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Archy [21]
2 years ago
7

Iodine-131 has a half-life of 8 days. How long would it take for the number of unstable nuclei in the sample to be reduced from

1,000 to 125?
Chemistry
1 answer:
Svet_ta [14]2 years ago
7 0

Answer:

After one-half life: 16 mg

After 2-half lives: 8 mg

After 3-half lives: 4 mg

After 4-half lives: 2 mg

After 5-half lives: 1 mg

(5 half-lives) x (8 days/half-life) = 40 days  

or doing it the mathematical way:  Let z be the number of days to be found:

1 mg = 32 mg x (1/2)^(z / 8 days)  

1/32 = (1/2)^(z / 8 days)  

log (1/32) = (z / 8 days) x log (1/2)  

z / 8 days = log (1/32) / log (1/2)

z = 8 days x log (1/32) / log (1/2) = 40 days

Explanation:

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goldenfox [79]

Answer:

Na+Cl- + Ag+no3- ---> Na+No3- + Ag+Cl-

A spectator ion is an ion that exists as a reactant and a product in a chemical equation

Explanation:

When a solution of sodium hydroxide, NaOH, is mixed with hydrochloric acid, HCl, the compounds dissociate into the ions Na+, OH-, H+ and Cl-. The hydrogen and hydroxide ions react to form water, but the sodium and chlorine ions stay in solution unchanged.

5 0
3 years ago
23.5 L of h2 is stored at a pressure of 58.7 Kpa what volume would the gas take up at stp
stepan [7]

Answer:-  13.6 L

Solution:- Volume of hydrogen gas at 58.7 Kpa is given as 23.5 L. It asks to calculate the volume of hydrogen gas at STP that is standard temperature and pressure. Since the problem does not talk about the original temperature so we would assume the constant temperature. So, it is Boyle's law.

Standard pressure is 1 atm that is 101.325 Kpa.

Boyle's law equation is:

P_1V_1=P_2V_2

From given information:-

P_1 = 58.7 Kpa

V_1 = 23.5 L

P_2 = 101.325 Kpa

V_2 = ?

Let's plug in the values and solve it for final volume.

58.7Kpa*23.5L=101.325Kpa*V_2

On rearranging the equation for V_2

V_2=\frac{58.7Kpa*23.5L}{101.325Kpa}

V_2 = 13.6 L

So, the volume of hydrogen gas at STP for the given information is 13.6 L.

3 0
2 years ago
what two bodies of water form a key transportation route connecting the interior of Canada to the Atlantic Ocean? and its scienc
hodyreva [135]

Answer:

Lake Ontario and St Lawrence Seaway

Explanation:

The Great Lakes are connected to the Atlantic Ocean through the St. Lawrence Seaway.

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3 years ago
How many electrons does carbon need to gain to obtain a noble gas electron configuration
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Carbon has 4 valence electrons so to gain a noble gas electron configuration, which has 8 valence electrons and is the most electrically stable, carbon needs 4 more electrons.
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2 years ago
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I believe 153.6 is the answer.
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2 years ago
Read 2 more answers
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