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3 years ago

PLEASE. Arrange from highest to lowest highest melting point; NaCl, MgO, KBr, RbI. Explain your rationale.

Chemistry

1 answer:

Dmitry [639]3 years ago

8 0

Answer:

MgO> NaCl > KBr >RbI

Explanation:

Lattice energy refers to a measure of the energy contained in the crystal lattice of a compound. It is equal to the energy that would be released if the component ions were brought together from infinity. It is also defined as a measure of the energy released when ions are combined to make a compound or a measure of the cohesive forces that bind ions together in an ionic solid.

Melting points of ionic substances depend on their relative lattice energies. Similarly, the lattice energy depends on the size of the ions in the ionic solid. The smaller the sizes of the component ions, the greater the lattice energy. It can be seen that the sizes of cations and anions decrease steadily from RbI to MgO hence the lattice energy and melting point of the ionic solids increases in the order shown in the answer. The smaller the component ions in the lattice the greater the melting point of that ionic solid.

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What is meant by the term chemical reaction

pantera1 [17]

Answer:

<h3> $\huge{ \underline{ \underline { \bold{ \sf{ \orange{See \: below}}}}}}$ </h3>

Explanation:

▪️ $\underline{ \bold{ \sf{ \blue{Chemical \: reaction}}}}$

⇒The composition , decomposition or displacement of molecules of matter during chemical change is called chemical reaction.

▪️ $\underline{ \bold{ \sf{ \purple{ \: Further \: more \: explanation}}}}$

Various conditions bring about these changes. The chemical reactions are represented by chemicalequation. The compounds or elements that take part in chemical reaction are called reactant. They are written at the left side of an arrow that represent a change while the compound or elements that formed after the chemical change are called product. They are written at the right side of the arrow.

▪️ $\underline{ \bold{ \sf{ \purple{For \: example}}}}$

When nitrogen reacts with hydrogen to form ammonia :

Nitrogen + Hydrogen ⇒ Ammonia

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Hope I helped!

Best regards!!

3 0

2 years ago

What’s the answer for #9

zheka24 [161]

Freezer and refrigerator--> Too cold for most bacteria to grow (reproduce). Oven --> too hot for bacteria to survive

4 0

2 years ago

A sucrose solution is prepared to a final concentration of 0.250 M . Convert this value into terms of g/L, molality, and mass %.

MArishka [77]

Answer:

A. 85.6 g

= 0.0856 kg.

B. 0.00027 mol/g

= 0.27 mol/kg.

C. 8.39 %

Explanation:

Given:

Molar concentration = 0.25 M

Molar weight of sucrose = 342.296 g/mol

Density of solution = 1.02 g/mL

Mass of water = 934.4 g.

Density in g/l = 1.020 g/ml * 1000ml/1 l

= 1020 g/l

Mass of solution in 1 l of solution = 1020 g

Mass of solution = mass of solvent + mass of solute

Mass of sucrose = 1020 - 934.4

= 85.6 g of sucrose in 1 l of solution.

Density of sucrose = mass/volume

= molar mass/molar concentration

= 342.296 * 0.25

= 85.6 g/l

Number of moles = mass/molar mass

= 85.6/342.296

= 0.25 mol

Molality = number of moles of solute/mass of solvent

= 0.25/934.4

= 0.00027 mol/g

% mass of sucrose = mass of sucrose/total mass of solution * 100

= 85.6/1020 * 100

= 8.39 %

6 0

2 years ago

What type of radiation is emitted when chromium-51 decays into manganese-51? Show the nuclear equation that leads you to this an

Anastasy [175]

It's a beta decay
24Cr51 --> 25Mn51 + -1eo

4 0

3 years ago

Read 2 more answers

What expression approximates the volume of O2 consumed, measure at STP, when 55 g of Al reacts completely with excess O2?2 Al(s)

nikdorinn [45]

Answer : The volume of $O_2$ consumed are, $0.75\times 2\times 22.4$ L.

Explanation :

The balanced chemical reaction will be:

$4Al(s)+3O_2(g)\rightarrow 2Al_2O_3(s)$

First we have to calculate the moles of Al.

$\text{Moles of }Al=\frac{\text{Mass of }Al}{\text{Molar mass of }Al}$

Molar mass of Al = 27 g/mole

$\text{Moles of }Al=\frac{55g}{27g/mol}=2mole$

Now we have to calculate the moles of $O_2$ .

From the reaction we conclude that,

As, 4 mole of Al react with 3 moles of $O_2$

So, 2 mole of Al react with $\frac{3}{4}\times 2=0.75\times 2$ moles of $O_2$

Now we have to calculate the volume of $O_2$ consumed.

As we know that, 1 mole of substance occupies 22.4 liter volume of gas.

As, 1 mole of $O_2$ occupies 22.4 liter volume of $O_2$ gas

So, $0.75\times 2$ mole of $O_2$ occupies $0.75\times 2\times 22.4$ liter volume of $O_2$ gas

Therefore, the volume of $O_2$ consumed are, $0.75\times 2\times 22.4$ L.

3 0

3 years ago