The early precambrian atmosphere consisted primarily of nitrogen and carbon dioxide with almost no oxygen.
<span>Today, the atmosphere contains about 20% oxygen, less carbon dioxide and similar amounts of nitrogen. </span>
<span>Photosynthetic green-leaf plants and trees are largely responsible for the change, converting carbon dioxide to oxygen.</span>
Answer: Lexington and Concord
Explanation: The British were trying to find weapons and could not find them.
If the grade of the ore is 37.3% nickel, then the unknown quantity to get 10 grams of nickel is 0.373 x = 10 grams or x = 10/0.373=26.8 grams or 0.0268 kg needed to dig up to recover the 10 grams of nickel. At this grade of ore, 1 kilogram would yield 373 grams of nickel.
Answer:
The answer is wind energy.
Explanation:
I did the quiz on time4learning.
Half reaction :
Oxidation
Cu ⇒ Cu²⁺ + 2e⁻
Reduction
2Ag⁺+ 2e⁻ ⇒2Ag
<h3>Further explanation</h3>
Given
Reaction
Cu+2AgNO₃⇒Cu(NO₃)₂+2Ag
Required
Oxidation and reduction half-reactions
Solution
Oxidation is an increase in oxidation number, while reduction is a decrease in oxidation number.
Cu ⇒ Cu²⁺ + 2e⁻
0 to +2
2Ag⁺+ 2e⁻ ⇒2Ag
+1 to 0