole of C₃H₈ forms 132 grams of CO₂, 2.55 moles of C₃H₈ how much mass of CO₂ will it form?
mass of CO₂= 336.6 grams
- If by stoichiometry 1 mole of C₃H₈ forms 72 grams of H₂O, 2.55 moles of C₃H₈ how much mass of H₂O will it form?
mass of H₂O= 183.6 grams
<u><em>336.6 grams of CO₂ and 183.6 grams of H₂O are formed from 2.55 moles of propane.</em></u>
Answer:
<em> 1</em>. A. 0
<em>2</em>. B. 7
<em>3. </em>C<em>.</em><em> </em>4
Explanation:
1. charge is equal to the number of protons minus the number of electrons!
2. neutrons is equal to mass number minus atomic number!
3. valence electrons equal 4!
Hope this helped you! :)
Why don’t you have friends?
Answer:
C. 63.3%
Explanation:
Theoretical yield = 47.2g
Actual yield = 29.9g
Percentage yield = ?
The percentage yield of a compound after chemical synthesis is the ratio of the actual yield to the theoretical yield multiplied by 100.
Percentage yield = (actual yield / theoretical yield) × 100
Percentage yield = (29.9 / 47.2) × 100
Percentage yield = 0.6334 × 100
Percentage yield = 63.34%
The percentage yield of Fe is 63.34%
