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3 years ago

Chem timed exam, help plz

Chemistry

1 answer:

Alchen [17]3 years ago

5 0

Answer:

3.864 g of C₃H₆

Explanation:

The balanced equation for the reaction is given below:

2C₃H₆ + 9O₂ —> 6CO₂ + 6H₂O

From the balanced equation above,

2 moles of C₃H₆ reacted to produce 6 moles of CO₂

Next, we shall determine the number of mole of C₃H₆ that reacted to produce 0.276 mole of CO₂. This can be obtained as follow:

From the balanced equation above,

2 moles of C₃H₆ reacted to produce 6 moles of CO₂.

Therefore, Xmol of C₃H₆ will react to produce 0.276 moles of CO₂ i.e

Xmol of C₃H₆ = (2 × 0.276)/6

Xmol of C₃H₆ = 0.092 mole

Finally, we shall determine the mass of 0.092 mole of C₃H₆. This can be obtained as follow:

Mole of C₃H₆ = 0.092 mole

Molar mass of C₃H₆ = (12×3) + (6×1)

= 36 + 6

= 42 g/mol

Mass of C₃H₆ =?

Mass = mole × molar mass

Mass of C₃H₆ = 0.092 × 42

Mass of C₃H₆ = 3.864 g

Therefore, 3.864 g of C₃H₆ is needed for the reaction.

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How many grams of sulfuric acid is needed to neutralize 380 ml of solution with pH = 8.94

erma4kov [3.2K]

Answer : The mass of sulfuric acid needed is $16.23\times 10^{-5}g$ .

Solution : Given,

pH = 8.94

Volume of solution = 380 ml = $380\times 10^{-3}$ $(1ml=10^{-3}L)$

Molar mass of sulfuric acid = 98.079 g/mole

As we know,

$pH+pOH=14\\pOH=14-8.94=5.06$

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$5.06=-log[OH^-]$

$[OH^-]=0.00000871=8.71\times 10^{-6}mole/L$

Now we have to calculate the moles of $OH^-$ .

Formula used : $Moles=Concentration\times Volume$

$\text{ Moles of }[OH^-]=\text{ Concentration of }[OH^-]\times Volume\\\text{ Moles of }[OH^-]=(8.71\times 10^{-6}mole/L)\times (380\times 10^{-3}L)=3309.8\times 10^{-9}moles$

For neutralization, equal number of moles of $H^+$ ions will neutralize same number of $OH^-$ ions.

$\text{ Moles of }[OH^-]=\text{ Moles of }[H^+]=3309.8\times 10^{-9}moles$

As, $H_2SO_4\rightarrow 2H^++SO^{2-}_4$

From this reaction, we conclude that

2 moles of $H^+$ ion is given by the 1 mole of $H_2SO_4$

$3309.8\times 10^{-9}$ moles of $H^+$ ion is given by $\frac{3309.8\times 10^{-9}}{2}=1654.9\times 10^{-9}$ moles of $H_2SO_4$

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Mass of sulfuric acid = Moles of $H_2SO_4$ × Molar mass of sulfuric acid

Mass of sulfuric acid = $(1654.9\times 10^{-9}moles)\times (98.079g/mole)=162310.94\times 10^{-9}=16.23\times 10^{-5}g$

Therefore, the mass of sulfuric acid needed is $16.23\times 10^{-5}g$ .

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3 years ago

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Answer:

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3 years ago

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DerKrebs [107]

Answer:

a. Interference patterns are observed when a wave passes through a barrier with two slits

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the diagram attached below shows the movement of a wave through a barrier with two slits.

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Thus, option A is correct.

The other options however, are not correct. as shown below:

Option B is wrong as waves exhibit diffraction <em>(it is diffraction of the light wave that produces the rainbows we see in the sky)</em>

Option C is wrong as waves do not travel straight through slits always.

Option D is wrong as waves can also interfere constructively and destructively.

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Answer:

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3 years ago

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