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musickatia [10]
3 years ago
9

Hurry PLEASE HELP!

Chemistry
1 answer:
avanturin [10]3 years ago
7 0

B. 11,540

<h3>Further explanation </h3>

The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.  

Usually radioactive elements have an unstable atomic nucleus.  

General formulas used in decay:  

\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

Nt=25 g

No=100 g

t1/2=5770 years

\tt 25=100\dfrac{1}{2}^{T/5770}\\\\\dfrac{1}{4}=\dfrac{1}{2}^{T/5770}\\\\2=T/5770\rightarrowT=11540~years

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Answer:

15.4%

Explanation:

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C₄H₈O₂               -------->            C₄H₇O₂⁻          +           H⁺

I                    0.54x10⁻³                             0                                0

E                   0.54x10⁻³(1-x)                      0.54x10⁻³x                0.54x10⁻³x

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From the ICE table;

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1.51x10⁻⁵=(0.54x10⁻³x) (0.54x10⁻³x)/ 0.54x10⁻³(1-x)  

1.51x10⁻⁵ = 0.54x10⁻³x^2/1-x

1.51x10⁻⁵(1-x) = 0.54x10⁻³x^2

1.51x10⁻⁵ - 1.51x10⁻⁵x = 0.54x10⁻³x^2

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0.54x10⁻³x^2 + 1.51x10⁻⁵x - 1.51x10⁻⁵=0

x^2 + 0.028x - 0.028 = 0

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Answer:

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Given that;

the wt% of copolymer consist of 12.9 wt% of vinyl acetate and 87.1 wt% Ethylene.

Basis: 100 g of PEVA consist of 12.9 of vinyl acetate and 87.1g of Ethylene.

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the molecular weights of vinyl acetate and ethylene are 86.09 g/mol and 28.05 g/mol respectively

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moles of vinyl acetate = wt. of vinyl acetate / molecular weights of vinyl acetate

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Total moles = 0.1498 mol + 3.1052 mol = 3.255 mol

Next we calculate the mole percent;

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X_{V} = (0.1498 mol / 3.255 mol) × 100

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mole percent of Ethylene X_{E} = moles of Ethylene / total  moles

X_{E}  = (3.1052 mol / 3.255 mol) × 100

X_{E}  = 95.397% ≈ 95.4%

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DP_{n} = \frac{M_{n} }{M}

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so we substitute

DP_{n} = 39,870 g/mol / 30.72 g/mol

DP_{n}  = 1297.85 ≈ 1300   { 3 significance figure }

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