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3 years ago

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Chemistry

1 answer:

nasty-shy [4]3 years ago

6 0

Answer: The different amount of lights in his classroom

Explanation:it would be the lights because the dependent ariable would be how sleepy his students who get or be

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0.53g of acetanilide was subjected to kjeldahl determination and the ammonia produced was collected in 50cm3 of 0.50M of h2so4.o

Lady bird [3.3K]

Answer:

10.57% of N in acetanilide

Explanation:

All nitrogen in the sample is converted in NH₃ in the Kjeldahl determination. The NH₃ reacts with H₂SO₄ as follows:

2NH₃ + H₂SO₄ → 2NH₄⁺ + SO₄²⁻

The acid in excess in titrated with Na₂CO₃ as follows:

Na₂CO₃ + H₂SO₄ → Na₂SO₄ + H₂O + CO₂

To solve this question we must find the moles of sodium carbonate = Moles of H₂SO₄ in excess. The added moles - Moles in excess = Moles of sulfuric acid that reacts:

Moles Na₂CO₃ anf Moles H₂SO₄ in excess:

0.025L * (0.05mol / L) = 1.25x10⁻³ moles Na₂CO₃ / 0.01360L =

0.09191M * 0.250L = 0.0230 moles H₂SO₄ in excess.

Moles H₂SO₄ added:

0.050L * (0.50mol / L) = 0.0250 moles H₂SO₄ added

Moles that react:

0.0250 moles - 0.0230 moles = 0.0020 moles H₂SO₄

Moles of NH₃ = Moles N:

0.0020 moles H₂SO₄ * (2mol NH₃ / 1mol H₂SO₄) = 0.0040 moles NH₃ = Moles N

mass N and mass percent:

0.0040 moles N * (14g / mol) = 0.056gN / 0.53g * 100 =

<h3>10.57% of N in acetanilide</h3>

7 0

2 years ago

Josie see's lightning off in the distance. A few seconds later she hears thunder. What can Josie conclude?

ycow [4]

The answer is b) light waves travel faster than sound waves.

4 0

3 years ago

Which of these force is reponsible for attracting the opposite poles of two bar magments towards each other

TEA [102]

The magnetic fields are the reason why magnets repel and attract. eachother.

7 0

3 years ago

Read 2 more answers

Benzene can be nitrated with a mixture of nitric and sulfuric acids. How do we do that?

Montano1993 [528]

Answer:

We can do the nitration of benzene by treating the benzene with a mixture of nitric acid and sulphuric acid by not extending the temperature of 50°C

Explanation:

Nitration of benzene takes place by treating the benzene with a mixture of nitric acid and sulphuric acid at low temperatures such as the temperatures below 50°C

The nitration of benzene takes place through electrophilic substitution reaction

In this reaction the electrophile is nitronium ion (NO2+) which performs an electrophilic substitution reaction on the benzene ring and during the reaction an intermediate will also be formed in which there will be positive charge distributed in the benzene

These electrophile is generated when nitric acid is treated with sulphuric acid

As nitric acid is a strong oxidising agent, here in this case the oxidation state of nitrogen will change from +5 to +3

The reactions regarding the nitration of benzene is present in the file attached

5 0

3 years ago

Oxygen gas is collected at a pressure of 123 kPa in a container which has a volume of 10.0L. What temperature must be maintained

Morgarella [4.7K]

Given:

P = 123 kPa
V = 10.0 L
n = 0.500 moles
T = ?

Assume that the gas ideally, thus, we can use the ideal gas equation:

PV = nRT

where R = 0.0821 L atm/mol K

123 kPa * 1 atm/101.325 kPa * 10.0 L = 0.500 moles * 0.0821 Latm/molK * T

solve for T

T = 295.72 K

5 0

3 years ago

Read 2 more answers