Answer:
Al
Explanation:
The reduction potentials of the metals are
Al= -1.66
Zn= -0.76
Cu= +0.34
Pb= -0.13
Hence All has the most negative reduction potential and is the most reducing element among all the elements listed.
Answer:
C: Plants mostly need air, water and sunlight to grow
Explanation:
Denitrifying Bacteria such as Pseudomonas aeruginosa is the type of bacteria that use enzyme nitrate reductase to metabolise nitrogen oxides to nitrogen gas.
Denitrification is the process whereby nitrites or nitrogen oxides is converted to nitrogen gas by a denitrifying Bacteria such as Pseudomonas.
Pseudomonas aeruginosa uses enzyme nitrate reductase to reduce nitrate to nitrite.
Then nitrite is then converted back to nitrogen gas.
Therefore, Pseudomonas aeruginosa is a type of bacteria that uses enzyme nitrate reductase.
Answer:
0.0468 g.
Explanation:
- The decay of radioactive elements obeys first-order kinetics.
- For a first-order reaction: k = ln2/(t1/2) = 0.693/(t1/2).
Where, k is the rate constant of the reaction.
t1/2 is the half-life time of the reaction (t1/2 = 1620 years).
∴ k = ln2/(t1/2) = 0.693/(1620 years) = 4.28 x 10⁻⁴ year⁻¹.
- For first-order reaction: <em>kt = lna/(a-x).</em>
where, k is the rate constant of the reaction (k = 4.28 x 10⁻⁴ year⁻¹).
t is the time of the reaction (t = t1/2 x 8 = 1620 years x 8 = 12960 year).
a is the initial concentration (a = 12.0 g).
(a-x) is the remaining concentration.
∴ kt = lna/(a-x)
(4.28 x 10⁻⁴ year⁻¹)(12960 year) = ln(12)/(a-x).
5.54688 = ln(12)/(a-x).
Taking e for the both sides:
256.34 = (12)/(a-x).
<em>∴ (a-x) = 12/256.34 = 0.0468 g.</em>
