Urgent please help
A.Ca
B. CaO
C.CO

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

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:

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Answer:

Los alimentos para evitar la fatiga durante una carrera son alimentos bajos en grasas y altos en carbohidratos, así como alimentos bajos en fibra como pan, mantequilla de maní, plátano, jugo de frutas sin pulpa, y beber hasta aproximadamente 600 ml de líquido aproximadamente 3 horas. antes de la carrera

La comida para comer unos días antes de la carrera incluye carnes magras, arroz, pasta y verduras con contenido de almidón.

Los alimentos que se deben evitar incluyen carne roja, alimentos con alto contenido de grasas saturadas, alimentos fritos, pasteles y salchichas.

Explanation:

Answer:

solubility of salt at 10 degree Celsius is 20 how does it what does it means what happens if the temperature of saturated solution is increased

Explanation:

solubility of salt at 10 degree Celsius is 20 how does it what does it means what happens if the temperature of saturated solution is increased

Answer:

15.3g

Explanation:

C6H12O6 → 2C2H5OH + 2CO2

1 mol C6H12O6 = 180g

1 mol CH3-CH2-OH = 46g

From 180g glucose ethanol can get = 92g

30g glucose ethanol gives us = (92*30)/180 = 15.33g

Explanation:

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Answer:

The volume of NO is 22.4L at STP

Explanation:

Based on the reaction:

2NH3 + 5/2O2 → 2NO + 3H2O

2 moles of NH3 react with 5/2 moles of O2 to produce 2 moles of NO.

To solve this question, we need to find the moles of each reactant in order to find the limiting reactant as follows:

Moles NH3 -Molar mass: -17.01g/mol-

Using PV = nRT

PV/RT = n

Where P is pressure = 1atm at STP

V is volume = 22.4L

R is gas constant = 0.082atmL/molK

T is absolute temperature = 273.15K

1atm*22.4L/0.082atmL/molK*273.15K = n

n = 1.00 moles of NH3

For a complete reaction of 1.00 moles of NH3 are needed:

1.00 moles NH3 * (5/2moles O2 / 2moles NH3) = 1.25 moles of O2

As there are 1.406 moles of O2, the limiting reactant is NH3

The moles of NO produced are the same than moles of NH3 because 2 moles of NH3 produce 2 moles of NO. The moles of NO are 1.00 moles

And as 1.00moles of gas are 22.4L at STP:

Answer:

Some examples of solutions are salt water, rubbing alcohol, and sugar dissolved in water. ... In our example of salt water, the solute is the salt. Solvent: this is the substance that makes up the majority of the solution. This is the part where the solute is dissolved.

Explanation:

I hope they should be right answer

Answer:

the answer will be number...D

Answer:

The answer is A

Explanation:

Because dandelions are wispy and very light, the slightest gasp of wind helps carry the dandelions to new locations and help reproduce the seed into a new dandelion.

Answer: d. have the silicon-oxygen tetrahedron as their structural unit.

Explanation:

Silicates are anions that have both Oxygen and Silicon as the basis of their structure. These two form a tetrahedron type structure that enable them to be useful for a whole lot of things.

Silicates are very abundant on Earth as they comprise around 95% of the Earth's crust as well as the upper mantle which explains why they are mostly found in igneous rocks.

Answer:

Model

Explanation:

A model of anything is something you make to represent it in it's physical world form

Answer:

4i[tex]\sqrt{5}[/tex]

Explanation:

[tex]i^{2}[/tex]= -1

Answer:

B. Lithium (Li) and iodine (1)

Explanation:

Ionic bond is a type of chemical bond that is formed between a metallic element and a non metallic element. The positive charge of the metallic ion is attracted to the negative charge of the non metallic ion to form an ionic bond.

According to the options given in this question, lithium and iodine will form an IONIC bond because lithium is a cation (+ve ion) while iodine is an anion (-ve).

Answer:

1 Anomalous Pairs. The rest of the  pairs of elements don't follow the follow Mendeleev's Principles . they are :

2Grouping of chemically dissimilar elements.  

3Position of Isotopes.  

4Electronic arrangement.  

5Separation of chemically similar elements.  

6The position of hydrogen.

Explanation:

an acid will give away a proton and become a conjugate base.

A base will accept a proton and become a conjugate acid.

Answer:

The answer is "670.176 km".

Explanation:

Volume of the occupies of one  M & M= 0.5 \ cm^3\\\\

M&M 1 mole[tex]= 6.02 \times 10^{23}\\\\[/tex]

Calculating volume of M& M mole[tex]= 0.5 \ cm^3 \times 6.02 \times 10^{23}=3.01 \times 10^{23}\ cm^3\\\\[/tex]

Calculating the cube mole[tex]L^3= 3.01 \times 10^{23}\ cm^3\\\\[/tex]

[tex]L=6.70176 \times 10^{7}\ cm\\\\[/tex]

   [tex]=6.70176 \times 10^{7}\ cm \times \frac{1\ m}{100\ cm}\\\\=670176\ m\\\\=670.176 \ km[/tex]

Therefore 18 tractor trailers wouldn't be sufficient.

Answer:

bonding molecular orbital is lower in energy

antibonding molecular orbital is higher in energy

Explanation:

Electrons in bonding molecular orbitals help to hold the positively charged nuclei together, and they are always lower in energy than the original atomic orbitals.

Electrons in antibonding molecular orbitals are primarily located outside the internuclear region, leading to increased repulsions between the positively charged nuclei. They are always higher in energy than the parent atomic orbitals.

Answer:

12 g

Explanation:

From the question given above, the following data were:

Number of atoms = 6.02×10²³ atoms

Mass of ₆C¹² =?

From Avogadro's hypothesis,

1 mole of any substance contains 6.02×10²³ atoms. This implies that 1 mole of ₆C¹² also contains 6.02×10²³ atoms i.e

1 mole of ₆C¹² = 6.02×10²³ atoms

Recall

From the period,

1 mole of ₆C¹² = 12 g

Thus,

12 g of ₆C¹² = 6.02×10²³ atoms

Therefore, 12 g of ₆C¹² contains 6.02×10²³ atoms

Answer:

82 °C

Explanation:

Let the specific heat capacity of the coffee be that of water which is 4.2 J/g °C.

Now, at the final temperature, heat gained by Aluminum spoon ,Q equals heat lost by coffee, Q'.

Q = -Q'

Q = m₁c₁(T₂ - T₁) where m₁ = mass of aluminum spoon = 45 g, c₁ = specific heat of aluminum = 0.88 J/g °C, T₁ = initial temperature of aluminum spoon = 24 °C and T₂ = final temperature of aluminum spoon.

Q' = m₂c₂(T₂ - T₃) where m₂ = mass of coffee = 180 g, c₂ = specific heat of coffee = 4.2 J/g °C, T₃ = initial temperature of coffee = 85 °C and T₂ = final temperature of coffee.

So, Q = -Q'

m₁c₁(T₂ - T₁) = -m₂c₂(T₂ - T₃)

Making T₂ subject of the formula, we have

m₁c₁T₂ - m₁c₁T₁ = -m₂c₂T₂ + m₂c₂T₃

m₁c₁T₂ + m₂c₂T₂ =  m₂c₂T₃ + m₁c₁T₁

(m₁c₁ + m₂c₂)T₂ =  m₂c₂T₃ + m₁c₁T₁

T₂ =  (m₂c₂T₃ + m₁c₁T₁)/(m₁c₁ + m₂c₂)

substituting the values of the variables into the equation, we have

T₂ =  (180 g × 4.2 J/g °C × 85 °C + 45 g × 0.88 J/g °C × 24 °C )/(45 g × 0.88 J/g °C  + 180 g × 4.2 J/g °C)

T₂ =  (64260 J + 950.4 J)/(39.6 J/°C  + 756 J/°C)

T₂ =  65210.4 J/795.6 J/°C

T₂ =  81.96 °C

T₂ ≅  82 °C

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[tex]\pmb{\red{\boxed{\sf{Na_{2}O(s)+H_{2}O(l)\dashrightarrow 2NaOH(aq)   }}}}[/tex]

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D. the pupil or the dark portion at the center of the eye

Explanation:

here's the answer to your question

Answer:

A

Explanation:

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

I hope this helps

Answer: The given amount of [tex]Cd(NO_3)_2.4H_2O[/tex] contains 0.430 moles of Cd, 0.860 moles of N and [tex]2.59\times 10^{23}[/tex] molecules of water.

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of [tex]Cd(NO_3)_2.4H_2O[/tex] = 132.4 g

Molar mass of [tex]Cd(NO_3)_2.4H_2O[/tex] = 308.5 g/mol

Plugging values in equation 1:

[tex]\text{Moles of }Cd(NO_3)_2.4H_2O=\frac{132.4g}{308.5g/mol}=0.430 mol[/tex]

1 mole of [tex]Cd(NO_3)_2.4H_2O[/tex] contains 1 mole of Cd, 2 moles of nitrogen atom (N), 10 moles of oxygen atom (O) and 8 moles of hydrogen atom (H).

So, 0.430 moles of [tex]Cd(NO_3)_2.4H_2O[/tex] will contain = [tex](1\times 0.430) = 0.430mol[/tex] of Cd and [tex](2\times 0.430)=0.86mol[/tex] of N

According to the mole concept:

1 mole of a compound contains [tex]6.022\times 10^{23}[/tex] number of molecules

So, 0.430 moles of [tex]Cd(NO_3)_2.4H_2O[/tex] will contain = [tex]\frac{6.022\times 10^{23}}{1mol}\times 0.430mol=2.59\times 10^{23}[/tex] number of water molecules.

Hence, the given amount of [tex]Cd(NO_3)_2.4H_2O[/tex] contains 0.430 moles of Cd, 0.860 moles of N and [tex]2.59\times 10^{23}[/tex] molecules of water.

A. Coal

Others are animal remains

The fossil fuel which is the remains of ancient plants is: A. Coal.

Non-renewable energy can be defined as a type of energy that is mainly generated through artificial sources or from the remains of ancient plants.

Hence, a non-renewable energy cannot be replenished or renewed like the renewable energy sources.

Basically, some examples of a non-renewable energy include:

Coal deposits are typically petrified peat swamps and peat is generated from decaying plants.

Also, coal has been discovered to be a fossil fuel that contain the remains of ancient plants, based on radioactive dating.

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