Which trends are observed when the elements in Period 3 on the Periodic Table are considered in order of increasing atomic number?(1) The atomic radius decreases, and the first ionization energy generally increases.
(2) The atomic radius decreases, and the first ionization energy generally decreases.
(3) The atomic radius increases, and the first ionization energy generally increases.
(4) The atomic radius increases, and the first ionization energy generally decreases.

Answer:

B. Catalyst B

Explanation:

Explanation: Enzymes are complex proteins that have a very specific shape. Just as a key fits a lock and allows it to open, the active site of the enzyme fits the reactants, allowing them to meet at the right orientation to form new chemical bonds. The shape of catalyst B is the best fit to the given reactants and product. The presence of catalysts allows reactions to proceed at much lower energy levels than without, as high-energy collisions between molecules are no longer necessary.

Answer;

The above statement is false

Explanation;

Photosynthesis is the biological conversion of light or electromagnetic energy from the Sun into chemical energy. It occurs in green plants, algae, and some types of bacteria, and requires a series of biochemical reactions.

In photosynthesis, carbon dioxide and water react with one another in the presence of light and a chemical known as chlorophyll to produce a simple carbohydrate and oxygen.

Fossils of what are thought to be filamentous photosynthetic organisms have been dated at 3.4 billion years old. Geological evidence suggests that oxygenic photosynthesis, such as that in cyanobacteria, became important during the Paleoproterozoic era around 2 billion years ago.

I put true into the answer and it was wrong so it is actually FALSE.

The answer above is incorrect.

If 20 g of hydrogen is reacted with 32 g of oxygen to produce 9 g of water, the percentage yield is 5%.

What is Percent yield?

Percent yield is the ratio of the actual yield times the theoretical yield to 100. When the actual and theoretical yield are equal, the percentage yield is 100%. So if the actual yield is less than the theoretical yield then the percentage yield is less than 100%. This situation may arise due to the incompleteness of the reaction or the loss of the sample during the recovery process.

According to the stoichiometry of reaction of formation of water,

4 g hydrogen gives 36 g water, thus, 20 g hydrogen gives 20×36/4=180 g water which is theoretical yield.

So, the percent yield=observed yield/theoretical yield×100

percent yield=9/180×100=5%.

Thus, if 20 g of hydrogen is reacted with 32 g of oxygen to produce 9 g of water, the percentage yield is 5%.

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Answer:

12.5%

Explanation:

32/16 = 2 moles of oxygen

2 x 18.01 x 2/1 = 72.04 g of H2O

9/72.04 x 100 = 12.5%

balanced equation: 2H2 + O2 → 2H2O

limiting reactant is oxygen