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3 years ago

Vhat is the molarity of an Nal solution that contains 7.0 g of Nal in 23.0 mL of solution?

Chemistry

1 answer:

Alika [10]3 years ago

4 0

Answer:

Molarity = 5.22 M

Explanation:

Given data:

Mass of sodium chloride = 7.0 g

Volume of solution = 23.0 mL ( 23.0/1000 = 0.023 L)

Molarity = ?

Solution;

Number of moles of NaCl = 7.0 g/ 58.4 g/mol

Number of moles of NaCl = 0.12 mol

Molarity = moles of solute / volume in litter

Molarity = 0.12 mol / 0.023 L

Molarity = 5.22 M

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Calculate the pH of a buffer solution that contains 0.25 M benzoic acid (C 6H 5CO 2H) and 0.15M sodium benzoate (C

gtnhenbr [62]

Answer:

$pH=3.97$

Explanation:

Hello,

In this case, for the calculation of the pH of the given buffer we need to use the Henderson-Hasselbach equation:

$pH=pKa+log(\frac{[base]}{[acid]} )$

Whereas the pKa for benzoic acid is 4.19, the concentration of the base is 0.15 M (sodium benzoate) and the concentration of the acid is 0.25 M (benzoic acid), therefore, the pH turns out:

$pH=4.19+log(\frac{0.15M}{0.25M} )\\\\pH=3.97$

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4 0

3 years ago

In the reaction 2 H2 + O2m 2 H20, how

Tresset [83]

Answer:

Option F. 3moles

Explanation:

The equation for the reaction is given below:

2H2 + O2 —> 2H2O

from the equation,

2moles of H2 required 1mole of O2.

Therefore, 6moles of H2 will require = 6/2 = 3moles of O2

8 0

3 years ago

Read 2 more answers

Both kepler's laws and newton's laws tell us something about the motion of the planets, but there are fundamental differences be

I am Lyosha [343]

Answer: See description

Explanation:

Kepler's laws have three principal points:

1. planets orbit the sun in elliptical paths

2. the orbial period is related to the orbital distance by $T^{2} = d^3$

where T is the orbital period and d is the orbital distance, T is in years and d is measured in units of the earth sun distance.

3. planets closer to the sun move faster than planets far away from it.

Newton:

Newton discovered that there is a consequence to the gravity exerted by objects: mass, the heavier the planet, the more gravitational force it posseses ( thats why we orbit the sun)

with the gravitational force $F_{gravitational} =G \frac{Mm}{r^2}$ newton discovered the inverse-quadratic relationship between the distance of the planets and the acceleration exerted by the force one could exert on another.

Kepler's laws were mostly based on observed evidence with quantitative relationships between the mentioned variables. Newton's laws are based on calculus and symbolic equations. While Kepler's mode is basic, Newton took another step in and build a more general model for gravity (which was improved by general relativity later). In a nutshell Newton proved the scientific causes for Kepler's laws...

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3 years ago

Lactic acid results from which of the following?

vazorg [7]

Explanation:

Lactic acid is formed during the breakdown of glucose. This is sometimes called "blood sugar."

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3 years ago

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Gallium is produced by the electrolysis of a solution made by dissolving gallium oxide in concentrated NaOH ( aq ) . Calculate t

Sedbober [7]

Answer:

Approximately $6.30\times 10^{-3}\;\rm mol$ .

Explanation:

The gallium here is likely to be produced from a $\rm NaGaO_2\, (aq)$ solution using electrolysis. However, the problem did not provide a chemical equation for that process. How many electrons will it take to produce one mole of gallium?

Note the Roman Numeral " $\mathtt{(III)}$ " next to $\rm Ga$ . This numeral indicates that the oxidation state of the gallium in this solution is equal to $+3$ . In other words, each gallium atom is three electrons short from being neutral. It would take three electrons to reduce one of these atoms to its neutral, metallic state in the form of $\rm Ga\, (s)$ .

As a result, it would take three moles of electrons to deposit one mole of gallium atoms from this gallium $\mathtt{(III)}$ solution.

How many electrons are supplied? Start by finding the charge on all the electrons in the unit coulomb. Make sure all values are in their standard units.

$t = \rm 80.0\; min = 80.0\; min \times 60\;s \cdot min^{-1} = 4800\; s$ .

$Q = I \cdot t = \rm 0.380 \; A \times 4800 \; s = 1.824\times 10^3\; C$ .

Calculate the number of electrons in moles using the Faraday's constant. This constant gives the size of the charge (in coulombs) on each mole of electrons.

$\begin{aligned} n(\text{electrons}) &= \frac{Q}{F} \cr &= \rm \dfrac{1.824\times 10^3\; C}{96485.332\; C \cdot mol^{-1}}\cr &\approx \rm 1.89\times 10^{-2}\; mol \end{aligned}$ .

It takes three moles of electrons to deposit one mole of gallium atoms $\rm Ga\, (s)$ . As a result, $\rm 1.89\times 10^{-2}\; mol$ of electrons would deposit $\displaystyle \rm \frac{1}{3}\times 1.89\times 10^{-2}\; mol \approx 6.30\times 10^{-3}\; mol$ of gallium atoms $\rm Ga\, (s)$ .

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2 years ago