Can someone help me with this please

The heat of hydration is defined as the heat absorbed or evolved when one mole of a substance undergoes hydration. The heat of solution is the enthalpy change associated with he dissolution of a solute. The lattice energy is the heat. Lattice energy is the energy released when the components of the lattice are brought together from infinity.

Hence the heat of solution for LiF → Li^+ + F- is -1966  kJ/mol

Given that;

Heat of hydration = ΔH solution – ΔH lattice energy

Where,

ΔH solution  = Heat of the solution

ΔH lattice energy = Lattice energy of the solution

The heat of solution or enthalpy of dissolution is defined as the enthalpy change associated with the dissolution of a solute in a solvent

From the formula above;

ΔH solution = Heat of hydration + ΔH lattice energy

Heat of hydration = [(-431) + (-499)] = -930 kJ/mol

ΔH solution = (-930) + (-1,036) = -1966  kJ/mol

Hence the heat of solution for LiF → Li^+ + F- is -1966  kJ/mol

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Answer:

oil floats on water because it is heavier than water

Salt is no longer visible after stirring as salt dissolves in water

by filtration

Answer:

6a - 6 - 2a + 4 = 3

4a - 2 = 3

4a = 3 + 2

4a = 5

a = 5/4

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Answer:

Mass of ascorbic acid in the pill = 7.152 x 176.1/1000 = 1.26 g

Explanation:  

The mass of ascorbic acid in the pill would be,  

1.26 g  

Now,  

Moles of ascorbic acid = Moles of NaOH = 0.447 M x 16 ml = 7.152 mmol  

Mass of ascorbic acid in the pill = 7.152 x 176.1/1000 = 1.26 g

Answer:

106 gfm

Explanation:

element. number masses

Na. 2 23×2

C. 1. 12

O. 3. 16×3

then add

106 gfm

Solution:-1

[tex]\\ \sf\longmapsto E=hv[/tex]

Solution:-2

[tex]\boxed{\sf \lambda=\dfrac{c}{v}}[/tex]

[tex]\\ \sf\longmapsto v=\dfrac{c}{\lambda}[/tex]

[tex]\\ \sf\longmapsto v=\dfrac{3\times 10^8m/s}{3000\times 10^{-10}m}[/tex]

[tex]\\ \sf\longmapsto v=0.001\times 10^{18}s^{-1}[/tex]

[tex]\\ \sf\longmapsto v=1.0\times 10^{15}s^{-1}[/tex]

Now

[tex]\\ \sf\longmapsto E=hv[/tex]

[tex]\\ \sf\longmapsto E=6.626\times 10^{-34}Js\times 1.0\times 10^{15}s^{-1}[/tex]

[tex]\\ \sf\longmapsto E=6.6\times 10^{-19}J[/tex]

Explanation:

it is that when an object is moving 25 m per sec to calculate its time we can simply divide 1.5 by 25 and multiply by 1

Answer:

I think it's a sulphate ion, because when you add hydrochloric acid to it it produces bubbles and when you add barium chloride it then produces a white precipitate.its formula is SO4

I hope this helps

Answer: broooo what is this

Explanation:

Answer:

Create a new account as the thing you're experiencing now is due to the fact that Brainly had blocked your account.

Answer:

the reactants are carbon dioxide ,iron, oxygen

The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).

Answer:

We are given that the ring is made up of 20 carrat gold. 20 carrat gold means 20 parts of gold and 4 parts of other metal (usually copper or silver). Thus, the percentage of gold in 20 carrat gold will be

= (20 / 24) X 100

= 83.333 %

We can now calculate the mass of gold in the ring. We are given that the ring weighs 300 mg. So, the mass of gold in ring will be

= (83.333 / 100) X 300

= 250 mg

Thus, the mass of gold in 300 mg of the ring is 250 mg.

Now the molar mass of gold is 197 g. This means that there are 6.023 X 1023 atoms of gold in 197g of gold. Thus

197g of gold = 6.023 X 1023 atoms of gold

1g of gold = (6.023 X 1023 ) / 197 atoms of gold

250 mg or 0.25g of gold = (6.023 X 1023 X 0.25) / 197 atoms of gold

= 7.643 X 1020 atoms of gold

Answer:

They show helixes and proteins

Explanation:

Ribbon diagrams are the Richardson diagrams that represent the protein structures. Chemist prefers using Ribbon diagrams to show the various structure of the proteins.

The Ribbon diagram is used to represent the structural organization of the protein in the polypeptide chains or individually. It shows the three-dimensional structure and organization of the protein framework.

The ribbon diagram for the secondary structure of the protein shows the intramolecular and intermolecular structure along with helixes and bonding. It shows the detailed structure of the protein organization including the helix and sheets.

Therefore, the ribbon diagram is used by chemists to determine the structure of the protein as they give the details about the helix and sheet.

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Answer:

reactivity is NOT a physical property

Answer:

gypsum

Explanation:

gypsum is used to make plaster of Paris

Answer:

Simple squamous epithelium

This type of epithelia lines the inner surface of all blood vessels (endothelium), forms the wall of alveolar sacs in the lung and lines the body cavities (mesothelium). The primary function of simple squamous epithelia is to facilitate diffusion of gases and small molecules.

Explanation:

isme talk kro

Answer:

75%

Explanation:

call realistic moles of N2 in the reaction is a

moles of H2 :3a

moles of NH3: 2a

the moles of residual N2 after reaction: 1-a

the moles of residual H2 after react: 3- 3a

the moles of mixture: 2a+1-a+3-3a=2.5

-> a=0.75

H=0.75/1=75%

Answer: 60 Grams of water are produced, because you can't get more than the amount that was in the original ice cube

Explanation:

Answer:

PH STANDS FOR POTENTIAL OF HYDROGEN .

It represents the ratio of Hydronium ions (H3O) to Hydroxide ions (OH). It is a measure of acidity and alkalinity of a solution.

Answer:

gshshs

Explanation:

bshsjskskehhshs

The copper metal is heated in the air.  The magnesium ribbon emits a brilliant light and magnesium oxide, which is white. When oxygen is passed over copper (in the presence of heat), an oxidation reaction occurs, resulting in the formation of black copper oxide. The greater change in mass observed when they start to burned.

Copper is a mineral and an element that is essential to our daily lives. It is a significant industrial metal due to its high ductility, malleability, thermal and electrical conductivity, and corrosion resistance. It is a necessary nutrient in our diet.

Metals are a class of materials that have high electrical and thermal conductivity, as well as malleability, ductility, and high light reflection. Copper (Cu), aluminium (Al), and other metals are examples.

The combustion of magnesium ribbon is a combined reaction. This is due to the fact that magnesium reacts with oxygen to form the single product magnesium oxide. When magnesium ribbon is burned in air, it reacts with the oxygen in the air to form magnesium oxide.

Thus, 3g of clean mg ribbon and 8g of clean copper metal were burnt separately in equal volume of air and both mass reacted completely with air the greater change in mass observed when they start to burned.

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Answer:

Chlorine (Cl) is most reactive out the the listed elements.

Answer:

iodine

Explanation:

It is the most reactive on the periodic table.

6.94 is much more closet to 7.016, so Li 7 is more abundant

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Answer:

A

Explanation:

the nervous system helps parts of the body communicate.through nerves.

I hope this helps

Answer:

the answer is 47.9 and ik because I just had that question

The empirical formula of the compound is O₄Pb₃.

An Empirical system is the chemical system of a compound that offers the proportions of the elements gifted within the compound however not the real numbers or arrangement of atoms. This would be the lowest complete variety ratio of the elements within the compound.

Amount of lead (Pb) = 90.6%

⇒and amount of oxygen = 9.4%

taking the whole number ratio

o = 4

Pb = 3

∴ ⇒O: Pb=4:3

O4Pb3 answer.

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Answer:

I hope that the link above will be helpful

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[tex]\boxed{\pmb{\green{\sf{2Mg +H_{2}SO_{4}\dashrightarrow H _{2}+Mg_{2}SO_{4}}}}}[/tex]

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The correct answer is D ... and if the answer was added to the word "explode" .. it would have been more correct .

Answer:

can you type question properly.