Answer:
1. 192.0 g/mol.
2. 84.0 g/mol.
Explanation:
- <em>The molar mass is the mass of all the atoms in a molecule in grams per mole.</em>
- <em>To calculate the molar mass of a molecule, we first obtain the atomic weights from the individual elements in a periodic table. We then count the number of atoms and multiply it by the individual atomic masses.</em>
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<em>1. Molar mass of citric acid (C₆H₈O₇):</em>
<em>Molar mass of C₆H₈O₇ = 6(atomic mass of C) + 8(atomic mass of H) + 7(atomic mass of O)</em> = 6(12.0 g/mol) + 8(1.0 g/mol) + 7(16.0 g/mol) = <em>192.0 g/mol.</em>
<em>2. Molar mass of baking soda (NaHCO₃):</em>
<em>Molar mass of NaHCO₃ = (atomic mass of Na) + (atomic mass of H) + (atomic mass of C) + 3(atomic mass of O) </em>= (23.0 g/mol) + (1.0 g/mol) + (12.0 g/mol) + 3(16.0 g/mol) = <em>84.0 g/mol.</em>
Answer : The pH of a 0.1 M phosphate buffer is, 6.86
Explanation : Given,
Concentration of acid = 0.1 M
Concentration of conjugate base (salt) = 0.1 M
Now we have to calculate the pH of buffer.
Using Henderson Hesselbach equation :
![pH=pK_a+\log \frac{[Salt]}{[Acid]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BSalt%5D%7D%7B%5BAcid%5D%7D)
Now put all the given values in this expression, we get:
Therefore, the pH of a 0.1 M phosphate buffer is, 6.86
Answer:
The correct answer is - hard water reacts to form the calcium or magnesium salt of the organic acid of the soap.
Explanation:
Soaps are made up of fatty acids or oils by treating with strong alkali and are salts of sodium and potassium. Hard water, on the other hand, has a high concentration of minerals in comparison to soft water. When hard water and soap are mixed together the salts of the minerals like Ca2+ and Mg2+ ions present in hard water react with fatty acids of the soap.
The sodium salts are changed to the salts of calcium and magnesium which are precipitated to an insoluble substance. The insoluble salts of the calcium or magnesium dirt stick on the clothes thus cleaning ability of soap is reduced.
<span><span>N2</span><span>O5</span></span>
Explanation!
When given %, assume you have 100 g of the substance. Find moles, divide by lowest count. In this case you'll end up with
<span><span>25.92 g N<span>14.01 g N/mol N</span></span>=1.850 mol N</span>
<span><span>74.07 g O<span>16.00 g O/mol O</span></span>=4.629 mol O</span>
The ratio between these is <span>2.502 mol O/mol N</span>, which corresponds closely with <span><span>N2</span><span>O5</span></span>.
Answer:
b,d
Explanation:
An ion is an atom with a difference in the amount of protons and elektrons.
