A) 24 g
B) 36 g
C) 48 g
D) 60 g

Answer: It will take 9.13 minutes for the sample.

Explanation:

Expression for rate law for first order kinetics is given by:

[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]

where,

k = rate constant  

t = age of sample

a = initial amount of the reactant = [tex]2.81\times 10^4[/tex]

a - x = amount left after decay process = [tex]3.52\times 10^3[/tex]

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]

[tex]k=\frac{0.693}{3.05min}=0.227min^{-1}[/tex]

b) for activity to decrease from 2.81E4 Ci to 3.52E3 Ci:

[tex]t=\frac{2.303}{0.227}\log\frac{2.81\times 10^4}{3.52\times 10^3}[/tex]

[tex]t=9.13min[/tex]

Thus it will take 9.13 minutes for the sample.

[tex]t_{99.9}=40min[/tex]

The time after which 99.9% reactions gets completed is 40 minutes

Answer:

See explanation

Explanation:

Solvolysis is a chemical reaction in which the solvent, such as water or alcohol, is one of the reagents and is present in great excess of that required for the reaction.  The solvents act as or produce electron-rich atoms or groups of atoms (nucleophiles) that displace an atom or group in the substrate molecule(Encyclopedia Britannica).

For the two reactions, the organic product is the same(the product is drawn in the second image attached). The both reactions occur by SN1 mechanism since the substrate is a tertiary alkyl halide. The nucleophile is CH3OH and the rate of reaction depends on the concentration of the alkyl halide and independent of the concentration of methanol present.

Therefore, changing the volume of the solvent has no effect on the rate of reaction. The two reactions proceed at exactly the same rate since the initial concentration of the alkyl halide is the same for both reactions.

Explanation:

If a large photon strikes the surface, that has enough strength to take out an electrode, which will then travel to the positive side since it is negative. Current is flowing at this stage. Since the reduced photons will be unable to distinguish between atoms, no power can pass.

Answer:

Transition metals differ from the non-transition metals such as magnesium in the following ways;

Explanation:

Transition elements comprise of those elements in the d-block of the periodic table and which have incompletely-filled d-orbitals.

The transition elements are all metals and has the characteristic physical properties of metals such as;

However, their chemical properties differ from those of the non-transition metals such as magnesium in the following ways;

Answer:

carbon

Explanation:

Many organisms use carbon to make calcium carbonate, a building material of shells and skeletons. Other chemical processes create calcium carbonate in the water. The using up of carbon by biological and chemical processes allows more carbon dioxide to enter the water from the atmosphere.

Answer:

A. Energy is absorbed because the product has more energy than the reactants have.

Here the energy of both reactants is combined together and not released.

Answer:

Natural selection changes how well a species can survive in an environment.

Explanation:

I'm not the best at biology, but natural selection a term we use that's describes nature's way of choosing the strongest to survive. The species with the strongest adaptations will survive while the others will die off. For example, if a school of fish was forced to live in a colder habitat than usual, over many years some fish will adapt to that environment and be able to withstand it. But, some fish won't get those adaptations and be killed off. But, future generations will be born with that ability to withstand the cold environment and it would become normal. So, natural selection changes the way a species lives. Hope this helps

Answer:

3A     +     B      →     C      +      2D

Explanation:

Recall that:

[tex]\text{molarity} = \dfrac{no \ of \ moles}{volume \ of \ the \ solution}[/tex]

So;

[tex]\text{no \ of \ moles= molarity * volume \ of \ the \ solution}[/tex]

From the above table given in the question; we can have the following table:

Run            moles of A            moles of B     Limiting reagent

1                 0.5×  10⁻²                 0.5×  10⁻²           A and B are equal

2               1.0 0.5×  10⁻²             0.5×  10⁻²          A

3.               1.5×  10⁻²                   0.5×  10⁻²          A

4               2.0×  10⁻²                    0.5×  10⁻²         B

Also, provided that the stoichiometric coefficients for C and D = 1 & 2 respectively.

Then, the stiochiometric ratio for A:B = [tex]\dfrac{1.5\times 10^{-2}}{0.5 \times 10^{-2}}[/tex]

[tex]= \dfrac{3}{1}[/tex]

Thus, the balanced equation is:

3A     +     B      →     C      +      2D

Explanation:

the atmoc radius across the period

Answer:

Here

Explanation:

An invasive species is an organism that causes ecological or economic harm in a new environment where it is not native. ... Invasive species are capable of causing extinctions of native plants and animals, reducing biodiversity, competing with native organisms for limited resources, and altering habitats.

Answer:

0.1023 moles

Explanation:

We have this reaction

Na2HPO4 → 2Na+ + NPO4-

1 mole gives us 3 ions

Na+ has 2 ions to it

NPO4 has 1 ion

2 + 1 = 3

We multiply 3 with the number of moles to get the answer to this question

3 x 0.0341

= 0.1023 moles

So we conclude that total moles released when dissolved in water is equal to 0.1023

Answer:

The answer is "Choice A".

Explanation:

In this question, the choice A is wrong because when the copper panels on houses produce a patina (copper oxide) through occur as a consequence of reactions from oxygen and water in the air, these reaction does not have low activation energy because lower activation energy that is stored in a faster response rate.

Answer:

Follows are the solution to these question:

Explanation:

Given equation:

[tex]N_2+3H_2 \longrightarrow 2NH_3[/tex]

In this equation:

[tex]1 N_2[/tex] gives [tex]= 2NH_3[/tex]

so,

[tex]3N_2[/tex] gives=  [tex]2 \times 3 = 6 NH_3[/tex]

similarly:

[tex]3H_2[/tex] gives [tex]= 2NH_3[/tex]

So, [tex]6H_2[/tex] gives = [tex]\frac{2}{3}\times 6=4NH_3[/tex]

Its limited reagent is =[tex]N_2[/tex]

The amount of [tex]NH_3[/tex] molecules were formed = 4.

and the amount of  [tex]H_2[/tex] excess molecules are= 1

Answer:

Hope some of these give you impetus to think of other bullet points, sounds good to me.  !!

Explanation:

Answer:

A) Fission

Explanation:

Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy.

Answer:

Explanation:

Expression for capillary rise is as follows

h = 2T / ρ g r where T is surface tension , ρ is density of liquid and r is radius of capillary tube.

T = .032 J m⁻²

ρ = .71 g / cm³

= 7100 kg / m³

r = .1 x 10⁻³ m = 10⁻⁴ m

h = 2 x .032 / (7100 x 9.8 x 10⁻⁴ )

h = .0092 m

= 9.2 mm .

Answer:

A

Explanation:

if the earth slows down then that will give more time to the sun meaning days/nights will be longer

Answer:

hahahaa i can get the points

Explanation:

yes it is again LOL thanks

Answer:

Hydrogen fuel cells do not produce any CO2 emissions during operation, even if their production is not necessarily carbon-free. This gives them an advantage over combustion engine vehicles, which can emit small amounts of poisonous carbon monoxide and require well-ventilated rooms for indoor use.

Answer:

11.25 moles of O₂.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

C₃H₈ + 5O₂ —> 3CO₂ + 4H₂O

From the balanced equation above,

1 mole of C₃H₈ reacted with 5 moles of O₂.

Finally, we shall determine the number of mole of O₂ needed to react with 2.25 moles of C₃H₈. This can be obtained as follow:

From the balanced equation above,

1 mole of C₃H₈ reacted with 5 moles of O₂.

Therefore, 2.25 moles of C₃H₈ will react with = 2.25 × 5 = 11.25 moles of O₂.

Thus, 11.25 moles of O₂ is needed for the reaction.

Answer:

In thin-layer chromatography, the retention factor (Rf) is used to compare and help identify compounds. The Rf value of a compound is equal to the distance traveled by the compound divided by the distance traveled by the solvent front (both measured from the origin).

Answer:

C

Explanation:

The Law of Conservation of energy is that energy can be transformed from one form to another, but can be neither created or destroyed.

Answer:

hello your question is incomplete attached below is missing part

answer : Pauli's exclusion principle

Explanation:

The principle that was disobeyed is Pauli's exclusion principle this is because the  Pauli's exclusion principle states that no two electrons can have the same set of quantum number.

In Box A the two electrons , have the same spin which means  they have the same quantum number ( disobeys Pauli's exclusion principle )

Answer:

C6H12O2

Explanation:

The Jones reagent is a reagent in organic chemistry used to convert primary alcohols to carboxylic acids and secondary alcohols to ketones. Recall that tertiary alcohols can not be oxidized.

The compound  2-methyl-2,3-pentandiol contains one secondary and one tertiary alcohol. The secondary alcohol is oxidized to a ketone while the tertiary alcohol is not oxidized.

Hence the product of the oxidation using Jones reagent is 2-Hydroxy-2-methyl-3-pentanone with the molecular formula C6H12O2.

Answer:

sir/ma'am, i know i'm a NOOB at this kind of stuff but i believe it's oxygen.

Explanation:

i can't really remember the answer since it's been a week or so that i done this problem, it's between nitrogen and oxygen, though, i believe it's oxygen.

if ya don't believe me or trust me, then here's the link to help ya:

https://socratic.org/questions/what-elements-would-have-similar-properties-to-sulfur#628367

Answer:

B. hydrogen storage

Explanation:

Answer: B hydrogen storage

Explanation:

correct on edge 2020

Answer:

Explanation:

C defo

Answer: I can help with that!

Explanation: 1.The tremendous growth in the U.S. solar industry is helping to pave the way to a cleaner, more sustainable energy future. Over the past few years, the cost of a solar energy system has dropped significantly -- helping to give more American families and business access to affordable, clean energy.

Through a portfolio of R&D efforts, the Energy Department remains committed to leveraging America’s abundant solar energy resources -- driving research, manufacturing and market solutions to support widespread expansion of the nation’s solar market.

2.The amount of sunlight that strikes the earth's surface in an hour and a half is enough to handle the entire world's energy consumption for a full year. Solar technologies convert sunlight into electrical energy either through photovoltaic (PV) panels or through mirrors that concentrate solar radiation. This energy can be used to generate electricity or be stored in batteries or thermal storage.

Below, you can find resources and information on the basics of solar radiation, photovoltaic and concentrating solar-thermal power technologies, electrical grid systems integration, and the non-hardware aspects (soft costs) of solar energy. You can also learn more about how to go solar and the solar energy industry. In addition, you can dive deeper into solar energy and learn about how  the U.S. Department of Energy Solar Energy Technologies Office is driving innovative research and development in these areas.

3.Solar radiation is light – also known as electromagnetic radiation – that is emitted by the sun. While every location on Earth receives some sunlight over a year, the amount of solar radiation that reaches any one spot on the Earth’s surface varies. Solar technologies capture this radiation and turn it into useful forms of energy.

Answer:

25.88 g of F₂.

Explanation:

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

Number of molecules of F₂ = 4.10×10²³ molecules

Mass of F₂ =?

From Avogadro's hypothesis,

1 mole of F₂ = 6.02×10²³ molecules

Next, we shall determine the mass of 1 mole of F₂. This can be obtained as follow:

1 mole of F₂ = 2 × 19 = 38 g

Thus,

38 g of F₂ = 6.02×10²³ molecules

Finally, we shall determine the mass of 4.10×10²³ molecules of F₂. This can be obtained as follow:

6.02×10²³ molecules = 38 g of F₂

Therefore,

4.10×10²³ molecules = 4.10×10²³ × 38 / 6.02×10²³

4.10×10²³ molecules = 25.88 g

Thus, 25.88 g of F₂ contains 4.10×10²³ molecules.