0.5 g of salt is dissolved in 25 g of water. Calculate the percentage amount of salt in the solution.

Answer:

None of them, answer seems to be 24 unless I messed up

Explanation:

How many electrons appear in the balanced equation

What the heck do they mean, do they mean transferred?

N2O5 --> NH4+

Left Side

N 5+  Electrons 2 in central shell, 5 in outer

O 2- Electrons 2 in central shell, 6 in outer

Right Side

H  1+ Electrons 1 in central shell

N 3- Electrons 2 in central shell, 5 in outer

Hmm, ok so need to balance the half equation first, this is a redox reaction.

Hmm, so it's going to be something like

H2 + N2O5 → NH + O3  

Step 1. Write down the unbalanced equation ('skeleton equation') of the chemical reaction. All reactants and products must be known. For a better result write the reaction in ionic form.

H2 + N2O5 → NH + O3  

Step 2. Separate the process into half reactions. A redox reaction is nothing but both oxidation and reduction reactions taking place simultaneously.

a) Assign oxidation numbers for each atom in the equation. Oxidation number (also called oxidation state) is a measure of the degree of oxidation of an atom in a substance (see: Rules for assigning oxidation numbers).

H02 + N+52O-25 → N-1H+1 + O03  

b) Identify and write out all redox couples in reaction. Identify which reactants are being oxidized (the oxidation number increases when it reacts) and which are being reduced (the oxidation number goes down). Write down the transfer of electrons. Carefully, insert coefficients, if necessary, to make the numbers of oxidized and reduced atoms equal on the two sides of each redox couples.

When one member of the redox couple is oxygen with an oxidation state of -2 or hydrogen with an oxidation state of +1, it is best to replace it with a water molecule.

O:3H+12O-2 → O03 + 6e-(O)

H02 → H+12O-2 + 2e-(H)

R:N+52O-25 + 12e- → 2N-1H+1(N)

c) Combine these redox couples into two half-reactions: one for the oxidation, and one for the reduction (see: Divide the redox reaction into two half-reactions).

O:3H+12O-2 + H02 → O03 + H+12O-2 + 8e-  

R:N+52O-25 + 12e- → 2N-1H+1  

Step 3. Balance the atoms in each half reaction. A chemical equation must have the same number of atoms of each element on both sides of the equation. Add appropriate coefficients (stoichiometric coefficients) in front of the chemical formulas to balance the number of atoms. Never change any formulas.

a) Balance all other atoms except hydrogen and oxygen. We can use any of the species that appear in the skeleton equations for this purpose. Keep in mind that reactants should be added only to the left side of the equation and products to the right.

O:3H+12O-2 + H02 → O03 + H+12O-2 + 8e-  

R:N+52O-25 + 12e- → 2N-1H+1  

b) Balance the charge. For reactions in an acidic solution, balance the charge so that both sides have the same total charge by adding a H+ ion to the side deficient in positive charge.

O:3H+12O-2 + H02 → O03 + H+12O-2 + 8e- + 8H+  

R:N+52O-25 + 12e- + 12H+ → 2N-1H+1  

c) Balance the oxygen atoms. Check if there are the same numbers of oxygen atoms on the left and right side, if they aren't equilibrate these atoms by adding water molecules.

O:3H+12O-2 + H02 + H2O → O03 + H+12O-2 + 8e- + 8H+  

R:N+52O-25 + 12e- + 12H+ → 2N-1H+1 + 5H2O  

Balanced half-reactions are well tabulated in handbooks and on the web in a 'Tables of standard electrode potentials'. These tables, by convention, contain the half-cell potentials for reduction. To make the oxidation reaction, simply reverse the reduction reaction and change the sign on the E1/2 value.

Step 4. Make electron gain equivalent to electron lost. The electrons lost in the oxidation half-reaction must be equal the electrons gained in the reduction half-reaction. To make the two equal, multiply the coefficients of all species by integers producing the lowest common multiple between the half-reactions.

O:3H+12O-2 + H02 + H2O → O03 + H+12O-2 + 8e- + 8H+| *3

R:N+52O-25 + 12e- + 12H+ → 2N-1H+1 + 5H2O| *2

O:9H+12O-2 + 3H02 + 3H2O → 3O03 + 3H+12O-2 + 24e- + 24H+  

R:2N+52O-25 + 24e- + 24H+ → 4N-1H+1 + 10H2O  

Step 5. Add the half-reactions together. The two half-reactions can be combined just like two algebraic equations, with the arrow serving as the equals sign. Recombine the two half-reactions by adding all the reactants together on one side and all of the products together on the other side.

9H+12O-2 + 2N+52O-25 + 3H02 + 24e- + 3H2O + 24H+ → 3O03 + 4N-1H+1 + 13H2O + 24e- + 24H+

Step 6. Simplify the equation. The same species on opposite sides of the arrow can be canceled. Write the equation so that the coefficients are the smallest set of integers possible.

2N+52O-25 + 3H02 → 3O03 + 4N-1H+1 + H2O

Answer: thats alot of reading

Explanation:

Answer:

The two objects have the same electric charge.

Explanation:

Electrically charged objects repel if they are both of the same charge, ie plus plus or minus minus.

The statement, that describes two electrically charged objects repel one another is "the two objects have the same electric charge."

The feature of subatomic particles that causes them to experience a force when put in an electric and magnetic field is known as electric charge.

When one or more items are electrically charged, electrostatic interactions are widespread. Two items with opposing charges will attract each other.

Unlike the attractive force between two items with opposite charges, two objects with like charges repel each other. In other words, a positively charged object will repel another positively charged object. This repelling force will separate the two items.

Hence the correct answer is the two objects have the same electric charge.

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Answer : The value of [tex]\Delta H_{rxn}[/tex] for the reaction is, -390.3 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The main chemical reaction is:

[tex]CH_4(g)+4Cl_2(g)\rightarrow CCl_4(g)+4HCl(g)[/tex]    [tex]\Delta H_{rxn}=?[/tex]

The intermediate balanced chemical reaction are:

(1) [tex]C(s)+2H_2(g)\rightarrow CH_4(g)[/tex]     [tex]\Delta H_1=-74.6kJ[/tex]

(2) [tex]C(s)+2Cl_2(g)\rightarrow CCl_4(g)[/tex]     [tex]\Delta H_2=-95.7kJ[/tex]

(3) [tex]H_2(g)+Cl_2(g)\rightarrow 2HCl(g)[/tex]     [tex]\Delta H_2=-184.6kJ[/tex]

Now we are reversing reaction 1, multiplying reaction 3 by 2 and then adding all the equations, we get :

(1) [tex]CH_4(g)\rightarrow C(s)+2H_2(g)[/tex]     [tex]\Delta H_1=74.6kJ[/tex]

(2) [tex]C(s)+2Cl_2(g)\rightarrow CCl_4(g)[/tex]     [tex]\Delta H_2=-95.7kJ[/tex]

(3) [tex]2H_2(g)+2Cl_2(g)\rightarrow 4HCl(g)[/tex]     [tex]\Delta H_2=2\times (-184.6kJ)=-369.2kJ[/tex]

The expression for enthalpy change for the reaction will be,

[tex]\Delta H_{rxn}=\Delta H_1+\Delta H_2+\Delta H_3[/tex]

[tex]\Delta H_{rxn}=(74.6kJ)+(-95.7kJ)+(-369.2kJ)[/tex]

[tex]\Delta H_{rxn}=-390.3kJ[/tex]

Therefore, the value of [tex]\Delta H_{rxn}[/tex] for the reaction is, -390.3 kJ

Answer:

A. H2P04

Explanation:

Answer:

180 p

Explanation:

Energy refers to the capacity of doing work.

Amount charged by an electrical company = 15 p per unit of energy (kWh)

As 1 W = 1000 kW,

[tex]500W=\frac{500}{1000}kW=0.5\,kW[/tex]

Also, 1 day = 24 hours.

Cost of running a 500 W freezer = 0.5 kW freezer for 1 hour = [tex]15\times 0.5=7.5\,p[/tex]

Therefore,

cost of running a 0.5 kW freezer for a day ( 24 hours ) = [tex]7.5\times 24=180\,p[/tex]

Amount charged by an electrical company = 15 p per unit of energy (kWh)

As 1 W = 1000 kW,

[tex]500W=\frac{500}{1000}kW=0.5\,kW[/tex]

Also, 1 day = 24 hours.

Cost of running a 500 W freezer = 0.5 kW freezer for 1 hour = [tex]15\times 0.5=7.5\,p[/tex]

Therefore,

cost of running a 0.5 kW freezer for a day ( 24 hours ) = [tex]7.5\times 24=180\,p[/tex]

Answer:

Both contain a hydroxyl group on the second carbon.

Neither contain a hydroxyl group on an end chain carbon.

Explanation:

2,2-butanediol Formula: C4H10O2

2,3,4-pentanetriol Formula: C5H12O3

Both contain a hydroxyl group on the second carbon.

Neither contain a hydroxyl group on an end chain carbon.

Answer: nucleus

Explanation: the bigger the nucleus there more reactive the atom is

Answer:

The larger an atom is, the more reactive it will be.

It helps to think about the size of an atom with the location of the electrons and nucleus in mind. You know that protons are positively charged and electrons are negatively charged, therefore there is a level of attraction between these two oppositely charged subatomic particles. This attraction helps stabilize the atom.

Now, in a larger atom, with more electrons are those electrons (specifically the valence electrons) going to be closer or further from the nucleus than in a smaller atom?

They will of course be further from the nucleus and therefore further from the positively charged nucleus. This makes it easier for the valence electrons to leave the atom and form an ionic bond or to interact with another atom to form a covalent bond.

If electrons can leave more easily, then the atom is more likely to react.

Answer:

Check Explanation

Explanation:

In this case the Mushroom would get energy from decomposing dead plants and animals in the soil/ground

The plant would get energy from the sun (simplified)

the rabbit would get energy from eating the plant

in this case the wolf would energy from eating the rabbit but in a normal setting the wolf could get energy from eating any animal

Answer:

Explanation: A wolf gets its energy from food and water

A rabbit gets its energy from food and water too

A plant get it energy from sunlight, rain

A mushroom also get its energy from dead plant/animal’s

If this wasn’t the answer you wanted I’m sorry

Answer:

Need more details to answer correctly.

Do you mean in general why are populations decreasing?

Well for jaguars this is due to poaching and deforestation.

For Sloths this is due to deforestation.

In an ecosystem, the jaguars and sloths  are not growing and thriving due to deforestation and poaching.

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

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Answer:

CrO

Explanation:

0.765g Cr

0.235g O

O = 16g/mol

Cr = 52g/mol

O     2-

Cr  2+, 3+, 6+

0.765 + 0.235 = 1

so 76.5% Cr

23.5% O

76.5/52 = 1.47/1.47 = 1

23.5/16 = 1.47/1.47 = 1

CrO

Answer:

N = -3

H = +1

O = -2

Cl = +1

Explanation:

The balanced Equation of the reaction above is:

NH3 + 3HOCl ----> NCl3 + 3H2O

Where NH3 is ammonia;

HOCl is Oxochlorate (I) acid

NCl3 is nitrogen trichloride

H2O is water

Nitrogen in both Ammonia and Nitrogen trichloride has an oxidation state of -3. It shares three electrons with each of the three atoms of hydrogen and chlorine

Hydrogen in both Oxochlorate (I) acid and in water has an oxidation state of +1. Each atom shares an election with oxyen in both compounds.

Oxygen in both Oxochlorate (I) acid and water has an oxidation state of -2. Each atom shares two electrons with neighboring atoms; in HOCl, it shares with chlorine and hydrogen, while in H2O, it shares with two atoms of hydrogen.

Chlorine in both Oxochlorate (i) acid and Nitrogen trichloride has an oxidation state of +1. It shares an electron with each of it's neighboring bonded atoms.

Answer:

“The answer to this question” is more general. The preposition to denotes assignment - that the answer is being “applied” to the question, whether the answer is right or wrong. Conceptually, that makes a lot more sense than the previous one. This is also the more common usage.

Answer:

D. Na2CO3

Explanation:

I'm just guessing tbh

Answer:

It is calcualted based ion the  yield from the limiting reactant

Explanation:

Answer: C. Based in previous data, ten hurricanes may occur in the year 2013.

Explanation:

Inference can be explained as conclusion made from an existing evidence or facts. Option C, best fits an inference statement.

Answer:

C

Explanation:

because everything looks like opinions

Answer: The molarity of [tex]Br^-[/tex] anions in the chemist's solution is 0.0084 M

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in ml

moles of [tex]FeBr_3[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{0.0411g}{295.6g/mol}=0.00014mol[/tex]

Now put all the given values in the formula of molality, we get

[tex]Molarity=\frac{0.00014\times 1000}{50}=0.0028[/tex]

As 1 mole of [tex]FeBr_3[/tex] gives = 3 moles of [tex]Br^-[/tex]

0.0028 moles of [tex]FeBr_3[/tex] gives = [tex]\frac{3}{1}\times 0.0028=0.0084 moles[/tex] of [tex]Br^-[/tex]

Thus the molarity of [tex]Br^-[/tex] anions in the chemist's solution is 0.0084 M

Answer:

read below

Explanation:

When the zebra eats grass, it gets energy from the sun that has been stored in the grass. Similarly, the lion obtains energy stored in the zebra. The zebra and lion both obtain the sun's energy indirectly from the energy that the grass obtained through photosynthesis.

Answer/Explanation:

It gets energy from the sun that was inside of the grass.

It happens like this:

Sun gives energy to grass, grass gives energy to zebra.

Sun ---> Grass ---> Zebra

Answer:

It's the bottom layer.  

Explanation:

Scientists use the Law of Superposition to determine the relative age of a layer of sedimentary rock:

The oldest rock layer is at the bottom of an undisturbed bed.

Thus, Layer A in the figure below was deposited first.

Answer:

After one-half life: 16 mg

After 2-half lives: 8 mg

After 3-half lives: 4 mg

After 4-half lives: 2 mg

After 5-half lives: 1 mg

(5 half-lives) x (8 days/half-life) = 40 days  

or doing it the mathematical way:  Let z be the number of days to be found:

1 mg = 32 mg x (1/2)^(z / 8 days)  

1/32 = (1/2)^(z / 8 days)  

log (1/32) = (z / 8 days) x log (1/2)  

z / 8 days = log (1/32) / log (1/2)

z = 8 days x log (1/32) / log (1/2) = 40 days

Explanation:

Iodine-131 has a half-life of 8 days, then it would it take for the number of unstable nuclei in the sample to be reduced from 1,000 to 125 is 512 days.

Total time of the reduction of any substance from an initial concentration to a particular concentration will be calculated as:

T = (t)ⁿ, where

n = number of half lives

t = half life time = 8 days

1st half life: 1000 → 500

2nd half life: 500 → 250

3rd half life: 250 → 125

So number of half life times is 3. On putting values we get,

T = (8)³

T = 512 days

Hence total duration of time is 512 days.

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Answer:it b

Explanation:

I've done that before

Answer:

The Answer is C or 3

Explanation:

I took the test

Answer:

Foliation is developed by stress and fire while layering is developed by the embedding of fine and coarse deposits. Foliation is caused due to an alteration of minerals from pressure and heat while layering is developed by seasonal changes

Explanation:

Banding occurs when two different mineral compositions alternate in thin layers (typically 1 mm to 1 cm). The two types of layers typically contain the same minerals, but in different proportions, giving the rock a striped appearance. A foliation is defined by its banding.

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Answer:

d)carbon(iv)oxide/carbon(ii)oxide

e)Calcium,carbon,oxygen

f)carnonhydride

g)Carbonhydrate

h)hydrogen+oxygen

I)Iron sulphide

j)Magnesiumoxide

m)magnesium hydroxide+hydrogen gas

d)carbon dioxide

Answer:

[tex]\large \boxed{\text{528.7 g} }[/tex]

Explanation:

It often helps to write the heat as if it were a reactant or a product in the thermochemical equation.

Then you can consider it to be 11018 "moles" of "kJ"  

We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.

M_r:                      32.00

              2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 8H₂O + 11 018 kJ

n/mol:                                                                  7280

1. Moles of O₂

The molar ratio is 25 mol O₂:11 018 kJ

[tex]\text{Moles of O}_{2} = \text{7280 kJ} \times \dfrac{\text{25 mol O}_{2}}{\text{11 018 kJ}} = \text{16.52 mol O}_{2}[/tex]

2. Mass of O₂

[tex]\text{Mass of C$_{8}$H}_{18} = \text{16.52 mol O}_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \textbf{528.6 g O}_{2}\\\text{The reaction requires $\large \boxed{\textbf{528.67 g O}_{2}}$}[/tex]

Answer:

A positron is the antimatter counterpart of an electron (also called anti-electron). ... The spin, a type of angular momentum carried by the electron and positron, is the same for both. However, the electron and positron have the opposite charge. The electron has a negative charge, and the positron has positive charge.

Answer:

-1

Explanation:

Because it is the smallest sub-atomic particle

Answer:

An increase in the amount of CO2 well increase the rate of photosynthesis, Carbon dioxide concentration will directly affect the rate of photosynthesis as it is used in the photosynthesis reaction.Increased amount of CO2 will increase the rate of photosynthesis to a certain limit, after which a further increase in its amount will no longer increase the rate any further.

Hope this helps.

Cheers! :)

Answer:

hydroxide ion / OH-

Explanation:

Basic solutions have a greater concentration of hydroxide ions than hydrogen (H+) ions

Answer:

Water H2O

Explanation:

A solvent is defined as being able to dissolve other substances, the fertilizer is being dissolved in the water prior to watering the plants, therefore the water is the solvent in this case.