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3 years ago

100 POINTS PLEASE HELP

Chemistry

1 answer:

Gennadij [26K]3 years ago

6 0

Answer:

1. 39.997 g/mol

2. 6.022⋅1023 atoms of aluminium

3. 0.026 moles

4. 14 grams is the molar mass of nitrogen meaning that one mole of nitrogen atoms is 14 grams. One mole of any substance has 6.02*10^23 atoms/molecules of that subtance therefore there are 6.02*10^23 atoms of nitrogen in 14g of nitrogen

5. 78.5

Explanation:

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A gas sealed in a drum container occupies 7.70 L at a sizzling 325C degrees. What will the volume be if the drum is quickly chi

grigory [225]

The volume of the drum after chilled quickly is 3.6 L.

<u>Explanation:</u>

As per the Charles Law, for any gas at constant pressure, volume of the gas is in direct proportion with the temperature measured in Kelvin. As the temperature increases, the gas expands and vice versa.

$$\frac{V1}{T1} = \frac{V2}{T2} \\$

After chilling the drum, the volume will get reduced and it can be found as,

V2 = $$\frac{V1T2}{T1}$

= $$\frac{7.7 L \times 282 K}{598 K}$

= 3.6 L

Here the drum is chilled quickly, that is temperature is reduced and so the volume also decreases.

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3 years ago

Why does every chemical reaction require a certain amount of activation energy

attashe74 [19]

Every chemical reaction requires a minimum amount of energy to undergo reaction.

The total energy required is Threshold energy. The chemicals have some internal energy and they require some extra energy which is known as activation energy.

The reaction occurs when two molecules or atoms come closer to each other and for this they need kinetic energy.

Now for an effective collision the two molecules or atoms should collide with a minimum amount of energy so that they may undergo reaction so again they need some energy

These kinetic energy and energy for effective collision is actually called as activation energy.

5 0

3 years ago

. Citric acid, which can be obtained from lemon juice, has the molecular formula C6H8O7. A 0.250-g sample of citric acid dissolv

marysya [2.9K]

Answer:

3 acidic hydrogens per molecule of citric acid

Explanation:

In a sample of 37.2 mL(0.0372 L) of 0.105 mol/L of NaOH, will have:

n = 0.105x0.0372 = 0.0039 mol of NaOH

The dissociation of NaOH will give the same number of moles of Na⁺ and OH⁻.

The molar mass of citric acid is:

C: 12g/mol x 6 = 72 g/mol

H: 1g/mol x 8 = 8g/mol

O: 16 g/mol x 7 = 112 g/mol

192 g/mol

So, 0.250g of the acid has

n = mass/molar mass

n = 0.250/192

n = 0.0013 mol.

To be neutralized, it will be necessary 0.0039 mol of acidic hydrogens to react with the 0.0039 mol of OH⁻.

The dissociation reaction of one molecule of the acid will give the stoichiometry:

1 mol of acid ----------------------- x mol of acidic hydrogens

0.0013 mol --------------------------- 0.0039

For a simple direct three rule:

0.0013x = 0.0039

x = 3 acidic hydrogens per molecule of citric acid.

3 0

4 years ago

Dioxane, C4H8O2, has an enthalpy of fusion of 145.8 J g–1 and its melting point temperature is 11.0 °C. How much heat is require

kumpel [21]

Answer:

20703.6J

Explanation:

Quantity of heat (Q) = mass of dioxane × enthalpy of fusion

Mass of dioxane = 142g

Enthalpy of fusion of dioxane = 145.8J/g

Q = 142g × 145.8J/g = 20703.6J

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4 years ago

Select all of the following which are examples of physical change.

Vladimir79 [104]

Change of appearance, change in size and shape of a substance, change in phase of a substance, and I'm pretty sure expansion/contraction is an answer, too.

3 0

3 years ago