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Maksim231197 [3]

3 years ago

14

1. A 50 gram sample of a radioisotope decays to 12.5 grams in 14.4 seconds. What is

2 answers:

stiv31 [10]3 years ago

5 0

Answer:

Half life = 7.2 seconds

Explanation:

$from \: decay \: equation \\ 2.303 log( \frac{n.}{nt} ) = kt \\ 2.303 log( \frac{50}{12.5} ) = k \times 14.4 \\ k = \frac{2.303 log( \frac{50}{12.5} )}{14.4} \\ k = 0.096288 {s}^{ - 1} \\ since \: half \: life = \frac{ ln(2) }{k} \\ half \: life = \frac{ ln(2) }{0.096288} \\ half \: life = 7.2 \: seconds$

sp2606 [1]3 years ago

3 0

14.2 because basically you just divide it by 2 which would be half of it

That will work with all of those problems

So if it’s is a quarter of an isotope you’d divide by 4

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What is the single replacement reaction of Zinc + Lead(iv) Chloride

ExtremeBDS [4]

Answer:

$2Zn+PbCl_4\rightarrow 2ZnCl_2+Pb$

Explanation:

Hello there!

In this case, when referring to single replacement reactions, it is crucial for us to figure out the formula of the starting reactants; thus, we know zinc is Zn and lead (IV) chloride is PbCl₄. In such a way, the reaction proceeds as follows:

$Zn+PbCl_4\rightarrow ZnCl_2+Pb$

Which must be balanced as shown below:

$2Zn+PbCl_4\rightarrow 2ZnCl_2+Pb$

Regards!

4 0

3 years ago

Ascorbic acid (H2C6H6O6; H2Asc for this problem), known as vitamin C, is a diprotic acid (Ka1= 1.0x10–5 and Ka2= 5x10–12) found

Igoryamba

Answer:

The concentrations are :

$[HAsc^-]=0.000702 M$

$[Asc^{2-}]=5.92\times 10^{-8} M$

The pH of the solution is 3.15.

Explanation:

$H_2Asc\rightleftharpoons HAs^-+H^+$ $K_{a1}=1.0\times 10^{-5}$

Initial

c 0 0

Equilibrium

c-x x x

$K_{a1}=\frac{[HAs^-][H^+]}{[H_2Asc]}$

$1.0\times 10^{-5}=\frac{x\times x}{(c-x)}$

$1.0\times 10^{-5}=\frac{x^2}{(0.050-x)}$

Solving for x:

x = 0.000702 M

$[HAsc^-]=0.000702 M$

$HAsc^-\rightleftharpoons As^{2-}+H^+$ $K_{a2}=5\times 10^{-12}$

Initially

x 0 0

At equilibrium ;

(x - y) y y

$K_{a2}=\frac{[As^{2-}][H^+]}{[HAsc^-]}$

$5\times 10^{-12}=\frac{y\times y}{(x-y)}$

$5\times 10^{-12}=\frac{y^2}{(x-y)}$

Putting value of x = 0.000702 M

$5\times 10^{-12}=\frac{y^2}{(0.000702 -y)}$

$y=5.92\times 10^{-8} M$

$[Asc^{2-}]=5.92\times 10^{-8} M$

Total concentration of $[H^+]=x+y=0.000702 M+5.92\times 10^{-8} M=7.0206\times 10^{-4} M$

The pH of the solution :

$pH=-\log[H^+]$

$pH=-\log[7.0206\times 10^{-4} M}=3.15$

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3 years ago

Fittoniya [83]

Answer:1

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S_A_V [24]

Answer:

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3 years ago

Which characteristic of money explains why an old dollar is worth as much as a crisp, new dollar?

raketka [301]

The characteristic is uniformity.

<h3>Uniformity of money</h3>

Money is said to be uniform because irrespective of the nature it exists, the same amount must have the same purchasing power.

For example, a dollar in paper form and a dollar in coin form must be able to buy the same 1 dollar worth of goods.

Thus, a dollar bill, irrespective of its age, has the same purchasing power as a new, crisp dollar bill.

More on uniformity of money can be found here: brainly.com/question/17039370

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2 years ago