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2 years ago

Base your answers to questions 74 through 76 on the data table below and on your knowledge of Earth

Chemistry

1 answer:

Serjik [45]2 years ago

6 0

Answer:

See explanation

Explanation:

Now we have, the graph attached.the stable disintegration product of C-14 is N-14.

Then;

Since the mass of C-14 originally present is 64g, at a time t= 17100 years, we will have;

N/No = (1/2)^t/t1/2

N = mass of C-14 at time t

No= mass C-14 originally present

t = time taken for N amount of C-14 to remain

No = mass of C-14 originally present

t1/2 = half life of C-14

N/64 = (1/2)^17,100/5730

N/64 = (1/2)^3

N/64 = 1/8

8N = 64

N = 8 g

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Stainless steel is an alloy of iron containing 5 percent nickel and 0.175 percent chromium. How many atoms of nickel are present

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First you need to work out what mass of 84g of stainless steel is nickel, and because there's 5% you can simply divide by 20, giving 4.2g

For this you can use the equation $Moles= \frac{Mass}{Mr}$

The mass, as was worked out previously, is 4.2g
The Mr, which is found on the periodic table, is 28

Moles = $\frac{4.2}{28}$ = 0.15mol

1mol = 6.023 x $10^{23}$ atoms

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How many atoms of oxygen (o)are present 2naOH+H2SO4 2H2O+Na2SO4

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Answer:

Explanation:

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3 years ago

How many grams of copper (II) hydroxide can be prepared from 2.4 grams of copper (II) nitrate (Cu(NO3)2 ) and excess sodium hydr

andreyandreev [35.5K]

Answer:

percentage yield = 67%

Explanation:

Mass of Cu(NO₃)₂ = 15.25 g

Mass of NaOH = 12.75 g

Percentage yield = ?

Solution:

Cu(NO₃)₂ + 2NaOH → Cu(OH)₂ + 2NaNO₃

Moles of Cu(NO₃)₂:

Number of moles = mass/ molar mass

Number of moles = 15.25 g /187.56 g/mol

Number of moles = 0.08 mol

Moles of NaOH :

Number of moles = mass/ molar mass

Number of moles = 12.75 g / 40 g/mol

Number of moles = 0.32 mol

Now we will compare the moles of Cu(OH)₂ with NaOH and Cu(NO₃)₂. NaOH : Cu(OH)₂

2 : 1

0.32 : 1/2×0.32 = 0.16 mol

Cu(NO₃)₂ : Cu(OH)₂

1 : 1

0.08 : 0.08

The number of moles produced by Cu(NO₃)₂ are less so it will limiting reactant.

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Mass = number of moles × molar mass

Mass = 0.08 mol × 97.6 g/mol

Mass = 7.808 g

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percentage yield = Actual yield/ theoretical yield × 100

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2 years ago

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Ivenika [448]

Answer:

D: Carbon

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Carbon is also by itself, just C.

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Air is just a mixture of different gas molecules, so therefore it is not an element.

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likoan [24]

Answer:

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