where does energy come from? newsela

To prepare 267 mL of  0.25M NaCl, we need to take 38.29 mL of 1.75M NaCl solution and add water to it until it makes the final volume up to 267 mL.

We need to prepare the solution of 0.25 M NaCl using 1.75 M NaCl solution, we can use the dilution formula:

[tex]C_1V_1 = C_2V_2[/tex]

where [tex]C_1[/tex], [tex]V_1[/tex] is the concentration and the volume of the initial solution, [tex]C_2[/tex], [tex]V_2[/tex] is the concentration and the volume of the final solution.

We know the final concentration and the final volume that we are required to make. So we can use the above relation to find  [tex]V_1[/tex] of the solution:

[tex]V_1 = (C_2 * V_2) / C_1[/tex]

Now after substituting the values in the relation, we get:

[tex]V_1 = (0.25 M x 267 mL) / 1.75 M\\V_1 = 0.03829 L or 38.29 mL[/tex]

So to prepare 267 mL of  0.25M NaCl, we need to take 38.29 mL of 1.75M NaCl solution and add water to it until it makes the final volume up to 267 mL.

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Answer:

Dissociation

Explanation:

When HCl and NaOH are mixed with water, the HCl and NaOH molecules interacts with the water, forming what is known as ions. Ions are atoms with electric charge.

When HCl, it forms H+ and Cl-. The mixture is acid because what define a mixture as acid is the amount of H+ ions.

When NaOH mixes with water, it forms Na+ and OH- ions. The amount of OH- ions in a mixture defines it as basic.

The statement " It has two carbon-carbon double bonds" is correct. because Q is a kind of unsaturated hydrocarbon.

What is unsaturated hydrocarbon?

The type of compound which contain double bond or triple bond can be considered as unsaturated hydrocarbon. Unsaturated hydrocarbon can decolorized bromine water.

Two kinds of unsaturated hydrocarbon will obtain, alkene and alkyne.

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Answer:

57.7 miles.

Explanation:

Hello there!

In this case, according to the given information, it is possible to set up the initial miles-cost ratio as shown below:

[tex]\frac{30mi}{\$2.60}[/tex]

Thus, we can find the the driven miles with $5 by multiplying as follows:

[tex]\frac{30mi}{\$2.60} *\$5\\\\=57.7mi[/tex]

Best regards!

The miles' the car can run with the fuel cost $5 has been 57.69 miles.

The given car run for a 30 miles by 1 gallon of the fuel. The given cost of fuel has been $2.60. Thus, for 30 miles, the cost of fuel has been driven to be $2.60.

The miles that can be driven by the car with $5 has been given by unitary method. The expression has been driven as:

[tex]\$2.60=30\;\rm miles\\\$5=\dfrac{30}{2.60}\;\times\;5\;miles\\\$5=57.69\;miles[/tex]

The miles' the car can run with the fuel cost $5 has been 57.69 miles.

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Answer: sun is directly over the equator

Explanation:

There are only two times of the year when the Earth's axis is tilted neither toward nor away from the sun, resulting in a "nearly" equal amount of daylight and darkness at all latitudes.

Answer: 2M + 3Q2 -----> 2MQ3

Explanation:

2 Ms either side, and 6 Qs either side

Answer:

I'm not sure what your asking

Explanation:

whats the question......

Answer:

I don't understand you. Please elaborate

Answer:

A: catalyst

Explanation:

In Chemistry, the rate of reaction of chemical elements (reactants) can be sped to produce a chemical compound or elements (products), through the addition of a catalyst that is unaffected by the reaction.

This ultimately implies that, to speed up a chemical reaction, add a catalyst that is unaffected by a reaction.

For example, an enzyme refers to a biological catalyst that is typically used to speed up (accelerate) the rate of a chemical reaction by lowering the activation energy of its reactants.

An enzyme can be defined as a biological catalyst that typically lowers the activation energy of a biological reaction. When the activation energy of a reaction is low, the rate of the reaction would be faster. Therefore, an enzyme speeds or catalyzes the rate of a reaction by lowering its activation energy.

Generally, an increase in temperature increases or speeds up the rate of a reaction while low temperature limits or reduces the rate of a reaction. The optimal temperature for enzymes in the human body is around 37 degrees celsius.

Answer: The sample absorbed 3061.565J

Explanation:

Given that  

Mass of water  = 335g

Initial temperature  = 24.5°C

Final temperature = 26.4°C

Heat  absorbed by the sample is given as  = mass x specific heat of water x  temperature change

Heat  absorbed,q=mCΔt

The specific heat of water,C  = 4.81J/g°C

Therefore,  Heat absorbed,q  = 335 x 4.81h x (26.4  - 24.5)  = 3061.565J

Answer:

2660.57 J

Explanation:

26.4 - 24.5 = 1.9

335 x 4.18 x 1.9 = 2660.57 J

That is the correct answer.

Answer:

2L of nitrogen gas will be needed

Explanation:

Based on the following reaction:

N₂ + 3H₂ → 2NH₃

1 mole of nitrogen reacts with 3 moles of hydrogen to produce 2 moles of ammonia.

If 6L of hydrogen (In a gas, the volume is directly proportional to the moles, Avogadro's law) react, the volume of nitrogen gas required will be:

6L H₂ * (1mol N₂ / 3 moles H₂) =

Answer:

[tex]a=-3.37\ m/s^2[/tex]

Explanation:

Given that,

A car accelerates negatively from 35m/s to 8m/s in 8s.

We need to find the car's acceleration.

Initial speed, u = 35 m/s

Final speed, v = 8 m/s

Time, t = 8 s

The acceleration of an object is equal to the rate of change of velocity. So,

[tex]a=\dfrac{v-u}{t}[/tex]

Put all the values,

[tex]a=\dfrac{8-35}{8}\\\\a=-3.37\ m/s^2[/tex]

So, the acceleration of the car is equal to [tex]-3.37\ m/s^2[/tex].

Answer:

activation energy

the minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction.

effective collisions

An effective collision is defined as one in which molecules collide with sufficient energy and proper orientation, so that a reaction occurs.

ineffective collisions

An ineffective collision (A) is one that does not result in product formation. An effective collision (B) is one in which chemical bonds are broken and a product is formed.

Answer:

i believe it's D

Explanation:

Answer:

D

Explanation:

Answer:

a. Sn or Si ⇒ Sn

b. Br or Ga ⇒ Ga

c. Sn or Bi ⇒ similar in size

d. Se or Sn ⇒ Sn

Explanation:

The larger atom has a larger atomic radius. We have to consider how varies the atomic radius for chemical elements in the Periodic Table. In a group (column), the atomic radius increases from top to bottom while in a period (file), it increases from right to left.

a. Sn or Si ⇒ Sn

They are in the same group. Sn is on the top, so it has a larger atomic radius.

b. Br or Ga ⇒ Ga

They are in the same period. Ga is located at the left so it has a larger atomic radius.

c. Sn or Bi ⇒ similar

They are not in the same group neither the same period. Bi is located more at the bottom, so it would be larger than Sn, but Bi is also at the right side, so it would be smaller than Bi. Thus, they have comparable sizes.

d. Se or Sn⇒ Sn

They are not in the same group neither the same period. Se is located at the top and right side compared to Sn, so Sn is the larger atom.

Answer:

double bond to an atom

a lone pair

a single bond to an atom

Explanation:

6:c

7: might be ice but im not really sure, hope you do well.

Explanation:

Answer:

true

Explanation:

drought is a period of unusually persistent dry weather that persists long enough to cause serious problems such as crop damage and/or water supply shortages. The severity of the drought depends upon the degree of moisture deficiency, the duration, and the size of the affected area.

Answer:

I never did this but i think its d 37.5٪ lmk if i got it right pls and srry if i didnt

Answer:

Physical i think, because it says, "The shoes are green, made of cotton, and rubber sole" everything in the passage described a physical property

Explanation:

tell me if im wrong, good luck

Answer:

physical

Explanation:

its listing a size 8, which eliminates chemical and mechanical. Also it lists their green, which eliminates structural, leaving physical left

Answer:

1 and 3

Explanation:

oh this one lol,, hope it helps

Answer:

1 and 3

Explanation:

hope this helps :)

Answer:

mass = 17.2 grams

Explanation:

q = mcΔT => m = q/cΔT = 187j / (0.90j/g°C)(35.6°C - 23.5°C) = 17.2g

Answer:

Yes.

Explanation:

Wasting household water does not ultimately remove that water from the global water cycle, but it does remove it from the portion of the water cycle that is readily accessible and usable by humans. Also, "wasting" water wastes the energy and resources that were used to process and deliver the water.

Answer:

I feel like there should be more parts to this question but I think it depends on how you got your water. If you waste water after you got it from a local stream yourself, you wasted your body energy but no real electricity of any kind. If the water is processed and filtered and you end up wasting it, I guess it counts as energy being wasted too? Because the sole purpose was to bring you clean water but you didn't utilize it

Answer:

Solids, liquids, gases - all matter - are made up of atoms (or other things, like molecules, that are made from atoms)! ELEMENTS are the kinds of atoms that we can have. Carbon is an element, hydrogen is an element, and so is oxygen. ... Atoms can join together - they form bonds together - to make MOLECULES.

Answer: The solubility of this compound in pure water is 0.012 M

Explanation:

Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as [tex]K_{sp}[/tex]

The equation for the ionization of the  is given as:

[tex]Ca(OH)_2\rightarrow Ca^{2+}+2OH^-[/tex]  

By stoichiometry of the reaction:

1 mole of  [tex]Ca(OH)_2[/tex] gives 1 mole of [tex]Ca^{2+}[/tex] and 2 mole of [tex]OH^-[/tex]

When the solubility of  [tex]Ca(OH)_2[/tex] is S moles/liter, then the solubility of [tex]Ca^{2+}[/tex]  will be S moles\liter and solubility of [tex]OH^-[/tex] will be 2S moles/liter.

[tex]K_{sp}=[Ca^{2+}][OH^{-}]^2[/tex]

[tex]6.5\times 10^{-6}=[S][2S]^2[/tex]

[tex]S=0.012M[/tex]

Thus solubility of this compound in pure water is 0.012 M

Answer:

75m

Explanation:

Answer:

Oxidation - reduction reaction which is called redox reaction.

Explanation:

The type of reaction that is a part of another type but treated separately is called Oxidation - reduction reaction.

Thus is because they usually involve 2 separate half reactions which are oxidation reactions that involve loss of electrons and then reduction equations which involve gain of electrons.

They are treated separately for example when sodium reacts with chlorine to form sodium chloride.

2Na + Cl2 = 2NaCl

Now, sodium undergoes oxidation by loosing elctrons and it's half reaction is;

2Na → 2Na​^(+) + 2e^(-)

​​Meanwhile chlorine undergoes reduction by gaining electrons and its half reaction is;

Cl2 + 2e^(-) → 2Cl^(-)

Answer:

Option C, Smut

Explanation:

Corn smut is a condition in which mushroom-like tumors or galls appear on different part of the plant. This is caused by fungus Ustilago zeae. Corn smut is edible and appears grayish white with spony texture in the early stages of the infection promptly found on corn ear or tassel.

Hence, option C is correct

option c is the right answer❤️