Which of these is an example of a chemical change?

Answer:

porous = allowing liquid or air to pass through slowly

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Answer:

It is a rock or or other materials, having minutes interstices through which liquid or air may pass.

Answer:

Isotopes

Explanation:

An isotope are the atoms of an element with similar chemical identity and number of protons but different atomic masses. This means that isotopes of an element differ from one another by their number of NEUTRONS.

For example, the uranium element possesses isotopes as follows: Uranium-235 and uranium-238. This two isotopes have the same chemical identity and number of protons/atomic no., which is 92. However, the atomic masses (235 and 238) are different.

Answer:

Isotopes

Explanation:

ANSWER

2Ba + 2HBr → 2BaBr + H2

2BiCl3 + 3H2S → Bi2S3 + 6HCl

Br2 + 2KI → I2 + 2KBr

4Fe + 3O2 → 2Fe2O3

Answer:

[tex]3Mg _{(s)} + N _{2(g)} → Mg_{3} N _{2(s)}[/tex]

[tex]Ba _{(s)} + 2HBr_{(g)} → BaBr _{2(s)} + H _{2(g)}[/tex]

[tex]2BiCl_{3(s)} + 3H_{2} S _{(g)} → Bi _{2} S _{ 3(g)} + 6HCl _{(g)} \\ [/tex]

[tex]Br_{2(g)} + 2KI _{(g)} → I _{2(g)} +2 KBr _{(g)}[/tex]

[tex]4Fe_{(s)}+ 3O_{2(g)} → 2Fe_{2} O _{3(s)} [/tex]

Answer:

protons has a positive charge.

Neutrons does not have a charge (neutron = neutral)

Electrons has a negative charge

Answer:

The equilibrium shifts right to produce more SO3 molecules.

Explanation:

The equilibrium law states that when a system encounters a disturbance like a temperature, concentration, or pressure modifications, it will react to restore a new state of equilibrium.  

Adding a reactant such as oxygen (O2) will shift the reaction in the direction of the product, on the basis of the equilibrium law. Therefore, the equilibrium will move toward the product side.

Answer:

Chlorine

Explanation:

the ionization increases as you get closer to the top right. since chlorine (Cl) is the only one of the answer choices that is closer to the top right corner compared to phosphorous (P), that is the answer.

Answer:

cl

Explanation:

because ionization energy decrease from left to right

Explanation:

For example, elephants form groups with only females and their offspring. Once the male offspring reach a certain age, they leave the group and become solitary. Which is a benefit of this type of social group structure? A:Females do not have to compete for a mate.

when ph decrease that means acidity increase

when ph increase that means basicity increase

Answer:

Pour the sugar/diamond mixture into a container of water and stir until the sugar is dissolved completely. Then strain the mixture and wash the diamonds with water.

Answer:

Stir with a large enough volume of cold water to dissolve all the sugar. Filter to leave the diamonds on the filter paper. Wash on the filter paper with more water to remove any last traces of sugar solution. Allow to dry.

Answer:

4.48×10⁶ dm³

Explanation:

We'll begin by converting 23.4 tonnes to grams (g). This can be obtained as follow:

1 tonne = 10⁶ g

Therefore,

23.4 tonnes = 23.4 × 10⁶

23.4 tonnes = 2.34×10⁷ g

Thus, 23.4 tonnes is equivalent to 2.34×10⁷ g

Next, we shall determine the number of mole in 2.34×10⁷ g of NaCl. This can be obtained as follow:

Mass NaCl = 2.34×10⁷ g

Molar mass of NaCl = 58.5 g/mol

Mole of NaCl =?

Mole = mass / molar mass

Mole of NaCl = 2.34×10⁷ / 58.5

Mole of NaCl = 4×10⁵ moles

Next, we shall determine the number of mole of chlorine, Cl₂ produced from the reaction. This can be obtained as follow:

2NaCl —> 2Na + Cl₂

From the balanced equation above,

2 moles of NaCl reacted to produce 1 mole of Cl₂.

Therefore, 4×10⁵ moles of NaCl will react to produce = (4×10⁵ × 1)/2 = 2×10⁵ moles of Cl₂.

Thus, 2×10⁵ moles of Cl₂ were obtained from the reaction.

Finally, we shall determine the volume of Cl₂ produced. This can be obtained as follow:

1 mole of Cl₂ at stp = 22.4 dm³

Therefore,

2×10⁵ moles of Cl₂ at stp = 2×10⁵ 22.4

2×10⁵ moles of Cl₂ at stp = 4.48×10⁶ dm³

Thus, the volume of chlorine obtained from the reaction is 4.48×10⁶ dm³

Answer:

The answer is B. A hydrogen atom forms a convalent bond.........

Answer:

Option a is a solution acidic ([OH⁻] = 7.0x10⁻⁹ M).

Explanation:

To know if a solution is acidic we need to calculate the pH and it must be lower than 7. A value of pH equal to 7 is a neutral solution and a solution with a pH value higher than 7 is a basic solution.

a. For the [OH⁻] = 7.0x10⁻⁹ M we have:

[tex] pOH = -log[OH^{-}] = -log(7.0 \cdot 10^{-9}) = 8.15 [/tex]

Now, the pH is:

[tex] pH + pOH = 14 [/tex]

[tex] pH = 14 - pOH = 14 - 8.15 = 5.85 [/tex]

This solution is acidic (pH < 7)

b. [H₃O⁺] = 8.5x10⁻⁸ M

[tex] pH = -log(8.5 \cdot 10^{-8}) = 7.07 [/tex]

This is not an acidic solution. Is a neutral one (pH around to 7).

c. [OH⁻] = 2.5x10⁻⁶ M

[tex] pOH = -log[OH^{-}] = -log(2.5 \cdot 10^{-6}) = 5.60 [/tex]

Then, the pH is:

[tex]pH = 14 - pOH = 14 - 5.60 = 8.40[/tex]

Hence, this is not an acidic solution. It is basic (pH > 7).    

Therefore, option a is a solution acidic ([OH⁻] = 7.0x10⁻⁹ M).

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Answer:

Explanation:

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Answer:

B. they emit particles electromagnetic radiation or both

Radioactive isotopes emit particles, electromagnetic radiation, or both. The correct option is B.

Radioactive decay occurs in all radioactive isotopes and involves the release of particles, electromagnetic radiation, or both.

Radioactive decay occurs owing to the instability of the isotope's atomic nucleus.

The nucleus releases surplus energy in the form of particles (such as alpha particles or beta particles) or electromagnetic radiation (such as gamma rays) in order to achieve a more stable state.

This random process continues until the radioactive isotope is converted into a stable isotope.

Thus, correct option is B.

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Answer:

Explanation:

Potassium (K) atom has 19 electrons. The full electron configuration of Potassium (K) is 1s22s22p63s23p64s1

Principal energy level

Quantum number: n

1

2

3

4

5

6

Sublevels

availableQuantum number: l

1s

2s 2p

3s 3p 3d

4s 4p 4d 4f

5s 5p 5d 5f 5g

6s 6p 6d 6f 6g 6h

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Answer:

second (S) is the SI unit of time.

Answer:

second

Explanation:

the gap between any two intervals is called time

time can be measured in hour,minute,second

but second is the SI unit of time

Answer:

See explanation

Explanation:

Energy of the photon;

E = hc/λ

h= Planks constant

c= speed of light

λ = wavelength

E= 6.6 × 10^-34 × 3 × 10^8/4 x10 -7

E = 4.95 × 10^-19 J

If 1ev=1.602x10-19 J

x = 4.95 × 10^-19 J

x= 3.1 ev

From Einstein's photoelectric equation;

KE = E - Wo

Where;

KE = kinetic energy of ejected photoelectron

E= energy of the photon

Wo= work function of the metal

KE = 3.1 eV - 2.13 eV

KE= 0.97 eV

KE = 0.97 eV × 1.602x10-19 J

KE = 1.55 × 10^-19 J

KE = 1/2 mv^2

1.55 × 10^-19= 1/2 × 9.1 × 10^-31 × v^2

v= √2 × 1.55 × 10^-19/9.1 × 10^-31

v= 5.8 × 10^5 m/s

Answer:

Be,Mg,Ra etc

Explanation:

It should be palced in group 2A because as it reacts with chlorine in ratio of 1:2 . It's valancy is 2 and is metal as it react with non metal donating two electrons .

one more thing it fits there orderly

Answer:

D. the solvent particles to be spread further out and have more to move, increasing their kinetic energy.

Explanation:

Answer:

reduce the temperature of the gas

Explanation:

when you reduce the temperature of the gas the pressure will decrease

Answer:

Distillation:

Distillation is the process in which two or more liquids are separated on the basis of their boiling points.

Process:

Liquid mixture is heated. The liquid which is of low boiling point evaporates first and is condensed separately. This is followed by the liquid having more boiling point than the previous one and so on.

Reason:

A mixture of liquids having almost same boiling points cannot be separated. This is because both the liquids will evaporate at almost the same time when heated and thus, we will obtain the same liquid mixture again. No separation will occur.

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Answer:

Answer:

e.

6.7

hope it help

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Answer:

Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. All of the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are located in the cytoplasm.

Answer:

Explanation:

                             Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. All of the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are located in the cytoplasm. ...

Answer:

As water on the surface of lakes, oceans, and rivers warms up, it travels into the sky as very tiny droplets, or vapor. When the water vapor gets colder, it turns back to liquid to help form clouds.

When the liquid gets so heavy it can’t stay in the atmosphere anymore, it falls, or “precipitates,” as rain, snow, sleet, hail, or, my favorite, graupel. Once the precipitation reaches the ground or lands in lakes, oceans, and rivers, the cycle continues.

Explanation:

A scientist claims that the water molecules that you drink today could be millions of years old in the water cycle the new clouds athat re made cannot rain but the clouds which are old do rain.

The water cycle or cycle of water is the journey of each and every water molecule by which it is made up of as the clouds in the environment are made up of the evaporation process in the environment.

The vapors of evaporation condense in the environment to form the clouds and these clouds are only responsible for the rain but the old and heavy clouds can only do it.

Therefore, in the water cycle, the new clouds are made cannot rain but the clouds which are old do rain scientist claim that the water molecules that you drink today could be millions of years old.

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Answer:

8 mol

Explanation:

Step 1: Calculate the mass of PtCl₄ in the sample

10.00 grams of a sample of hydrated PtCl₄ are heated and lose 3.00 g of water. The mass of PtCl₄ is:

mPtCl₄ = 10.00 g - 3.00 g = 7.00 g

Step 2: Calculate the moles corresponding to 7.00 g of PtCl₄ and 3.00 g of H₂O

The molar mass of PtCl₄ is 336.9 g/mol.

7.00 g × 1 mol/336.9 g = 0.0208 mol

The molar mass of H₂O is 18.02 g/mol.

3.00 g × 1 mol/18.02 g = 0.166 mol

The molar ratio of H₂O to PtCl₄ is:

0.166 mol H₂O/0.0208 mol PtCl₄ ≈ 8 mol H₂O/ 1 mol PtCl₄

Answer:

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