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2 years ago

How much heat (in kilojoules) is evolved or absorbed in the reaction of 1.90g of Na with H2O ?

1 answer:

6 0

The heat of the reaction is an extensive property: it is proportional to the quantity of the quantity that reacts.

The change in enthalpy is a measured of the heat evolved of absorbed.

When the heat is released, the change in enthalpy is negative.

The reaction of 2 moles of Na develops 368.4 kj of energy.

Calculate the number of moles of Na in 1.90 g to find the heat released when this quantity reacts.

Atomic mass of Na: 23 g/mol

#mol Na = 1.90 g / 23 g/mol = 0.0826 mol

Do the ratios: [368.4 kj/2mol ] * 0.0826 mol = 15.21 kj.

Then the answer is that 15.21 kj of heat is released (evolved)

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Question 2 (2 points)

inysia [295]

Answer:

v = 46.5 m/s

Explanation:

Given data:

Mass of car = 1210 kg

Momentum of car = 56250 kg m/s

Velocity of car = ?

Solution:

Formula:

p = mv

p = momentum

m = mass

v = velocity

Now we will put values in formula:

56250 kg m/s = 1210 kg × v

v = 56250 kg m/s / 1210 kg

v = 46.5 m/s

So a car having mass of 1210 kg with momentum 56250 kg m/s having 46.5 m/s velocity.

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3 years ago

What type of fuel is burned in a nuclear power plant?

Hatshy [7]

Answer:

greenhouse gases

7 0

2 years ago

Help me

Valentin [98]

Answer:

South American

Explanation:

When you look at a map of plates, only South American forms a boundary with the African plate out of those specific plates

6 0

2 years ago

Read 2 more answers

An unknown amount of acid can often be determined by adding an excess of base and then back-titrating the excess. A 0.3471−g sam

MAXImum [283]

Explanation:

The given data is as follows.

Mass of mixture = 0.3471 g

As the mixture contains oxalic acid and benzoic acid. So, oxalic acid will have two protons and benzoic acid has one proton.

This means oxalic acid will react with 2 moles of NaOH and benzoic acid will react with 1 mole of NaOH.

Hence, moles of NaOH in 97 ml = $\frac{0.1090 \times 97}{1000}$

= $10.573 \times 10^{-3} mol$

Moles of HCl in 21.00 ml = $\frac{0.2060 \times 21}{1000}$

= $4.326 \times 10^{-3}$ mol

Therefore, total moles of NaOH that reacted are as follows.

$10.573 \times 10^{-3} mol$ - $4.326 \times 10^{-3} mol$

= $6.247 \times 10^{-3}$ mol

So, total 3 mole of NaOH will react with 1 mole of mixture. Therefore, number of moles of NaOH reacted with benzoic acid is as follows.

$\frac{6.247 \times 10^{-3}}{3}$

= $2.082 \times 10^{-3}$ mol

Since, molar mass of NaOH is 40 g/mol. Therefore, calculate the mass of NaOH as follows.

$2.082 \times 10^{-3} mol \times 40 g/mol$

= $83.293 \times 10^{-3}$ g

= 0.0832 g

Whereas molar mass of benzoic acid is 122 g/mol.

Therefore, 40 g NaOH = 122 g benzoic acid

So, 0.0832 g NaOH = $\frac{122 g}{40 g} \times 0.0832 g$

= 0.253 g

Hence, calculate the % mass of benzoic acid as follows.

$\frac{0.253 g}{0.3471 g} \times 100$

= 73.10%

Thus, we can conclude that mass % of benzoic acid is 73.10%.

4 0

3 years ago

Something that is made out of natural resources for human use is called

ANEK [815]

Answer:

Man-made resources

Explanation:

Humanized resources are items or substances that have value to human lives that do not occur in the natural world. Examples of man-made resources include plastic, paper, soda, sheet metal, rubber and brass. These contrast with natural resources, such as water, crops, sunlight, crude oil, wood and gold.

6 0

2 years ago