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2 years ago

Calculate the amount (in grams) of kcl present in 75.0 ml of 2.10 m kcl

1 answer:

5 0

V = 75 mL = 0,075 L = 0,075 dm³
C = 2.1M
n = ?
---------------
C = n/V
n = C×V
n = 2.1×0,075
n = 0,1575 mol
--------
mKCl: 39+35.5 = 74,5 g/mol

74,5g --------- 1 mol
Xg ------------- 0,1575 mol
X = 74,5×0,1575
X = 11,73375g KCl

:•)

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When applied to a dish, soap makes grease soluble in water. Which explanation correctly supports the role of intermolecular forc

Mekhanik [1.2K]

Explanation:

Soaps attach to both water and grease molecules.

The grease molecules are attracted more strongly towards each other as compared to water molecules. Also, water molecules are smaller in size hence, strong intermolecular force is required to break the hydrogen bonds of water molecule so that grease or oil molecules can enter the water molecule.

A soap molecule goes in between water and grease molecule and helps them to bind. The force for linkage between water and grease molecule through the soap molecule is weak london dispersion force.

The soap molecule has its salt end as ionic and water soluble. When grease or oil is added to the soap and water solution then the soap acts as an emulsifier. The soap forms miscelles of the non-polar tails and grease molecules are trapped between these miscelles. This miscelle is easily soluble in water hence, the grease is washed away.

Thus, it can be concluded that the nonpolar end of a soap molecule attaches itself to grease.

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1 year ago

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Only one isotope of this element occurs in nature. one atom of this isotope has a mass of 9.123 ✕ 10-23 g. identify the element

o-na [289]

The atom has only one isotope which means 100 % of same atom is present in nature. The atomic mass of an element is the number of times an atom of that element is heavier than an atom of carbon taken as 12. Mass of one atom of that isotope is 9.123 ✕ 10⁻²³ g, so mass of one mole of atom that is Avogadro's number of atom is 6.023 X 10²³ X 9.123 X 10⁻²³ g=54.94 g = 55 g (approximate).

So, the atom having atomic mass 55 will be Cesium (Cs). Only one isotope of Cesium is stable in nature.

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1 year ago

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Neutrons were discovered in 1932, more than 10 years after the existence of isotopes was confirmed. What property of electrons a

kirza4 [7]

Protons and neutrons are the sub-atomic particles present in the nucleus of an atom where as electrons are present revolving round the nucleus in orbits. Electrons are negatively charged, protons are positively charged where as a neutron is a neutral species. It is the presence of electric charge that lead to the discovery of electrons (negative charge) and protons (positive charge), while it took time to discover neutral as they were electrically neutral species. Neutrons carrying no charge were not detected easily by passing electromagnetic radiations. Therefore, neutrons were the last of the three subatomic particles, to be discovered.

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2 years ago

You might be able to roughly estimate mass in a visual manner, but it could be easy to dismiss the fact that a mole or even a gr

qwelly [4]

The balanced equation is

CO(g) + 2H2 (g) -> CH3OH(l)

Which means, every 2 moles of H2 will react with 1 mole of CO.

Find the number of moles, n = m/Mr

CO = (1.5x10^-6)/(12) = 1.25 x 10^-7 mol

H2 = (6.8x10^-6)/(2) = 3.4 x 10^-6 mol

Since we have a mole ratio of 2 to 1, H2 value will be multipled by 2 as 2 moles of H2 react to 1 mole of CO.

3.4 x 10^-6 x 2 = 6.8 x 10^-6

So obviously we can see that H2 is in excess and only some H2 molecules will be left at the end of the reaction.

6.8 x 10^-6 - 1.25 x 10^-7 = 6.675 x 10^-6 Moles of unreacted H2

To find the molecules of this amount of moles, Multiply it by Avogadros number, 6.02 x 10^23

Because for every mole, there are 6.02 x 10^23 molecules

6.575 x 10^-6 x 6.02 x 10^23 = 3.96 x 10^ 18 Molecules of gas

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2 years ago

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NO2 can react with the NO in smog, forming a bond between the N atoms. Draw the structure of the resulting compound, including f

ELEN [110]

First, let's write down the balanced chemical reaction between the given reactants:

NO₂ + NO → N₂O + O₂

The Lewis structure of the main product is shown in the attached picture. To determine the formal charge of each element, the formula is as follows:

Formal Charge = Valence electrons - Non-bonding valence electrons - (Bonding electrons/2)

For the leftmost N:
Formal charge = 5 - 2 - 6/2 = 0
For the middle N:
Formal charge = 5 - 0 - 8/2 = 1
For O:
Formal charge = 6 - 6 - 2/2 = -1

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1 year ago