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3 years ago

Assuming complete dissociation, what is the pH of a 4.82 mg/L Ba(OH)2 solution?

1 answer:

4 0

Ba(OH)₂ is a strong base and completely ionises into its corresponding ions
Ba(OH)₂ ---> Ba²⁺ + 2OH⁻
1 mol of Ba(OH)₂gives 2 mol of OH⁻ ions.
molarity of Ba(OH)₂ is 4.82 x 10⁻³ g/L / 171.3 g/mol - 2.81 x 10⁻⁵ mol/L
since 1 mol of Ba(OH)₂gives 2 mol of OH⁻ ions.
therefore [OH⁻] = 2[Ba(OH)₂]
[OH⁻] = 2 x 2.81 x 10⁻⁵ mol/L = 5.62 x 10⁻⁵ M
pOH can be calculated using the OH⁻ concentration
pOH = -log [OH⁻]
pOH = - log (5.62 x 10⁻⁵ M)
pOH = 4.25
pH can be calculated as follows
pH + pOH = 14
pH = 14 - 4.25
pH = 9.75
pH of solution is 9.75

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Calculate the specific heat of a piece of wood if 2000 g of wood absorbs 75,250 J of heat, and its temperature changes from 30°C

inna [77]

Answer:

Explanation:

The specific heat capacity=quantity of heat in joule/mass×change in temperature

from this question the quantity of heat is 75250,the mass is 2000 and the change in temperature is 50-30

which is 20

therefore

c=75250/2000×20

c=75250/40000

c=1.88

I hope this helps

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3 years ago

A solution is prepared by dissolving 91.7 g fructose in 545 g of water. Determine the mole fraction of fructose if the final vol

oee [108]

Answer:

Mole fraction = 0,0166

Explanation:

Mole fraction is defined as mole of a compound per total moles of the mixture. In the solution, the solute is fructose and the solvent is water. That means you need to find moles of fructose and moles of water.

The molecular mass of fructose is 180,16g/mol and mass of water is 18,02 g/mol. Using these values:

91,7g fructose × (1mol / 180,16g) = 0,509 moles of fructose

545g water × (1mol / 18,02g) = 30,24 moles of water

Thus, mole fraction of fructose is:

$\frac{0,509 moles}{0,509mol + 30,24mol} = 0,0166$

Mole fraction = 0,0166

I hope it helps!

5 0

3 years ago

Elemental mercury combines with oxygen to make mercury oxide. write a balanced equation

Ilia_Sergeevich [38]

Hg + O2 --> HgO + O

Note that Mercury has a variable valency.

6 0

3 years ago

While finding the number of molecules of oxygen molecules present in 3.65 moles of Na2SO4 the conversion factor used would be

zvonat [6]

Answer

Avogadro's number: One mole of any substance contains 6.022×10²³ molecules

Explanation

While finding the number of moles of oxygen molecules present in 3.65 moles of Na2SO4 the conversion factor used would be Avodagro's number, which is

One mole of any substance contains 6.022×10²³ molecules.

8 0

1 year ago

J. Explain how an atom's valence electron configuration determines its place on the periodic table.

Darya [45]

Answer:

Elements having same valence electrons are placed in same group.

Explanation:

First, let's start with some basic concepts of modern periodic table:

1. Modern Periodic table : It is the arrangement of element in the increasing order of their atomic numbers

The Modern periodic table is divided into Periods and groups .

Periods : These are the horizontal rows. There are seven periods in the periodic table . Period 1 has 2 element. Period two and three has 8 elements , period 4 and 5 have 18 elements and the period 6 and 7 have 32 elements.

Same period have same number of atomic orbital(Shell)

Group : The group is the vertical columns . There are 18 groups in the modern periodic table.Those element which have same group number will also have same number of electron in their outermost shell. The number of electron in the outermost shell determines the valency of the element.

So, elements showing same valency are placed in same group.

All alkali are place in group 1 and have 1 valance electron in the outermost shell

5 0

4 years ago