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3 years ago

Which of the following processes involves an increase in entropy?

Chemistry

2 answers:

balandron [24]3 years ago

8 0

Melting gold bars is the process that involves an increase in entropy

maria [59]3 years ago

7 0

Answer: melting gold bars

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

1. Condensing water vapor: gaseous phase is being converted to liquid phase, thus the randomness is decreasing.

2. Melting gold bars: Solid phase is being converted to liquid phase, thus the randomness is increasing.

3. filtering grounds from coffee: The randomness is decreasing as some particles are being removed.

4. freezing popsicles: liquid phase is converting to solid phase, thus the randomness is decreasing.

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Which of the following polyatomic ions will form an ionic compound with two sodium ions? CO32− HCO31− NO21− NO31−

BaLLatris [955]

Answer:

CO32−

Explanation:

We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.

When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;

2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)

8 0

3 years ago

A student is given a 2.002 g sample of unknown acid and is told that it might be butanoic acid, a monoprotic acid (HC4H7O2, equa

Elina [12.6K]

Answer: The identity of the unknown acid is butanoic acid or ascorbic acid.

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}$

Molarity of NaOH solution = 0.570 M

Volume of solution = 39.55 mL

Putting values in above equation, we get:

$0.570M=\frac{\text{Moles of NaOH}\times 1000}{39.55}\\\\\text{Moles of NaOH}=\frac{0.570\times 39.55}{1000}=0.0225mol$

The chemical equation for the reaction of NaOH and monoprotic acid follows:

$NaOH+HX\rightarrow NaX+H_2O$

By Stoichiometry of the reaction:

1 mole of NaOH reacts with 1 mole of HX

So, moles of monoprotic acid = 0.0225 moles

The chemical equation for the reaction of NaOH and diprotic acid follows:

$2NaOH+H_2X\rightarrow 2NaX+2H_2O$

By Stoichiometry of the reaction:

2 moles of NaOH reacts with 1 mole of diprotic acid

So, moles of diprotic acid = $\frac{0.0225}{2}=0.01125moles$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

For butanoic acid:

Mass of butanoic acid = 2.002 g

Molar mass of butanoic acid = 88 g/mol

Putting values in above equation, we get:

$\text{Moles of butanoic acid}=\frac{2.002g}{88g/mol}=0.02275mol$

For L-tartaric acid:

Mass of L-tartaric acid = 2.002 g

Molar mass of L-tartaric acid = 150 g/mol

Putting values in above equation, we get:

$\text{Moles of L-tartaric acid}=\frac{2.002g}{150g/mol}=0.0133mol$

For ascorbic acid:

Mass of ascorbic acid = 2.002 g

Molar mass of ascorbic acid = 176 g/mol

Putting values in above equation, we get:

$\text{Moles of ascorbic acid}=\frac{2.002g}{176g/mol}=0.01137mol$

As, the number of moles of butanoic acid and ascorbic acid is equal to the number of moles of acid getting neutralized.

Hence, the identity of the unknown acid is butanoic acid or ascorbic acid.

5 0

3 years ago

What happens when two positively charged objects move closer to each other?

Katena32 [7]

Answer: Objects with like charge repel each other.

6 0

3 years ago

Read 2 more answers

What is the number of the group that has the most reactive nonmetals (give number and letter- Ex 1A, 2A, etc.)?

Kryger [21]

Answer:

Group 7A

Explanation:

The group 7A elements consists of the most reactive non-metals on the periodic table.

This group is known as the group of halogens. They consist of element fluorine, chlorine, bromine, iodine and astatine.

The elements in this group have the highest electronegativity values.
They have 7 valence electrons and requires just one electron to complete their octets.
This way, they are highly reactive in their search for that single electron.

3 0

3 years ago

If the two atoms participating in a bond have an electron negativity difference of 1.9 , what type of of bond would they be part

brilliants [131]

Answer:

Polar covalent bond.

Explanation:

When the bond is formed between the atoms by sharing the electrons the bond thus have covalent character. The atom with larger electronegativity attract the electron pair more towards it self and becomes partial negative while the other atom becomes partial positive. When the electronegativity difference is less than 0.4 the bond is non polar covalent.

When bonded atoms have greater electronegativity difference i.e 2 or greater than two the bond is ionic because electron is transfer from low electronegative atom to highest electronegative atom.

For example:

In water the electronegativity of oxygen is 3.44 and hydrogen is 2.2. That's why electron pair attracted more towards oxygen, thus oxygen becomes partial negative and hydrogen becomes partial positive.

In case of H₂, Cl₂, Br₂ the bond has very high covalent character because of zero electronegativity difference.

7 0

3 years ago