which among the following pairs are not isotopes?​

Answer:

C) K

Explanation:

K has an electron configuration of 2.8.8.1

Answer:

Explanation:The equation for this is F = -GmM/R^2 where the minus sign says the force is attractive m is 10 kg, M is 20 kg and R is 5 meters. If you crunch the numbers you get an answer of:

Answer:

1) The percentage of oxygen in dry air is _______

C. 21

2) The composition of the Earth’s earliest atmosphere was different to that of the present atmosphere. Which of these gases was present in large amounts in the Earth’s earliest atmosphere?

B. CARBON DIOXIDE

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Answer: The percentage of oxygen in dry air is .  21

Explanation:  Ammonia gases was present in large amounts  in the easth7s earliest atmosphere

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Answer:

Then, at some point, these higher energy electrons give up their "extra" energy in the form of a photon of light, and fall back down to their original energy level.

Explanation:

When properly stimulated, electrons in these materials move from a lower level of energy up to a higher level of energy and occupy a different orbital.

Answer:

Explanation:

Indira point is the southern most point of India and is situated on great nicobar island in the nicobar island.

Answer:

Your Ans Is

(A) Indra point.

Answer: The statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.

Explanation:

A strong acid upon dissociation gives a weak conjugate base. This can also be said as stronger is the acid, weaker will be its conjugate base or vice-versa.

Hydrofluoric acid is a strong base as it dissociates completely when dissolved in water.

For example, [tex]HF \rightleftharpoons H^{+} + F^{-}[/tex]

The conjugate base is [tex]F^{-}[/tex] which is a weak base.

Acetic acid is a weak acid as it dissociates partially when dissolved in water. So, the conjugate base of acetic acid is a strong base.

[tex]CH_{3}COOH \rightarrow CH_{3}COO^{-} + H^{+}[/tex]

Thus, we can conclude that the statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.

Answer:

exactly 0.10071444308 mols or just 0.1 mols

Explanation:

converting 6.4 g of copper to moles is done by using it's Molar Mass we can find the Molar Mass by lookin at the periodic table or just googling it. In this case, copper's molar mass is 63.546g per Mole. so thats 6.4/63.546 = 0.015736631731344 moles of copper

Answer:

10 m

Explanation:

From the question given above, the following data were obtained:

Velocity (v) = 14 m/s

Acceleration due to gravity (g) = 9.8 m/s²

Height (h) =?

Next, we shall determine the energy. This can be obtained as follow:

Velocity (v) = 14 m/s

Kinetic Energy (KE) =?

KE = ½mv²

KE = ½ × m × 14²

KE = ½ × m × 196

KE = m × 98

Finally, we shall determine the height. This can be obtained as follow:

Kinetic energy (KE) = m × 98

Acceleration due to gravity (g) = 9.8 m/s²

Height (h) =?

Since the object is falling from a particular height,

Potential energy (PE) = kinetic energy (KE)

PE = mgh

KE = m × 98

m × 9.8 × h = m × 98

Divide both side by m × 9.8

h = m × 98 / m × 9.8

h = 10 m

Thus, the bottle was dropped from a height of 10 m

Answer: Revoke the driver's license for at least 12 months

Explanation:

Chemical tests are used in order to measure the amount of drugs or alcohol that is in the body of a person when the person was arrested. To do this, samples of the urine or blood of the person can be taken and the result will be used to know if the person was driving under the influence of alcohol or not.

If the person refuse a legal chemical test issued by a law enforcement officer, the Division of Motor Vehicles is required to revoke the the driver's license of the person for at least 12 months.

Answer:

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Answer:

C) H2PO4, HCO3, NH4Cl

Explanation:

Because all of the above compounds on reaction with water liberate H+ ion which is the identification of an acid acc to Arhenius Theory

Answer:

-0.75 , 1.25

Explanation:

Number of electrons present in valence shell,

P-O = 5 + 8 = 13

Number of electrons involved in bond formation,

13 - 3 = 10

Number of bonds in PO3 - 4ion = 102

Average P-O bond = 1.25

Average formal charge on Oxygen atom is -0.75

Answer:

A standard system of measurement is very important because it helps us from making mistakes at the moment of doing calculations and correctly working...

Answer:

A standard measurement system is important because it allows scientists to compare data and communicate with each other about their results. Metric System – is a measurement system based on the number 10.

Answer:

because they are high reactive to the air thats why we keep them in paroffin oil

Answer:

ΔH = -746.6kJ

Explanation:

Using Hess's law we can find the ΔH of a reaction from the sum of similar reactions. From the reactions:

1. 2CO(g) + O2(g) → 2CO2 ΔH = -566.0kJ

2. N2(g) + O2(g) → 2NO(g) ΔH = 180.6kJ

The negative reaction of 2:

-2. 2NO(g) → N2(g) + O2(g) ΔH = -180.6kJ

The sum of 1 - 2:

2CO(g) + O2(g) + 2NO(g) → 2CO2  N2(g) + O2(g) ΔH = -566.0kJ + (-180.6kJ) =

ΔH = -746.6kJ

Subtracting the molecules that don't change:

2CO(g) + 2NO(g) → 2CO2  + N2(g) ΔH = -746.6kJ

Answer:

The correct answer is - at high pressure a huge amount of gases can be stored in less volume.

Explanation:

We already know that pressure is inversely proportional to the volume of gas which means if we increase the pressure the volume of gas becomes less.

P = 1/V

So in the scuba divers tank, the oxygen is filled at very high pressure so the high amount of the oxygen can be filled in less volume and which will last for longer than a normal pressure tank can last.

An atom is neutral as it has the same number of electrons that of protons. So, if an atom has 32 protons i.e. the atomic number of it is 32, then it will have 32 electrons revolving the nucleus.

Answer:

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Answer:

D. Zn²⁺ + 2Ag → Zn + 2Ag⁺

Explanation:

On the reduction potential chart, we have that silver ion Ag⁺ is a stronger oxidizing agent than, zinc, Zn, which is a reducing reducing agent the compared to silver

Therefore, the redox reaction that will occur is that the zinc, Zn, will be oxidized to Zn²⁺ ion, while the silver, Ag²⁺ ion will be reduced to silver deposits Ag, therefore, the zinc will displace the silver in the solution containing silver and zinc ions because zinc is higher than silver in the reactivity series

The reduction potential Zn → Zn²⁺ + 2e⁻ = +0.76

The reduction potential for Ag⁺ + e⁻ → Ag = +0.8

Therefore, given that redox reactions are reversible, we get the following likely redux reaction;

Zn(s) + 2Ag⁺(aq) ⇄ 2Ag(s) + Zn²⁺(aq)

Therefore, from the given options;

Zn²⁺(aq) + 2Ag(s) → Zn(s) + 2Ag⁺(aq) is the reaction most likely to occur.

8g + 65g = 73g

24g + 38g = 62g

Answer:

1)Na + O2 = > 2NaO

8 g + 65 g = > 73g

2) 2H2 + O2 → 2H2O

24 g + 38g→ 62 g

Answer:

[tex]V=795.26L[/tex]

Explanation:

From the question we are told that:

Volume [tex]V=1dm^3=>1L[/tex]

Density [tex]\rho=70.8g/L[/tex]

Generally the equation for Density is mathematically given by

[tex]\rho =\frac{Mass}{Volume}[/tex]

Therefore

[tex]M=\rho*V[/tex]

[tex]M=70.8*1[/tex]

[tex]M=70.8g[/tex]

Since at STP

[tex]T=273K[/tex]

[tex]P=1atm[/tex]

[tex]Mass =70.8g[/tex]

Therefore

[tex]Moles\ of\ Hydrogen=\frac{Mass}{2g}[/tex]

[tex]Moles\ of\ Hydrogen=\frac{70.8}{2g}[/tex]

[tex]Moles\ of\ Hydrogen=35.4moles[/tex]

Generally the equation for Ideal gas is mathematically given by

[tex]PV=nRT[/tex]

Therefore

[tex]V=\frac{nRT}{P}[/tex]

[tex]V=\frac{35.4*0.0826*273}{1}[/tex]

[tex]V=795.3L[/tex]

Answer:

the last answer is right.

Answer:

51.6058

Explanation:

The percentage of abundance is changed to decimal by dividing 100

Answer:

130 mL

Explanation:

2FeCl3(aq) + 3K2S(aq) -----> Fe2S3(s) + 6KCl(aq)

Percent yield = actual yield/theoretical yield × 100

actual yield = 2.75 g

Theoretical yield = x

65= 2.75/x × 100

x= 2.75 × 100/65

x= 4.2 g

Number of moles of FeCl3 = mass/molar mass = 4.2 g/ 162.2 g/mol = 0.026 moles

Then;

n= CV

n= number of moles

C= concentration

V= volume

V= n/C

V= 0.026 moles/ 0.200 M

V= 0.13 L or 130 mL

1. Sodium triphosphate ·

2. Sodium hydroxide ·

3. potassium hydroxide

4. Sodium Lauryl Sulfate · 5.Hydroxyethylcellulose ·

6. Sodium carbonate

A magnesium ribbon is cleaned to remove the protective layer of basic magnesium carbonate from its surface, so that it may readily combine with the oxygen in air (on heating).

Answer:

Magnesium gets covered with a layer of magnesium oxide when kept in air for a long time. This layer hinders the burning of magnesium. Hence, it is to be cleaned before burning.

Answer: Decomposition is the answer

Explanation: why because aluminium hydroxide would decomposes in the presence of heat and would form an oxide which is aluminium oxide and would also form water as a product.

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