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3 years ago

approximately how many grams of sodium chloride (NaCl) are required to prepare 500. mL of 3.00 M solution

1 answer:

4 0

3.00 M means 3.00 mol/L. So if you want 500 mL=0.5 L, it needs 3.00 mol/L * 0.5 L = 1.50 mol. For NaCl, the molar mass is 23+35.5=58.5 g/mol. So the amount of NaCl needed is 1.50*58.5=87.75 g. So the answer is 87.75 grams.

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I need help with balancing equations I'm doing homework and idk what to do here can you give me the answers please lol

amm1812

It's pretty easy to balance equations! Basically you want to make sure that the number of each compound is equal on both sides of the arrow.

For example number one is

Fe + H2SO4 -> Fe2(SO4)3 + H2

A 3 in front of H2SO4 because there's a subscript of 3 on the right side.

Then a 3 in front of H2 because of the previous step.

Then add a 2 in front of Fe because of the 2 subscript in Fe2(SO4)3

Then add a 1 in front of Fe2(SO4)3 because you already have an equal number of each element.

2Fe + 3H2SO4 -> 1Fe2(SO4)3 + 3H2

I hope this explanation helps! You should really do your homework because practice is everything when it comes to chemistry. You'll need to know how to do it for exams.

3 0

3 years ago

Calculate the cell potential, E, for the following reactions at 26.29 °C using the ion concentrations provided. Then, determine

yanalaym [24]

Answer:

I will work only one of the listed equations ... you follow the given example for the remaining reactions. Thank you :-)

Rxn 1: Pt°(s) + Fe⁺²(aq) ⇄ Pt⁺²(aq) + Fe°(s)

a) E(Pt⁺²/Fe°) = - 1.668v

b) Process is Non-spontaneous if E(cell) < 0

Explanation:

Pt°(s) + Fe⁺²(aq) ⇄ Pt⁺²(aq) + Fe°(s) ⇔

Pt°(s)|Pt⁺²[0.057M]║Fe⁺²[0.006M]|Fe°(s)

As written, Pt° is shown undergoing oxidation with Fe⁺² undergoing reduction. Applying the reduction potentials to the analytical equations for E(cell) and ΔG(cell) gives E(Pt/Fe⁺²) < 0 and ΔG(Pt/Fe⁺²) > 0 which indicate a non-spontaneous process. The following supports this conclusion.

E°(Fe⁺²) = -0.44v

E°(Pt⁺²) = +1.20v

E°(Pt/Fe⁺²) =E°(Redn) - E°(Oxidn) =E°(Fe⁺²) - E°(Pt⁺²)

= -0.44v - (+1.20v) = - 1.64v

[Fe⁺²] = 0.0066M

[Pt⁺²] = 0.057M

n = electrons transferred = 2

E(nonstd) = E°(std) - (0.0592/n)logQ);

Q = [Pt⁺²]/[Fe⁺²]

= -1.64v - (0.0592/2)log[0.057M]/[0.006M]v = -1.668v

Also, if ΔG(cell) > 0 => indicates non-spontaneous process

ΔG(Pt/Fe⁺²) = - nFE = -(2)(96,500Coulombs)((-1.664v) > 0 Kj => nonspontaneous rxn. (1 Coulomb-volt = 1 Kilojoule)

7 0

3 years ago

A chemist mixes 1.00 g CuCl2 with an excess of (NH4)2HPO4 in dilute aqueous solution . He measures the evolution of 670 J of hea

kaheart [24]

Answer:

$\Delta H$ will be 90054 J

Explanation:

Number of moles = (mass)/(molar mass)

Molar mass of $CuCl_{2}$ = 134.45 g/mol

So, 1.00 g of $CuCl_{2}$ = $\frac{1.00}{134.45}mol$ of $CuCl_{2}$ = 0.00744 mol of $CuCl_{2}$

0.00744 mol of $CuCl_{2}$ produces 670 J of heat

So, 1 mol of $CuCl_{2}$ produces $\frac{670}{0.00744}J$ of heat or 90054 J of heat

4 0

3 years ago

Hannah does an experiment. She has two colorless chemicals that she mixes together in a beaker. Which of the following indicates

uranmaximum [27]

I am not to sure but is it all 4 of them?

8 0

3 years ago

Read 2 more answers

Place the following elements in order of increasing electronegativity.K Cs PA. K < P < CsB. P < Cs < KC. Cs < K &

skad [1K]

Answer:

C. Cs < K < P

Explanation:

Electronegativity is the basically the tendency of an atom to attract electrons. The pauling scale is used to quantify electronegativity, the most electronegative element; fluorine has a value of 4.0 and francium, the least electronegative element has a value of 0.7

The electronegative values of the following elements are given as;

K = 0.82

Cs =0.79

P = 2.19

Arranging in order of increasing electronegativity, we have;

Cs < K < P. The correct option is;

C. Cs < K < P

5 0

3 years ago