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3 years ago

Is anyone good at chemistry if so Can someone help me please NO LINKS

Chemistry

1 answer:

Nookie1986 [14]3 years ago

4 0

Answer:

6.25 g

Explanation:

From the question given above, the following data were obtained:

Half-life (t½) = 68.8 years

Time (t) = 344 years

Original amount (N₀) = 200 g

Amount remaining (N) =?

Next, we shall determine the number of half-lives that has elapsed. This can be obtained as follow:

Half-life (t½) = 68.8 years

Time (t) = 344 years

Number of half-lives (n) =

n = t / t½

n = 344 / 68.8

n = 5

Thus, 5 half-lives has elapsed.

Finally, we shall determine the amount of the Uranium-232 that remains. This can be obtained as follow:

Original amount (N₀) = 200 g

Number of half-lives (n) = 5

Amount remaining (N) =?

N = 1/2ⁿ × N₀

N = 1/2⁵ × 200

N = 1/32 × 200

N = 200 / 32

N = 6.25 g

Thus, the amount of Uranium-232 that remains is 6.25 g

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Which step of scientific inquiry involves organizing and interpreting the data?

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b. Analysis. In the analysis step, you organize and interpret your data to see if they support your hypothesis.

a. Experimentation is incorrect because this is the step in which you do experiments to test if your prediction is accurate.

c. Conclusion is incorrect because a conclusion is a decision you make to accept or reject your hypothesis.

d. Hypothesis is incorrect because a hypothesis is a proposed explanation for why something happens.

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3 years ago

Need help with this question.... Next to each Formula, write the number of atoms of each element found in one unit of the compou

Andrew [12]

Answer:

The number of atoms present in one unit of the following compounds is:

a). Potassium Iodide , KI = 2

b).Sodium Sulfide, $Na_{2}S$ = 3

c). Silicon Dioxide , $SiO_{2}$ = 3

d). Carbonic Acid , $H_{2}CO_{3}$ = 6

Explanation:

Atomicity : It is defined as the number of atoms that are present in a given molecule/compound.

Atom : The smallest unit of matter is called atom. For e.g O is atom of oxygen but $O_{2}$ is not an atom , it is molecule of oxygen .

$O_{2}$ molecule has 2 atoms of Oxygen

Similarly Na , K , Fe are atoms but $O_{2}$ , $CO_{2}$ , $N_{2}$ , $H_{2}$ are molecules

a).Potassium Iodide

KI = 1 atom of K + 1 atom of I

Total atoms = 2

b) Sodium Sulfide

$Na_{2}S$ = 2 atoms of Na + 1 atom of S

Total atoms = 3

c) Silicon Dioxide

$SiO_{2}$ = 1 atom of Si + 2 atoms of O

Total atoms = 3

d) Carbonic Acid

$H_{2}CO_{3}$ = 2 atom of H + 1 atom of C + 3 atom of O

= 2+1+3

Total atoms = 6

7 0

3 years ago

mixture of N 2 And H2 Gases weighs 13.22 g and occupies a volume of 24.62 L at 300 K and 1.00 atm.Calculate the mass percent of

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Answer: The mass percent of nitrogen gas and hydrogen gas is 91.41 % and 8.59 % respectively.

Explanation:

To calculate the number of moles, we use the equation given by ideal gas equation:

PV = nRT

where,

P = Pressure of the gaseous mixture = 1.00 atm

V = Volume of the gaseous mixture = 24.62 L

n = number of moles of the gaseous mixture = ?

R = Gas constant = $0.0821\text{ L atm }mol^{-1}K^{-1}$

T = Temperature of the gaseous mixture = 300 K

Putting values in above equation, we get:

$1.00atm\times 24.62L=n_{mix}\times 0.0821\text{ L atm }mol^{-1}K^{-1}\times 300K\\\\n_{mix}=\frac{1.00\times 24.62}{0.0821\times 300}=0.9996mol$

We are given:

Total mass of the mixture = 13.22 grams

Let the mass of nitrogen gas be 'x' grams and that of hydrogen gas be '(13.22 - x)' grams

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

For nitrogen gas:

Molar mass of nitrogen gas = 28 g/mol

$\text{Moles of nitrogen gas}=\frac{x}{28}mol$

For hydrogen gas:

Molar mass of hydrogen gas = 2 g/mol

$\text{Moles of hydrogen gas}=\frac{(13.22-x)}{2}mol$

Equating the moles of the individual gases to the moles of mixture:

$0.9996=\frac{x}{28}+\frac{(13.22-x)}{2}\\\\x=12.084g$

To calculate the mass percentage of substance in mixture we use the equation:

$\text{Mass percent of substance}=\frac{\text{Mass of substance}}{\text{Mass of mixture}}\times 100$

Mass of the mixture = 13.22 g

For nitrogen gas:

Mass of nitrogen gas = x = 12.084 g

Putting values in above equation, we get:

$\text{Mass percent of nitrogen gas}=\frac{12.084g}{13.22g}\times 100=91.41\%$

For hydrogen gas:

Mass of hydrogen gas = (13.22 - x) = (13.22 - 12.084) g = 1.136 g

Putting values in above equation, we get:

$\text{Mass percent of hydrogen gas}=\frac{1.136g}{13.22g}\times 100=8.59\%$

Hence, the mass percent of nitrogen gas and hydrogen gas is 91.41 % and 8.59 % respectively.

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3 years ago

In Perugino's Christ Delivering the Keys of the Kingdom to St. Peter, the artist reminds the viewer of the link between Constant

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Answer:

Is an exemplar of Italian Renaissance painting.

Explanation:

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3 years ago

The intake stroke of a positive displacement compressor is most similar to that of a

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Answer:

D. two-stroke cylinder engine.

Explanation:

Two-stroke cylinder engine: In chemistry, the term "two-stroke cylinder engine" is described as one of the types of "internal combustion engine" that tends to complete a single "power cycle" possessing two different strokes of the "piston" during a particular "crankshaft revolution".

It generally consists of two different strokes that are being often known as power or exhaust and suction stroke.

In the question above, the given statement signifies the "two-stroke cylinder engine". 

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3 years ago