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2 years ago

When 0.639 L of a 0.60 M solution is diluted to 2.822 L, what is the new molarity? Report your answer with 4 decimal places.

Chemistry

1 answer:

Liono4ka [1.6K]2 years ago

7 0

Answer:

The new molarity is 0,1359M.

Explanation:

A dilution consists of the decrease of concentration of a substance in a solution (the higher the volume of the solvent, the lower the concentration).

We use the formula for dilutions:

C1 x V1 = C2 x V2

0,60 M x 0,639 L= C2 x 2,822 L

C2=(0,60 M x 0,639 L)/ 2, 822 L

C2=0,1359 M

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Temka [501]

Answer : The enthalpy of the reaction = -1839.6 KJ

Solution : Given,

$\Delta (H_{f})_{MnO_{2}}$ = -520.0 KJ/mole

$\Delta (H_{f})_{Al_{2}O_{3}}$ = -1699.8 KJ/mole

The balanced chemical reaction is,

$3MnO_{2}(s)+4Al(s)\rightarrow 2Al_{2}O_{3}(s)+3Mn(s)$

Formula used :

$\Delta (H_{f})_{reaction}=\sum n(\Delta H_{f})_{product}-\sum n(\Delta H_{f})_{reactant}$

$\Delta (H_{f})_{reaction}=(2\times \Delta H_{Al_{2}O_{3}(s)}+3\times \Delta H_{Mn(s)} )-(3\times \Delta H_{MnO_{2}(s) }+4\times\Delta H_{Al}(s))$

We know that the standard enthalpy of formation of the element is equal to Zero.

Therefore, the enthalpy of formation of (Mn) and (Al) is equal to zero.

Now, put all the values in above formula, we get

$\Delta (H_{f})_{reaction}=[2moles\times (-1699.8 KJ/mole)}+3moles\times (0\text{ KJ/mole}})]-[(3moles\times(-520.0KJ/mole }+4moles\times(0\text{ KJ/mole})]$

= (-3399.6) + (1560)

= -1839.6 KJ

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3 years ago

A compound is 75.46% Carbon, 4.43% hydrogen and 20.10% Oxygen by mass. it has a molecular weight of 318.31g/mol. what is the mol

DiKsa [7]

Answer:

No.of moles of C is , n = mass/molar mass = 75.46 g / 12 (g/mol) = 6.3 moles No.of moles of H is , n' = mass/molar mass = 4.43 g / 1.0(g/mol) = 4.43 moles No.of moles of O is , n'' = mass/molar mass = 20.10 g / 16(g/mol) =1.25 moles Ratio to the no.of moles of C,H& O is 6.3 : 4.43 : 1.25 In the simple integer ratio is ( 6.3/1.25) : ( 4.43/1.25) : (1.25/1.25) 5.04 :3.5 : 1

Explanation:

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2 years ago

"calculate the ratio of the velocity of hydrogen molecules to the velocity of carbon dioxide molecules at the same temperature"

Ne4ueva [31]

Answer: 1:4.69

Explanation:

The ratio can be expressed as:

Ua/Ub= √(Mb/Ma)

Where Ua/Ub is the ratio of velocity of hydrogen to carbon dioxide and Ma is the molecular mass of hydrogen gas= 2

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Therefore

Ua/Ub= √(44/2)

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Therefore the ratio of velocity of hydrogen gas to carbon dioxide = 1:4.69

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3 years ago

A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next fe

Inga [223]

Answer:

The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.

Explanation:

As molecules heat they begin to move faster. The heat from the metal plate will make the molecules at room temperature move faster. And the room temperature makes the hot place cool, making the hot plate molecules slow down.

To visualize this, you can use this link

https://phet.colorado.edu/en/simulations/gas-properties

click the play button to activate the activity

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1 year ago

What is the volume of 0.80 grams of O2 gas at STP? (5 points) Group of answer choices 0.59 liters 0.56 liters 0.50 liters 0.47 l

Anarel [89]

Answer:

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Explanation:

First we convert 0.80 grams of O₂ into moles, using its molar mass:

0.80 g ÷ 32 g/mol = 0.025 mol

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Thus the answer is 0.56 liters.

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2 years ago