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3 years ago

Describe the difference between a reaction that occurs spontaneously and one that does not

1 answer:

4 0

2.B. Describe the difference between a reaction that occurs spontaneously and one that does not. Spontaneous chemical reactions release energy and use that energy to power itself; non-spontaneous chemical reactions need to absorb energy, which they can't absorb their own energy that they don't even have.

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In solid NaCl, the equilibrium separation between neighboring Na+ and Cl- ions is 0.283 nm. Calculate the coulombic energy betwe

const2013 [10]

Explanation:

It is given that r = 0.283 nm. As 1 nm = $10^{-9} m$ .

Hence, 0.283 nm = $0.283 \times 10^{-9} m$

Formula for coulombic energy is as follows.

$U_{coulomb} = -1.748 \frac{e^{2}}{4 \pi \epsilon_{o} r}$

where, e = $1.6 \times 10^{-19}$ C

$\epsilon_{o}$ = $8.85 \times 10^{-12}$

$U_{coulomb} = -1.748 \frac{(1.6 \times 10^{-19}^{2}}{4 \times 3.14 \times 8.85 \times 10^{-12} \times 0.283 \times 10^{-9}}$

= $1.423 \times 10^{-18} J$

As 1 eV = $1.6 \times 10^{-19} J$

So, 1 J = $\frac{1 eV}{1.6 \times 10^{-19}}$

Hence, U = $\frac{1.423 \times 10^{-18} J}{1.6 \times 10^{-19} J}$

= 8.9 eV

Also, 1 J = $\frac{10^{-3} kJ}{6.022 \times 10^{23}mol}$

= $1.67 \times 10^{-27}$ kJ/mol

Therefore, U = $1.423 \times 10^{-18} J \times 1.67 \times 10^{-27}$ kJ/mol

= $2.37 \times 10^{-45} kJ/mol$

7 0

3 years ago

How many moles of hydrogen gas can be produced if 0.78 moles of hydrochloric acid reacts with excess solid zinc according to the

White raven [17]

Answer:

The answer to your question is It will be formed 0.39 moles of H₂

Explanation:

Data

moles of H₂ = ?

moles of HCl = 0.78

moles of Zinc = excess

Balanced chemical reaction

2 HCl + Zn ⇒ 1 H₂ + ZnCl₂

Process

1.- Use proportions to solve this problem. Consider the coefficients of the balanced reaction.

2 moles of HCl ---------------------- 1 mol of H₂

0.78 moles of HCl ----------------- x

x = (0.78 x 1) / 2

- Simplification

x = 0.78 / 2

- Result

x = 0.39 moles of H₂

3 0

3 years ago

Jia observes that adding a solution of sodium hydroxide to a clear liquid turns the liquid pink. She makes a hypothesis about wh

Oksana_A [137]

The question is incomplete, the complete question is;

Jia observes that adding a solution of sodium hydroxide to a clear liquid turns the liquid pink. She makes a hypothesis about why the liquid changed color.

Which characteristic is least important for her hypothesis to have?

A)ability to be tested

B)based on the opinion of her classmates

C)ability to be proven incorrect

D)based on her current knowledge

Answer:

B)based on the opinion of her classmates

Explanation:

A hypothesis is a supposition or tentative explanation put forward based on minimal evidence. It sometimes sets the pace for further investigation.

Hypothesis is always based on empirical observation and not on popular opinion, hence the opinion of Jia's classmates is least important in Jia's formulation of a hypothesis.

3 0

3 years ago

4.96 megameters to inches show work

pentagon [3]

There has to be something else then just what you said

4 0

3 years ago

If 50.0 g of formic acid (hcho2, ka = 1.8 x 10^-4) and 30.0 g of sodium formate (NaCHO2) are dissolved to make 500 ml. of soluti

gizmo_the_mogwai [7]

If 50.0 g of formic acid (HCHO2, ka = 1.8 x 10^-4) and 30.0 g of sodium formate (NaCHO2) are dissolved to make 500 ml. of solution, the ph of this solution is 3.35.

Therefore, option C is the correct option.

Given,

Given mass of sodium formate = 30 g

Given mass of formic acid = 50 g

Volume of sodium formate = 500 ml

Volume of formic acid = 500ml

Molar mass of sodium formate = 68 g

Molar mass of formic acid = 46 g

<h3>To calculate concentration of sodium formate and formic acid</h3>

The ratio of number of moles and the volume of solution is Molar concentration of substance.

Concentration of sodium formate

Cb = 30/(68×500)

= 0.00088m

Concentration of formic acid

Ca = 50/(46×500)

= 0.00217m

Now,

by using Henderson hesselbalch equation,

pH = pKa + log(Cb/Ca)

pKa = -log(1.8 × 10^(-4))

= 3.75

pH = 3.75 + log(0.00088/0.00217)

pH = 3.75 - 0.392

pH = 3.35

Thus, we calculated that the value of pH of solution of formic acid and sodium formate is 3.35.

learn more about pH:

brainly.com/question/13423434

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3 0

2 years ago