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3 years ago

As NH4Cl dissolves in water, and cools the solution,

Chemistry

1 answer:

azamat3 years ago

5 0

Answer:

d. delta H is positive, and delta S is positive

Explanation:

The process of dissolution of NH4Cl is:

NH4Cl(s) → NH4+(aq) + Cl-(aq)

As the solution is cooled, the process is absorbing energy, that means ΔH > 0. (ΔH < 0 when the heat is released).

As there are produced 2 ions from 1 solid molecule, the disorder is increasing and ΔS > 0

The right answer is:

<h3>d. delta H is positive, and delta S is positive</h3>

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A chemical reaction is done in the setup shown , resulting in a change of mass. What will happen if the same reaction is done in

irina1246 [14]

<h2>Answer:</h2>

The mass of the system will remain the same if there is no conversion of mass to energy in the reaction.

<h3>Explanation:</h3>

If the system is closed, then according to the law of mass conservation the mass of the reaction system will remain the same.
<u><em>Law of conservation of the mass: In simple words, it is described as the mass of a closed system can never be changed, it may transfer from one form to another or change into energy.</em></u>
But if the reaction involves energy transfer like heat or light production, in this case, the mass can be changed.

5 0

3 years ago

Read 2 more answers

What's the electron configuration of an N-3 ion?

WARRIOR [948]

Answer:

A. since Nitrogen has 7 electrons and when it gains 3 electrons it will have 10 electrons. using short hand rule it is [Ne]

8 0

3 years ago

The density of the hydrocarbon in part (a) is 2.0 g l-1 at 50°c and 0.948atm. (i) calculate the molar mass of the hydrocarbon. (

Vedmedyk [2.9K]

1. Answer;

=56 g/mol

Explanation and solution;

PV = nRT

nRT= mass/molar mass (RT)

molar mass = (mass/V ) × (RT/P)

= Density × (RT/P)

Molar mass = 2.0 g/L × (0.0821 × 323 K)/0.948 atm

Molar mass = 56 g/mol

2. Answer;

Molecular mass is C4H8

Explanation;

Empirical mass × n = molar mass

Empirical mass for CH2 = 14 g/mol

Therefore;

56 g/mol = 14 g/mol × n

n = 4

The molecular formula= 4(CH2)

= C4H8

7 0

3 years ago

You have 50 ml of a complex mixture of weak acids that contains some HF (pKa = 3.18) and some HCN (pKa = 9.21). Which is larger,

bonufazy [111]

Answer:

$\frac{[F^{-}]}{[HF]}$ is larger

Explanation:

$pK_{a}=-logK_{a}$ , where $K_{a}$ is the acid dissociation constant.

For a monoprotic acid e.g. HA, $K_{a}=\frac{[H^{+}][A^{-}]}{[HA]}$ and $\frac{[A^{-}]}{[HA]}=\frac{K_{a}}{[H^{+}]}$

So, clearly, higher the $K_{a}$ value , lower will the the $pK_{a}$

In this mixture, at equilibrium, $[H^{+}]$ will be constant.

$K_{a}$ of HF is grater than $K_{a}$ of HCN

Hence, $(\frac{F^{-}}{[HF]}=\frac{K_{a}(HF)}{[H^{+}]})>(\frac{CN^{-}}{[HCN]}=\frac{K_{a}(HCN)}{[H^{+}]})$

So, $\frac{[F^{-}]}{[HF]}$ is larger

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3 years ago

Which of the following is an

eimsori [14]

Answer:

2 and 4

Explanation:

The rest of the changes are chemical. 1 has a chemical reaction happen which makes light sticks glow. 3 is because browning the meat actually causes some new compounds to form and cause caramelization.

For 2, the oxygen is simply heating up and expanding which pops the balloon. 4 is just a phase change of water vapor to liquid water.

5 0

3 years ago