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3 years ago

Phosphorus-32 has a half life of 14.3 days. How many days will it take for a

Chemistry

1 answer:

olya-2409 [2.1K]3 years ago

3 0

It will take 42.9 days

<h3>Further explanation</h3>

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

t1/2=14.3 days

Nt/No=1/8

$\tt Nt=No(\dfrac{1}{2})^{T/t1/2}\\\\\dfrac{Nt}{No}=\dfrac{1}{2}^{T/t1/2}\\\\\dfrac{1}{8}=\dfrac{1}{2}^{T/t1/2}\\\\(\dfrac{1}{2})^3=\dfrac{1}{2}^{T/t1/2}\\\\3=T/14.3\rightarrow T=42.9~days$

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pychu [463]

Answer:

16.79 grams of dinitrogen monoxide are present after 31.3 g of calcium nitrate and 38.7 g of ammonium fluoride react completely. And calcium nitrate is a limiting reactant. Explanation:

$Ca(NO_3)_2(aq)+2NH_4F(aq)\rightarrow CaF_2(aq)+2N_2O(g)+4H_2O(g)$

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According to reaction , 2 moles of ammonium fluoride reacts with 1 mole of calcium nitrate.

Then 1.046 moles of ammonium fluoride will react with :

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This means that ammonium fluoride is in excess amount and calcium nitrate is in limiting amount.

Hence, calcium nitrate is a limiting reactant.

So, amount of dinitrogen monoxide will depend upon moles of calcium nitrate.

So, according to reaction , 1 mole of calcium nitarte gives 2 moles of dinitrogen monoxide gas .

Then 0.1908 moles of calcium nitrate will give:

$\frac{2}{1}\times 0.1908 mol=0.3816 mol$ of dinitrogen monoxide gas.

Mass of 0.03816 moles of dinitrogen monoxide gas:

0.03816 mol × 44 g/mol = 16.79 g

16.79 grams of dinitrogen monoxide are present after 31.3 g of calcium nitrate and 38.7 g of ammonium fluoride react completely. And calcium nitrate is a limiting reactant.

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3 years ago

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Answer: Three things are missing:

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iii) The scale and the units for the horizontal axis.

Justification:

1) Find the graph in the image attached.

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Since you are told in the statement that it is a temperature and volume graph, the appropiate title would be:

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A good label for the vertical axis of this graph might be: Volume (cm³). It migh also be liters, gallons, or other volume unit.

4) Although the horizontal axis is labeled, it does not indicate the units and the scale. So, you know neither if the temperature shown is celsius, (°C), farenheti (°F), kelvin (K), or rankine (R) (those are the four major scales of temperature), nor how much each division represent (1, 5, 10, 10, 50, 100?)

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Answer:

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