Explanation:
When an electromagnetic wave like light hits a material, the electrons gets emitted. The emission of electrons is called photoelectric effect. The emitted electrons are called photoelectrons. In this process the transfer of energy takes place from light to an electron.
Hence, the correct option regarding the photoelectric experiment is (A) " Light can cause electrons to be released from the surface of a metal."
To balance any redox equation, first divide the reaction into two half reactions, and balance the atom whose oxidation number is changing:
<span>NO2 --> NH3 </span>
<span>H2 --> H2O </span>
<span>Next, balance oxygens by adding H2O where needed, and then balance hydrogen by adding H+: </span>
<span>NO2 --> NH3 + 2 H2O </span>
<span>H2O + H2 --> H2O </span>
<span>7 H+ + NO2 --> NH3 + 2 H2O </span>
<span>H2O + H2 --> H2O + 2 H+ </span>
<span>Next, balance charges by adding electrons (e-): </span>
<span>7 H+ + NO2 + 7 e- --> NH3 + 2 H2O </span>
<span>H2O + H2 --> H2O + 2 H+ + 2 e- </span>
<span>Now, multiply one or both equations by small numbers to make the number of electrons the same in the two half reactions. In this case, multiply the top equation by 2 and the bottom one by 7 to give you 14 electrons in each half reaction: </span>
<span>14 H+ + 2 NO2 + 14 e- --> 2 NH3 + 4 H2O </span>
<span>7 H2O + 7 H2 --> 7 H2O + 14 H+ + 14 e- </span>
<span>Finally, add the two half reactions and simplify by cancelling anything that is on both sides. This will give you the final balanced reaction: </span>
<span>2 NO2 + 7 H2 --> 2 NH3 + 4 H2O </span>
<span>So, the answer to the original question is (A) 7
</span>
Answer:
C. Synthesis reaction
Explanation:
Because the water is being made (synthesized) from two <u>elements</u> it is a synthesis reaction.
Answer:
d) They're studying something for which they cant do an experiment
Explanation:
