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pantera1 [17]
3 years ago
7

What is the yearly exposure from wearing a watch with a luminous dial?

Chemistry
1 answer:
Marizza181 [45]3 years ago
3 0
Until well in the 60ties, the luminous dials of wrist watches and alarm clocks were marked with luminous paints containing Radium (Ra-226) or Promethium (Pm-147). These kind of watches are no longer manufactured today. This is not due to the radiation exposure to the persons wearing the watches but because of the radiological risk for the persons manufacturing them.

Hope this helps
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Which one of the following reactions would produce t-butyl methyl ether in high yield?
swat32

Answer:

D) sodium t-butoxide + bromomethane

Explanation:

The alkoxide ion is a strong nucleophile, that unlike alcohols, will react with primary alkyl halides to form ether. This general reaction is known as <em>the Williamson synthesis</em>, and is a SN₂ displacement. The alkyl halide must be primary so the back side attack is not hindered, and the alkoxide ion must be formed with the most hindered group.

The mechanism can be seen in the attachment.

7 0
3 years ago
Identify the conjugate acid/base pairs in each of the following equations:
Valentin [98]

Answer:

(a) Pair 1: H₂S and HS⁻

    Pair 2: NH₃ and NH₄⁺

(b) Pair 1: HSO₄⁻ and SO₄⁻

    Pair 2: NH₃ and NH₄⁺

(c) Pair 1: HBr and Br⁻

    Pair 2: CH₃O⁻ and CH₃OH

(d)  Pair 1: HNO₃ and NO₃⁻

     Pair 2: H₃O⁺

Explanation:

When an acid loses its proton (H⁺), a conjugate base is produced.

When a base accepts a proton (H⁺), it forms a conjugate acid.

(a) H₂S is an acid. When it loses a proton, it forms the conjugate base HS⁻.

    NH₃ is a base. When NH₃ gains a proton, it forms the conjugate acid NH₄⁺

(b) The acid HSO₄⁻ loses a H⁺ ion and forms the conjugate base SO₄²⁻.

     The base NH₃ accepts a H⁺ ion to form the conjugate acid NH₄⁺.

(c) HBr is an acid. When loses the H⁺ ion, it forms the conjugate base Br⁻.

   CH₃O⁻ accepts a H⁺ ion to form the conjugate acid CH₃OH.

(d) HNO₃ loses a proton to form the conjugate base NO₃⁻.

    H₂O gains a proton to form the conjugate acid H₃O⁺.

6 0
3 years ago
Please help!
Alchen [17]
After crossbreeding, the seeds will be in the form below
Rr, Rr, rr and rr
which is two for each in four possible outcomes bringing the ratio to 1:1
which is equivalent to 1/2
so 1/2 as a percentage is
=1/2*100
=50%
8 0
3 years ago
Read 2 more answers
A 0.100 m solution of butanoic acid has a % deprotonation of 1.23%. determine the ph of the butanoic acid solution.
MrRissso [65]
Chemical reaction: C₃H₇COOH → C₃H₇COO⁻ + H⁺.
c(<span>butanoic acid) = 0,100 M.
</span>α = 1,23% = 0,0123.
Ka = α² · c / 1 - α.
Ka = 0,0123² · 0,1 M / 1 - 0,0123.
Ka = 0,0000153 M.
Ka = c(C₃H₇COO⁻) · c(H⁺) / c(C₃H₇COOH).
c(H⁺) = α · c(C₃H₇COOH).
c(H⁺) = 0,0123 · 0,1 M = 0,00123 mol/L.
pH = -log c(H⁺).
pH = 2,91.

4 0
3 years ago
PLEASE HELP ME IM CONFUSED
lisov135 [29]

Given -

T = 450K

∆H = 3000J

∆S = 4J/K

Using formula

∆G = ∆H - T∆S

∆G = 3000- 4*450

∆G = 1200 Joule

∆G is positive so the reaction is non spontaneous!

6 0
3 years ago
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