Answer: D: a volcano forming a new island in a chain
Explanation:
Answer:
(102 900 ÷ 12) + (170 × 1.27) = 8800
Step 1. Evaluate the expressions inside the parentheses (PEMDAS)
102 900 ÷ 12 = 8575
170 × 1.27 = 215.9
In multiplication and division problems, your answer can have no more significant figures than the number with the fewest significant figures.
Thus, the underlined digits are not significant, but we keep them in our calculator to avoid roundoff error.
Step 2. Do the addition (PEMDAS).
8575
+ 215.9
= 8790.9
Everything that you add to an insignificant digit gives an insignificant digit as an answer.
Thus, the underlined digits are not significant.
We must drop them and round up the answer to 8800.
Explanation:
Answer:
Nitric acid decomposes sodium cyanide and sodium halide. else, they precipitate in test and misguide the result. Therefore, dilute nitric acid is added before testing halogens to expel all the gases if evolved.
Answer:
Hydride ion
Explanation:
You often see the reduction with NADH written as
NADH ⟶ NAD⁺ + H⁺ + 2e⁻
If you think about it, H⁺ + 2e⁻ is equivalent to H:⁻, so we could write the reaction as
NADH ⟶ NAD⁺ + H:⁻
In terms of a mechanism, the dihydropyridine ring of NADH transfers a hydrogen atom with its pair of electrons (a hydride ion) to the substrate and becomes the more stable, aromatic pyridinium ion in NAD⁺.
