All categories

3 years ago

which statement is true about the reaction shown by this chemical equation HCl + NaOH ------> NaCl + H2O

Chemistry

2 answers:

bixtya [17]3 years ago

7 0

Answer: It is endothermic

Explanation:

NNADVOKAT [17]3 years ago

3 0

Answer:

A. It is exothermic

Explanation:

You might be interested in

How many protons are in the nucleus of an atom with an atomic number of 15

vodomira [7]

Answer:

In the given case, the atomic number of the given atom is 15, hence its nucleus contains 15 protons. The number of protons and electrons are the same in atom and that is what keeps it neutral. In the second case, the atomic number is 20. Hence, the atom will contain a total of 20 protons in its nucleus.

Explanation:

4 0

2 years ago

Read 2 more answers

please help!!! The gravitational force between the objects depends on the __________ of the objects and the ___________ between

postnew [5]

The gravitational force between the objects depends on the mass of the objects and the distance between them.

6 0

3 years ago

Please select the word from the list that best fits the definition growth from seed to plant

Misha Larkins [42]

Is there a picture for this question ?

8 0

3 years ago

Read 2 more answers

Alum is a compound used in a variety of applications including cosmetics, water purification, and as a food additive. It can be

vlabodo [156]

Answer:

The theoretical yield of alum is 19.873 grams and percent yield for this alum synthesis is 45.33%.

Explanation:

Mass of bottle = 10.221 g

Mass of bottle with aluminium pieces = 11.353 g

Mass of aluminium = 11.353 g - 10.221 g = 1.132 g

Mass of alum and bottle = 19.230 g

Mass of alum = 19.230 g - 10.221 g = 9.009 g

Experimental yield of alum = 9.009 g

Theoretical yield of alum:

$2Al(s) +2 KOH(aq) +4H_2SO_4(aq)+10 H_2O(l) \rightarrow 2 KAl(SO_4)_2.12 H_2O(s)+3H_2(g)$

Moles of aluminium = $\frac{1.132 g}{27 g/mol}=0.041926 mol$

According to reaction, 2 moles of aluminum gives 2 moles of alum.

Then 0.041926 mol aluminium will give :

$\frac{2}{2}\times 0.041926 mol=0.041926 mol$ of alum.

Mass of 0.041926 moles of alum:

0.041926 mol × 474 g/mol= 19.873 g

Theoretical yield of alum = 19.873 g

Percentage yield:

$\% Yield =\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Percentage yield of the alum:

$\% Yield =\frac{ 9.009 g}{19.873 g}\times 100=45.33\%$

The theoretical yield of alum is 19.873 grams and percent yield for this alum synthesis is 45.33%.

7 0

3 years ago

What masses of monobasic and dibasic sodium phosphate will you use to make 250 mL of 0.1 M sodium phosphate buffer, pH = 7?

Oduvanchick [21]

Answer:

Mass of monobasic sodium phosphate = 1.857 g
Mass of dibasic sodium phosphate = 1.352 g

Explanation:

The equilibrium that takes place is:

H₂PO₄⁻ ↔ HPO₄⁻² + H⁺ pka= 7.21 (we know this from literature)

To solve this problem we use the Henderson–Hasselbalch (H-H) equation:

pH = pka + $log\frac{[A^{-} ]}{[HA]}$

In this case [A⁻] is [HPO₄⁻²], [HA] is [H₂PO₄⁻], pH=7.0, and pka = 7.21

If we use put data in the H-H equation, and solve for [HPO₄⁻²], we're left with:

$7.0=7.21+log\frac{[HPO4^{-2} ]}{[H2PO4^{-} ]}\\ -0.21=log\frac{[HPO4^{-2} ]}{[H2PO4^{-} ]}\\\\10^{-0.21} =\frac{[HPO4^{-2} ]}{[H2PO4^{-} ]}\\0.616 * [H2PO4^{-}] = [HPO4^{-2}]$

From the problem, we know that [HPO₄⁻²] + [H₂PO₄⁻] = 0.1 M

We replace the value of [HPO₄⁻²] in this equation:

0.616 * [H₂PO₄⁻] + [H₂PO₄⁻] = 0.1 M

1.616 * [H₂PO₄⁻] = 0.1 M

[H₂PO₄⁻] = 0.0619 M

With the value of [H₂PO₄⁻] we can calculate [HPO₄⁻²]:

[HPO₄⁻²] + 0.0619 M = 0.1 M

[HPO₄⁻²] = 0.0381 M

With the concentrations, the volume and the molecular weights, we can calculate the masses:

Molecular weight of monobasic sodium phosphate (NaH₂PO₄)= 120 g/mol.
Molecular weight of dibasic sodium phosphate (Na₂HPO₄)= 142 g/mol.

mass of NaH₂PO₄ = 0.0619 M * 0.250 L * 120 g/mol = 1.857 g

mass of Na₂HPO₄ = 0.0381 M * 0.250 L * 142 g/mol = 1.352 g

5 0

3 years ago