How nephthalene can be purified by sublimation

Answer:

the valency of an element is its combining capacity that is the number of electrons it requires to lose, gain or share in order to become neutral.

[ An element can become neutral if it completes it's octet. That is if an element has 8 electrons in it'd outermost shell then it is considered neutral ]

Hence they both have the same valence.

One may say that oxygen's valence is -2 while that of Magnesium is + 2. It's meaning is still the same but "-" sign indicates that oxygen will be gaining electrons in the process of becoming stable.

Answer:

Gravity, Isaac Newton discover

The electron affinity is the energy required to remove an electron from an atom to yield a negative ion.

We know that atomic size increases down the group as more shells are added. This is because, inter-electronic repulsion pushes the electrons in the outermost shell farther away from the nucleus. Hence potassium atom has a larger atomic radius than a sodium atom because It has more energy levels occupied by electrons.

Electron affinity increases across the period. The more nonmetallic an element is, the more negative its electron affinity. Hence, sulfur has the greatest electron affinity.

Electron affinity is the opposite of ionization energy. It therefore follows that, the electron affinity of fluorine is essentially equal to the negative of the ionization energy F.

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Answer:

What is the question needing to be answered?

Explanation:

Usually with a scientific hypothesis, you ask the question in an if, then statement. For example: If it rains outside, then the ground will be wet. It's kind of like a cause and effect statement.

Answer:

we will solve your Quiz

Explanation:

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Answer:

SnO2(aq) + 2H2(g) → Sn(s) + 2H2O(g) - Redox reaction

AgNO3(aq) + KI(aq) → AgI(s) + KNO3(aq) - double replacement reaction

2Fe(s) + 3Br2(l) → 2FeBr3(s) - Formation

3H2SO4(aq) + 2Fe(s) → Fe2(SO4)3(aq) + 3H2(g) - Single replacement

2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) - Hydrocarbon combustion

4Al(s) + 3O2(g) → 2Al2O3(s) - Formation

2KI(l) → 2K(s) + I2(s) - Decomposition

3CaCl2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaCl(aq) - Double replacement

Explanation:

In an oxidation - reduction reaction, the oxidation number of the species involved in the reaction changes from left to right. One specie is oxidized while the other is reduced. E.g in SnO2(aq) + 2H2(g) → Sn(s) + 2H2O(g) - Sn^2+ was reduced while H2 was oxidized.

For a single replacement reaction, one specie is replaced in the reaction e.g H^+ is replaced by Fe^2+ in the reaction, 3H2SO4(aq) + 2Fe(s) → Fe2(SO4)3(aq) + 3H2(g) .

In a double replacement reaction, the ions on the reactant side exchange partners at the product side e.g 3CaCl2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaCl(aq)

In a formation reaction, two reactants combine to form a product. E.g 2Fe(s) + 3Br2(l) → 2FeBr3(s)

In a decomposition reaction, a compound breaks down to yield its components e.g 2KI(l) → 2K(s) + I2(s)

Hydrocarbon combustion refers to the reaction of a hydrocarbon compound with oxygen e.g 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g)

Answer:

B or C think so

Answer:

The number of hydrogen atoms is 4.96x10²⁴.

Explanation:

The number of atoms can be found with the following equation:

[tex] n = N*\eta_{H} [/tex]

Where:

N: is the Avogadro's number = 6.022x10²³ atoms/mol

η: is the number of moles of hydrogen

n: is the number of hydrogen atoms

First, we need to find the number of hydrogen moles. The number of moles of CH₄ is:

[tex] \eta_{CH_{4}} = \frac{m}{M} [/tex]

Where:

m: is the mass of methane = 33 g

M: is the molar mass of methane = 16.04 g/mol                      

[tex] \eta_{CH_{4}} = \frac{33 g}{16.04 g/mol} = 2.06 mol [/tex]

Now, since we have 4 hydrogen atoms in 1 mol of methane, the number of moles of hydrogen is:

[tex] \eta_{H} = 2.06\: mol\: CH_{4}*4 \frac{mol\: H}{mol \: CH_{4}} = 8.24 mol [/tex]

Hence, the number of hydrogen atoms is:

[tex]n = N*\eta_{H} = 6.022 \cdot 10^{23} \: atoms/mol*8.24 mol = 4.96 \cdot 10^{24} atoms[/tex]

Therefore, the number of hydrogen atoms is 4.96x10²⁴.

I hope it helps you!      

Answer: the atomic size will decrease

Explanation:

Answer:

It will remain the same because it is moving up and down to and fro it can not increase nor decrease or else will become an ion

Answer:

1.89 × 10^-11 M

Explanation:

Recall that;

[H^+] [OH^-] = 1 × 10^-14

[H^+] = concentration of hydronium ions

[OH^-] = concentration of hydroxide ion

Where [OH^-] = 5.3 × 10−4 M

[H^+]= 1 × 10^-14/5.3 × 10−4

[H^+]= 1.89 × 10^-11 M

Milk of magnesia, with a concentration of hydroxide ions of 5.3 × 10⁻⁴ M, has a concentration of hydronium ions of 1.9 × 10⁻¹¹ M.

Milk of magnesia (Mg(OH)₂) is an antacid, in which the concentration of hydroxide ions is 5.3 × 10⁻⁴ M.

We can calculate the concentration of hydronium ions at 25°C using the following expression.

[tex][H_3O^{+} ][OH^{-} ] = Kw = 1.0 \times 10^{-14} \\\\[H_3O^{+} ] = \frac{1.0 \times 10^{-14} }{[OH^{-} ]} = \frac{1.0 \times 10^{-14} }{5.3 \times 10^{-4} } = 1.9 \times 10^{-11} M[/tex]

where,

Since [H₃O⁺] < 10⁻⁷ M, the milk of magnesia is basic.

Milk of magnesia, with a concentration of hydroxide ions of 5.3 × 10⁻⁴ M, has a concentration of hydronium ions of 1.9 × 10⁻¹¹ M.

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a. Magnesium Burns in oxygen.

--⟩it produces light bright enough to blind you temporarily.

b. Calcium carbonate is heated.

--⟩ form calcium oxide and evolve carbon dioxide gas.

c. Hydrogen reacts with nitrogen at necessary condition.

----⟩some of the hydrogen and nitrogen will react to form ammonia.

d. potassium hydroxide reacts with nitric acid.

---⟩When potassium reacts with nitric acid then, potassium displace hydrogen from its solution and becomes colorless liquid.

e. Carbon dioxide is treated with limewater.

---⟩to form a white precipitate (appears milky) of calcium carbonate, CaCO 3.

Hope it is helpful to you

Answer:

Under regional metamorphism, metamorphic rocks are formed as a result of transformation of large areas of previously existing rocks under the influence of a large amount of heat and pressure which are created by tectonic forces.

Explanation:

Metamorphism is the phenomenon in the formation of metamorphic rocks whereby rocks are changed by heat and pressure. Now, during this process called metamorphism, rocks are bound to change either physically and chemically into a new rock. Now, there are two types of metamorphism namely;

Contact metamorphism and regional metamorphism.

We are concerned with regional metamorphism and it is defined as metamorphic rocks formed as a result of transformation of large areas of previously existing rocks under the influence of a large amount of heat and pressure which are created by tectonic forces.

Answer: yes

Explanation:

bilayer of lipids, oily substances found in all cells

Answer:

Explanation: Using the idea of Dobereiner's triads, what conclusion could have been made about magnesium,

had beryllium and calcium already been discovered?

Answer:

ds

Explanation:

sds

Answer:

the answer is known as 210°c

Answer:

Avogadro's number is the number of particles in one mole of anything. In this context, it is the number of atoms in one mole of an element. It's easy to find the mass of a single atom using Avogadro's number. Simply divide the relative atomic mass of the element by Avogadro's number to get the answer in grams.

Answer:

D. It is the same as the element's atomic mass, but in grams.

Explanation:

other answer didn't give the actual option lol

Answer:

Birds are able to sit on electrical power lines because the electrical current essentially ignores the bird's presence and continues to travel through the wire instead of through the bird's body. A bird's body is not a good conductor of electricity.

hope i helped

Answer:

phloem I believe

Explanation:

dictionary

When heating up, the balloon slowly rises and flies up in the air again. Explanation: The volume of the balloon decreases by the low temperature, because the gas inside is cooled down. When heated up, the pressure in the balloon rises, the balloon expands, and will reach to its original shape.

Believe it!!

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Answer:

freezing

Explanation:

because condensation is gas to liquid boiling is liquid to gas and sublimation is solid to gas

Answer:

yes it does

Explanation:

because the ratios on the reactants and products are equal

The reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.

Yes, this reaction obeys the law of conservation of mass. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; it is only rearranged.

In the given reaction, we have 2 sodium atoms (Na) on the left side and 2 sodium atoms (Na) on the right side. Similarly, we have 2 chlorine molecules (Cl₂) on the left side and 2 chlorine atoms (Cl) on the right side. Therefore, the number of atoms of each element is balanced on both sides of the reaction.

Additionally, the total mass of the reactants (2Na + Cl₂) is equal to the total mass of the product (2NaCl). The coefficients in the balanced equation represent the stoichiometric ratios, ensuring that the mass is conserved.

Hence, the reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.

Learn more about law of conservation of mass from the link given below.

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Answer:

the answer is option B it is a proton acceptor

Answer:

Yes a chemical reaction is taking place.

Explanation:

There is a change in temperature along with bubbling. All signs of a chemical reaction.

Answer:

FOUR HYDROGEN ATOMS

Explanation:

Two C atoms, four H atoms, and two O atoms can also be arranged to form a methyl formate, which is used in manufacturing, as an insecticide, and for quick-drying finishes. Methyl formate molecules have one of the oxygen atoms between the two carbon atoms, differing from the arrangement in acetic acid molecules.

The Methylene group has 2 hydrogen. -CH2

Answer:

½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)

½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole

NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole

General Formulas and Concepts:

Thermochemistry

Explanation:

An endothermic reaction would have heat or energy gained in the final stage of the reaction.

This means that our enthalpy would be positive and heat/energy would be added as a reactant.

Out of all the answer choices, we see that only these have heat/energy added in the reactant side or the enthalpy being positive:

½N 2(g) + O 2(g) + 8.1 kcal → NO 2(g)

½N 2(g) + ½O 2(g) → NO(g), ΔH = +21.6 kcal/mole

NH 3(g) → ½N 2(g) + 3/2H 2(g), ΔH = +11.0 kcal/mole

Topic: AP Chemistry

Unit: Thermochemistry

Answer:

4.73 mol NH

Explanation:

What we're doing here is calculating basic mole-mole relationships, something that you'll be doing quite a bit!

The steps to solving mole-mole problems like this are

write the balanced chemical equation for the reaction (this is given)

divide the number of moles of the given known substance (3.55) by that substance's coefficient in the chemical equation (3)

multiply that number by the coefficient of the substance you're trying to find (4)

Using simple dimensional analysis, it looks like this:

Answer:

4.68 H2O is needed to make 3.12 moles of NH3

Explanation:

Using stoichiometry, we can convert Moles of NH3 into Moles of H20

since we're converting moles to moles, we take the given mole of NH3

3.12, and multiply it by the Mole ratio, which in this case is (H20/NH3) or (6/4)

so then: 3.12 * 6/4 = 4.68 mols of H2O

Answer:

NH4+

Explanation:

NH4+ is the acid and NH3 is the base, so NH4+ is the stronger acid.