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3 years ago

You are given 230 grams of a substance with a half-life of 0.75 years. How much will remain after 3 years?

Chemistry

1 answer:

Degger [83]3 years ago

6 0

After 3 years, the substance will go through 4 half lives. You can do 230*(1/2)^4, which is 14.375.

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Can someone who expert in chemistry be my personal tutor? I'm so desperate

lions [1.4K]

Yes..? I don’t understand what you’re trying to ask mate.

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3 years ago

Water has a high specific heat because: Select one: a. it is a poor insulator b. hydrogen bonds must be broken to raise its temp

Crank

<h2>The required "option is b) hydrogen bonds must be broken to raise its temperature.</h2>

Explanation:

Water has high specific heat due to hydrogen bonds present in it.
The Ionisation of water does not affect the specific heat of the water.
On decreasing the temperature, there is the formation of bonds hence option (d) is wrong.
On increasing the temperature, there is the breaking of bonds hence option (b) is correct.

3 0

3 years ago

How many atoms are present in 65.39 g of zinc?

klio [65]

<span>Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles.

65.39 g Zn ( 1 mol / 65.38 g ) ( </span>6.022 x 10^23 atoms / 1 mol ) = 6.023x10^23 atoms Zn

3 0

3 years ago

One of the reactions that occurs in a blast furnace, in which iron ore is converted to cast iron, is Fe2O3 + 3CO → 2Fe + 3CO2 Su

Tpy6a [65]

Answer : The percent purity of $Fe_2O_3$ in the original sample is 87.94 %

Explanation :

The given balanced chemical reaction is:

$Fe_2O3+3CO\rightarrow 2Fe+3CO_2$

First we have to calculate the mass of Fe.

$\text{Moles of }Fe=\frac{\text{Mass of }Fe}{\text{Molar mass of }Fe}$

Molar mass of Fe = 55.8 g/mole

$\text{Moles of }Fe=\frac{1.79\times 10^3kg}{55.8g/mole}=\frac{1.79\times 10^3\times 1000g}{55.8g/mole}=3.15\times 10^4mole$

Now we have to calculate the moles of $Fe_2O_3$

From the balanced chemical reaction we conclude that,

As, 2 moles of Fe produced from 1 mole of $Fe_2O_3$

So, $3.15\times 10^4mole$ of Fe produced from $\frac{3.15\times 10^4}{2}=15750$ mole of $Fe_2O_3$

Now we have to calculate the mass of $Fe_2O_3$

$\text{ Mass of }Fe_2O_3=\text{ Moles of }Fe_2O_3\times \text{ Molar mass of }Fe_2O_3$

Molar mass of $Fe_2O_3$ = 159.69 g/mole

$\text{ Mass of }Fe_2O_3=(15750moles)\times (159.69g/mole)=2.515\times 10^6g=2.515\times 10^3kg$

Now we have to calculate the percent purity of $Fe_2O_3$ in the original sample.

Mass of original sample = $2.86\times 10^3kg$

$\text{Percent purity}=\frac{\text{Mass of }Fe_2O_3}{\text{Mass of sample}}\times 100$

$\text{Percent purity}=\frac{2.515\times 10^3kg}{2.86\times 10^3kg}\times 100=87.94\%$

Therefore, the percent purity of $Fe_2O_3$ in the original sample is 87.94 %

3 0

3 years ago

What is the redox equation for sulphuric acid and magnesium ribbon

Wewaii [24]

Sulfuric acid: $H_2SO_4_{(aq)}$
Magnesium ribbon: $Mg_(s)$
$Mg_{(s)}+H_2SO_4_{(aq)} \rightarrow MgSO_4_{(aq)}+H_2_{(g)}$

8 0

3 years ago