A buffer system usually will need a weak acid, like H2CO3, which is carbonic acid, and a strong base, and the only compound that could figure a fairly strong base among the options given is Na2CO3. NH3 and NaHCO3 are weak bases and HF is a strong acid. Therefore the best answer will be letter A
Answer:
1.56 mol H₂
Explanation:
Mg₃(Si₂O₅)₂(OH)₂
<em>There are 4 Si moles per Mg₃(Si₂O₅)₂(OH)₂ mol</em>. With that in mind we can <u>calculate how many Mg₃(Si₂O₅)₂(OH)₂ moles are there in the sample</u>, using the <em>given number of silicon moles</em>:
- 3.120 mol Si *
= 0.78 mol Mg₃(Si₂O₅)₂(OH)₂
Then we can <u>convert Mg₃(Si₂O₅)₂(OH)₂ moles into hydrogen moles</u>, keeping in mind that <em>there are 2 hydrogen moles per Mg₃(Si₂O₅)₂(OH)₂ mol</em>:
- 0.78 mol Mg₃(Si₂O₅)₂(OH)₂ * 2 = 1.56 mol H₂
Answer: solid
Explanation: Chemical reactions are those which involve rearrangement of atoms.
Chemical changes are accompanied by following changes:
1) Absorption or release of heat
2) Change in color
3) Formation of gas bubbles
4) Formation of a solid product called as precipitate
Example of formation of precipitate or solid in chemical reaction:
<h2>Question no 1:</h2><h2>Answer:</h2>
The correct answer is option A which is Sarah is correct because genetic diversity occurs over a long period of time.
<h3>Explanation:</h3>
- Genetic diversity is a large number of allelic combinations for a trait in specie in a population.
- Genetic diversity is caused due to mutations or random breeding in a specie.
- It is good for the adaptation of specie in an environment, due to diverse in genotypes and phenotype of a trait.
<h2>Question number 2:</h2><h2>Answer:</h2>
The correct answer is option B which is the species will adapt to the changes.
<h3>Explanation:</h3>
- Adaptation to an environment means changing your body in such a way to reduce the harmful affects of changing the environment on the body.
- For example, the long and thick fur of sheeps in a snowy area will protect them from cold.
- If the environment changes, the first thing a specie do is an adaptation to that change in the environment.
<h2>Question 3.</h2><h2>Answer:</h2>
The correct answer is option D which is, "The spines of a cactus protect it from animals".
<h3>Explanation:</h3>
- Adaptation to an environment means changing your body in such a way to reduce the harmful affects of changing the environment on the body.
- For example, the long and thick fur of sheeps in a snowy area will protect them from cold.
- So the plant of cactus was in danger due to animals. So the start growing spines in response to animals.
- Hence the correct answer is option D.
<h2>Question 4.</h2><h2>Answer:</h2>
The correct answer is option B which is, "Marie's plant will lean toward the sun so that it can get the most sunlight".
<h3>Explanation:</h3>
- The plant will lean towards the sun light by the mechanism of phototropism.
- Phototropism is the mechanism of growth of the plant in a specific direction in the response of light.
- There are two types of phototropism.
- One is a positive phototropism in which plant grows towards the light.
- The other is negative phototropism in which plant grows away from the light.
- In this question,the plant will do positive tropism.
<h2>Question no. 5</h2><h2>Answer:</h2>
The correct answer is option B which is, "The dodo bird could not adapt quickly to the challenges of the environment".
<h3>Explanation:</h3>
- Adaptation to an environment means changing your body in such a way to reduce the harmful affects of changing the environment on the body.
- For example, the long and thick fur of sheeps in a snowy area will protect them from cold.
- So the dodo could not adopt to the environment. For the positive adaption of survival, they should be afraid of sailors but the would not afraid of a sailor.
- Due to which they went extinct.
Remaining questions are in attached document.
