All problems are caused by a factor in which human beings play an important role in its cause.
Question:
Layer 1 and 2 → Animal fossil
Layer 3 and 4 → First plant fossil
Layer 5 → Animal fossil
Layer 6→ Second plant fossil
Layer 7 → Animal fossil.
Answer:
The correct option to choose answer is;
C) Layers 3 and 4 (Secondary succession layer).
Explanation:
Secondary succession is a concept related to pliant life and it describes the notion of an ecosystem regenerates after being destroyed and it takes place when the level of disruption is not enough to do away with all present vegetation and present soil from a location.
Secondary succession is started by an incident that destroys to a large extent the present ecosystem. Events that start secondary succession includes;
1) Hurricane
2) Fire and
3) Harvesting.
Answer:
Theoretical yield: 2.75g of paranitroaniline
Percentage yield: 54.5%
Explanation:
In strong-acid medium, acetanilide (Molar mass: 135.16g/mol) reacts producing para-nitroaniline (138.12g/mol) in a 1/1 reaction.
Theoretical yield of para-nitroaniline is the mass produced assuming a yield of 100%. That is:
2.7g acetanilide × (1mol / 135.16g) = 0.020 moles of acetanilide.
Assuming a yield of 100% are 0.020 moles of paranitroaniline. Theoretical yield is:
0.020 moles × (138.12g / mol) =
<h3>Theoretical yield: 2.75g of paranitroaniline</h3><h3 />
Percentage yield is:
(Actual yield / theoretical yield) × 100
Actual yield was 1.5g and percentage yield will be:
Percentage yield: (1.5g / 2.75g) × 100
<h3>Percentage yield: 54.5%</h3>
The balanced equation for the above reaction is as follows;
Na₂SO₄ + BaCl₂ --> BaSO₄ + 2NaCl
Na₂SO₄ reacts with BaCl₂ in the molar ratio 1:1
Number of Na₂SO₄ moles - 10.0 g / 142.1 g/mol = 0.0704 mol
Number of BaCl₂ moles - 10.0 g / 208.2 g/mol = 0.0480 mol
this means that 0.0480 mol of each reactant is used up, BaCl₂ is the limiting reactant and Na₂SO₄ has been provided in excess.
stoichiometry of BaCl₂ to BaSO₄ is 1:1
number of BaSO₄ moles formed - 0.0480 mol
Mass of BaSO₄ - 0.0480 mol x 233.2 g/mol = 11.2 g
theoretical yield is 11.2 g but the actual yield is 12.0 g
the actual product maybe more than the theoretical yield of the product as the measured mass of the actual yield might contain impurities.
percent yield - 12.0 g/ 11.2 g x 100% = 107%
this is due to impurities present in the product or product could be wet.
