What are you most likely to observe when an endothermic reaction is taking place?

Answer:

Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P4) or sulfur (S8) cannot be broken down into simpler substances by these reactions.

Example: Water decomposes into a mixture of hydrogen and oxygen when an electric current is passed through the liquid. Hydrogen and oxygen, on the other hand, cannot be decomposed into simpler substances. They are therefore the elementary, or simplest, chemical substances - elements.

Each element is represented by a unique symbol. The notation for each element can be found on the periodic table of elements.

The elements can be divided into three categories that have characteristic properties: metals, nonmetals, and semimetals. Most elements are metals, which are found on the left and toward the bottom of the periodic table. A handful of nonmetals are clustered in the upper right corner of the periodic table. The semimetals can be found along the dividing line between the metals and the nonmetals.

Explanation:

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:

A system of measurement is a collection of units of measurement and rules relating them to each other. ... Systems of measurement in use include the International System of Units (SI), the modern form of the metric system, the British imperial system, and the United States customary system.

Explanation:

Hope it works!!!!

Answer:

Systems of measurement in use include the International System of Units (SI), the modern form of the metric system, the British imperial system, and the United States customary system.

Answer:

the reactants are carbon dioxide ,iron, oxygen

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:

B. decreases

Explanation:

The solubility of gases in a liquid is inversely proportional to the temperature, it means that if you increase the temperature, the solubility decreases.

Answer:

27.79 g to the nearest hundredth.

Explanation:

2Na + Cl2 ---> 2NaCl

Using the molar masses , the theoretical yield is:

46 g of Na yields  46 + 35.5*2 g NaCl

46 g ---> 117 g NaCl  so

11.5 g ----> 117 * 11.5 / 46 g NaCl

But, as the yield is 90%

the actual yield is 0.95 * 117 * 11.5 / 46

= 27.79 g.

Answer:

A

Explanation:

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

I hope this helps

Explanation:

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Answer: Newton's Third Law of Motion.

Explanation:

Newton's Third Law of Motion simply states that every action force creates a reaction force and then, this reaction force will be equal in strength and opposite in direction.

The statement simply implies that in every interaction, there will be a pair of forces that is acting on the two interacting objects. An example of Newton's third law of motion can be seen when a person jumps, thenlegs of the person will apply a force to the ground which will then propel the person into the air.

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:

BIOHEAT is a biodiesel mix that can be utilized (without equipment changes) in most home heaters. BIOHEAT promptly diminishes various hurtful discharges from heater use (up to 80% contingent upon blend used) and the oil is made from nearby feedstocks like utilized cooking oil

Answer: broooo what is this

Explanation:

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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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:

D. electron

Explanation:

Same molecular structure and same properties.

Molecular structure is three dimensional structure in which arrangement of atoms is placed.

The molecular structure of a compound determines the polarity and its reactivity.

The different states of matter solid, liquid and gas have different molecular structure and different properties from each other.

The molecular structure of a molecule will have same properties as of the entire molecule based on its state.

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Answer:

the location of atoms, groups, or ions relative to one another and the number, type, and location of covalent bonds

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]

Answer:

The electron from the ground state to occupy a next energy level. In this case,we say that the electron is excited

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.

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 could be wrong letter c

Answer:

Answer: Atoms of chlorine (CI) and magnesium (Mg)

Answer: Atoms of chlorine (CI) and magnesium (Mg)is your answer

Answer:

a. 1 x 10^-35

Explanation:

The correct compound given is: [tex]\mathsf{Cu_3(AsO_4)}_2[/tex]

To predict the approximate Ksp value of the given compound, we will need to express the oxidation-reduction half-reaction of the compound and its dissociation, then, we will use the Nernst equation to determine the approximate Ksp value.

To start with the reduction half-reaction:

[tex]\mathsf{Cu_3(AsO_4)_{2}(s) + 6e^- \to 2As O_{4}^{3-}_{(aq)}+3Cu(s) }[/tex]

The oxidation half-reaction is:

[tex]\mathsf{3Cu(s) \to 3CU^{2+}_{(aq)} + 6e^-}[/tex]

The overall cell reaction now is:

[tex]\mathsf{Cu_3(AsO_4)_{2}(s) \to 3Cu^+ (aq) + 2As O_{4}^{3-}_{(aq)} }[/tex]

From the reduction half-reduction, the number of moles of electrons (n) transferred is 6 moles.

By applying the Nernst equation:

[tex]\mathsf{E_{cell} = E^0_{cell} -\dfrac{0.0591V}{n}log [Cu^{2+}]^3[AsO_4^{3-}]^2 }[/tex]

At standard conditions;

The standard cell potential [tex]\mathsf{E^0_{cell} = -0.342 \ V}[/tex]

and [tex]\mathsf{E_{cell} = 0 \ V}[/tex] since it is at equilibrium.

∴

[tex]\mathsf{0 = -0.342 -\dfrac{0.0591V}{6}log [Cu^{2+}]^3[AsO_4^{3-}]^2 } \\ \\ \\ \mathsf{0.342 = -\dfrac{0.0591V}{6}log [Cu^{2+}]^3[AsO_4^{3-}]^2 }[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 = \dfrac{-(0.342)*6}{0.0591 }}[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 = -34.7}[/tex]

[tex]\mathsf{log [Cu^{2+}]^3[AsO_4^{3-}]^2 \simeq -35}[/tex]

[tex]\mathsf{[Cu^{2+}]^3[AsO_4^{3-}]^2 = 10^{-35}}[/tex]

[tex]\mathbf{K_{sp} = [Cu^{2+}]^3[AsO_4^{3-}]^2 = 1\times 10^{-35}}[/tex]

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:

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

Answer:

I can't understand your language? can you write in English

I'm sorry

Answer:

The answer is A: The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster.

Explanation:

Think about it, if you boil water, whatever you put in the water is going to move around faster than if you put something in standing water.

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The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster. The correct answer is A.

Food coloring, or color additive, is any dye, pigment, or substance that imparts color when it is added to food or drink.

The food coloring we add to the water is pushed around by the water molecules. Since the molecules in warm water move around faster, the food coloring spreads out quicker in warm water than in cold water.

From the table, we can say that the water in glass B was heated by Ted and the molecules of food coloring spread out quickly in warm water and they have greater kinetic energy and move faster.

On the other hand, in glass A, the water is cold, so food coloring will not dissolve quickly.

Therefore, The water in Glass B was heated; therefore, the particles in Glass B have greater kinetic energy and move faster. The correct answer is A.

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