If you multiply an objects weight times it height, what value do you compute?
2 answers:
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1. <em>Balancing nuclear equations </em>
Answer:
Explanation:
The main point to remember in balancing nuclear equations is that the <em>sums of the superscripts</em> (the mass numbers) and the <em>subscripts</em> (the nuclear charges) <em>must balance</em>.
Mass numbers: 37 + 0 = 37; balanced.
Charges: 18 + 1 = 17; balanced
B is <em>wrong</em>. Mass numbers not balanced. 6 +2(1) ≠ 4 + 3.
C is <em>wron</em>g. Mass numbers not balanced. 254 + 4 ≠ 258 + 2(1).
D is <em>wron</em>g. Mass numbers not balanced. 14 + 4 ≠ 17 + 2.
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2. <em>Amount remaining </em>
Answer:
D. 5.25 g
Explanation:
The half-life of Th-234 (24 da) is the time it takes for half the Th to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table as follows:
No. of Fraction Amount
<u>half-lives</u> <u>t/(da</u>) <u>remaining</u> <u>remaining/g</u>
1 24 ½ 21.0
2 48 ¼ 10.5
3 72 ⅛ 5.25
4 96 ¹/₁₆ 2.62
We see that 72 da is three half-lives, and the amount of Th-234 remaining is 5.25 g.
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3.<em> Calculating the half-life </em>
Answer:
a. 2.6 min
Explanation:
The fraction of the original mass remaining is 1.0 g/4.0 g ≈ ¼.
We saw from the previous table that it takes two half-lives to decay to ¼ of the original amount.
2 half-lives = 5.2 min Divide both sides by 2
1 half-life = 5.2 min/2 = 2.6 min
Check the attached file for the answer.
Here we have to draw the mechanism of the reduction reaction between benzaldehyde and sodium borodeuteride to form the corresponding alcohol.
The reducing agent sodium borodeuteride can reduce the aldehydes to its corresponding alcohol. The reaction mechanism is shown in the attached image.
The reaction mechanism can be explained as-
The sodium borodeuteride is highly ionic in nature thus it remains as Na⁺ and BD₄⁻ The deuterium atom of BD₄⁻ attack the carbonyl carbon atom and substitute one of its deuterium as shown in the figure.
One molecule of sodium borodeuteride can reduce four molecules of benzaldehyde. The polar solvent like alcohol donates the proton as shown in the mechanism.
The converted alcohol contains the deuterium atom at the -C center. Thus benzaldehyde is converted to deuteroted benzyl alcohol.
