Considering the temperature vs. time graph below, how does the temperature at the beginning of a change of state compare with the temperature at the end of the change?

- The temperature is always lower.
- The temperature is always the same.
- The temperature is usually lowest
- The temperature is usually higher.​

Answer:

they're all fake

Explanation:

I think it's sodium hydroxide

Explanation:

sodium hydroxide is a base

Answer:

Option D, Calcium and Aluminum levels

Explanation:

The coal fired power plant releases huge amount of particulate and gaseous emissions such as mercury, sulphur dioxide, nitrogen oxide etc. When there is rain, these gaseous and particulate matter comes to the ground along with rain water and pollute the soil. There are also chances of acid rain due to the presence of sulphur dioxide. Polluted soil and acid rain negatively impact the growth of the plants and causes leaching of Aluminium thereby decreasing the availability of calcium for the plants. Thus, the trees die. Hence, if the amount of Aluminium and Calcium in soil is determined, one can easily deduce the cause of death of trees.

Hence, option D is correct

Answer:

[tex]3.9*10^4 J[/tex]

Explanation:

Answer:

[tex]\boxed {\boxed {\sf 39, 225 \ Joules}}}[/tex]

Explanation:

Since we are given the mass, temperature, and specific heat, we should use the following formula to calculate heat energy.

[tex]q=mc \Delta T[/tex]

We have 375 grams of water, the specific heat of water is 4.184 J/g ° C, and the temperature is raised 25 degrees Celsisus. Therefore:

Substitute the values into the formula.

[tex]q= (375 \ g)(4.184 \ J/g \textdegree C)(25 \textdegree C)[/tex]

Multiply the first two values together. The units of grams will cancel.

[tex]q=1569 \ J/ \textdegree C(25 \textdegree C)[/tex]

Multiply again. This time, the degrees Celsius cancel, so we are left with only the units of Joules.

[tex]q= 39225 \ J[/tex]

39,255 Joules of heat must be absorbed by the water.

Answer: There are [tex]0.617 \times 10^{4}[/tex] moles present in [tex]3.72 \times 10^{27}[/tex] atoms of iron.

Explanation:

According to the mole concept, there are [tex]6.022 \times 10^{23}[/tex] atoms present in one mole of a substance.

Hence, moles present in [tex]3.72 \times 10^{27}[/tex] atoms are calculated as follows.

[tex]Moles = \frac{3.72 \times 10^{27}}{6.022 \times 10^{23}}\\= 0.617 \times 10^{4} mol[/tex]

Thus, we can conclude that there are [tex]0.617 \times 10^{4}[/tex] moles present in [tex]3.72 \times 10^{27}[/tex] atoms of iron.

Answer:

1) PV > nRT, because the real volume of the gas would be more than the ideal

volume.

Explanation:

According to the ideal gas equation; PV = nRT.  Let us recall that this equation only holds under ideal conditions.

Gases exhibit ideal behavior under high temperature and low pressure. At higher pressure, the real volume of the gas is larger than the ideal volume of the gas.

Thus, at high pressure,  PV > nRT, because the real volume of the gas would be more than the ideal  volume.

Answer:

1) PV > nRT, because the real volume of the gas would be more than the ideal volume.

Explanation:

just took the test :)

Answer:

h2

Explanation:

Answer: Solubility of NaOH is greater and there are more OH- ions in solution.

Explanation: Reactions : NaOH (s) ⇒ Na+ (aq) + OH- (aq)

Mg(OH)2 (s) ⇒ Mg2+ (aq) + 2 OH-(aq)

Although in same amount of moles, Mg(OH)2 produces

two (OH-)-ions in water solution, solubility of Mq(OH)2 is smaller.

Concentration [OH-]ions is smaller in saturated  water solution

of Mg(OH)2

Answer:

see picture below

Explanation:

The mechanism is in the following picture.

In the first step, the lone pair of oxygen (from the OH) as it's a strong activating group in the molecule, will go to the ring. This will cause that the double bond of the ring of the ortho position, attacks as nucleophyle to the Br2, causing the breaking of the bond.

In the second step, the bromine ion substract the hydrogen from the ortho position, and then, by resonance, the pair of electrons returns to the oxygen of the phenol.

Answer:

Root system will become larger or extend farther

Explanation:

If nutrient in soil decrease, the plant's roots system will likely become larger and extend out deeper and farther to get all the nutrients it possibly can

Answer:

Ofc D. bc if the temp decreases, that means it is getting colder u dummy! But if it increases, it is getting warmer.

Explanation:

I got it right on USATestprep for using common sense, mark me the brainliest.

Answer:

Lower the pH slightly

Explanation:

The mixture of HF, hydrofluoric acid and KF, potassium fluoride produce a buffer that is defined for the equilibrium:

HF(aq) → H⁺(aq) + F⁻(aq)

The buffer can maintain the pH of a solution despite the addition of strong bases or acids.

The reaction of HF with Ca(OH)2 is:

2HF + Ca(OH)2 → 2H2O + CaF2

That means the calcium hydroxide is decreasing the concentration of HF. Based on the equilibrium, the H+ and F- ions will decrease in order to produce more HF. As H+ is decreasing due the equilibrium and not for the addition of a strong base, the pH is decreasing slightly.

Answer: b because Potential energy is converted to kinetic energy as a stationary object begins to move.

Explanation:

Answer:

(C) NO2 has covalent bonds.

Answer:

Finally, coagulation occurs and reinforces the platelet plug with threads of fibrin which are like a molecular binding agent. The hemostasis stage of wound healing happens very quickly.

Explanation:

Hope it helps u

FOLLOW MY ACCOUNT PLS PLS

Answer:

(1) Income Associated with the Production Process

(a) Compensation of employees

(b) Taxes and subsidies on products and

production .

(2) Property Income

(a) Investment income:

• Dividends and withdrawals from income of

quasi-corporations

• Reinvested earnings

• Interest

(b) Rent .

I hope this is correct :-)

Answer: It depends equilibrium constant K

Explanation:   You need to to have reaction formula.

If K >> 1 then concentrations of products are much bigger than

concentrations of reactants. If K < < 1, concentration of products is small.

In order to balance the chemical equation, the coefficient of Na should be 2.

Answer:

No, your missing some bonds

Answer:

Explanation:

fdcdf

Answer:

not a mineral but is a “mineraloid

Explanation:

not mineral

Explanation: its an element but it is not a mineral

Answer:

P(C₆H₆) = 0.2961 atm

Explanation:

I found an exercise pretty similar to this, so i'm gonna use the data of this exercise to show you how to do it, and then, replace your data in the procedure so you can have an accurate result:

"At a certain temperature the vapor pressure of pure benzene (C6H6) is measured to be 0.63 atm. Suppose a solution is prepared by mixing 79.2 g of benzene and 115. g of heptane (C7H16) Calculate the partial pressure of benzene vapor above this solution. Round your answer to 2 significant digits. Note for advanced students: you may assume the solution is ideal".

Now, according to the data, we want partial pressure of benzene, so we need to use Raoul's law which is:

P = Xₐ * P°    (1)

Where:

P: Partial pressure

Xₐ: molar fraction

P°: Vapour pressure

We only have the vapour pressure of benzene in the mixture. We need to determine the molar fraction first. To do this, we need the moles of each compound in the mixture.

To get the moles:   n = m / MM

To get the molar mass of benzene (C₆H₆) and heptane (C₇H₁₆), we need the atomic weights of Carbon and hydrogen, which are 12 g/mol and 1 g/mol:

MM(C₆H₆) = (12*6) + (6*1) = 78 g/mol

MM(C₇H₁₆) = (7*12) + (16*1) = 100 g/mol

Let's determine the moles of each compound:

moles (C₆H₆) = 79.2 / 78 = 1.02 moles

moles (C₇H₁₆) = 115 / 100 = 1.15 moles

moles in solution = 1.02 + 1.15 = 2.17 moles

To get the molar fractions, we use the following expression:

Xₐ = moles(C₆H₆) / moles in solution

Xₐ = 1.02 / 2.17 = 0.47

Finally, the partial pressure is:

P(C₆H₆) = 0.47 * 0.63

Hope this helps

We are given:

251 mL sample of 0.45M HCl added to 455 mL distilled water

Whack a mole! (finding the number of moles):

We know that in order to find molarity, we use the formula:

Molarity = number of moles / Volume (in L)

so, number of moles is:

Number of moles = Molarity * Volume(in L)

now let's plug the values for the HCl solution to find the number of moles

Number of moles = 0.45M * 0.251 L

Number of moles = 0.113 moles

Time to concentrate (finding the final concentration):

Total final volume = 251 mL + 455 mL = 706 mL = 0.706 L

Number of moles of HCl = 0.113 moles

Molarity = Number of moles / Volume (in L)

Molarity = 0.113 / 0.706

Molarity = 0.16 M

___________________________________________________________

BONUS METHOD TIME!!!

We know the relation:

M1 * V1 = M2 * V2

where M1 and M2 are the initial and final molarities and V1 and V2 are initial and final volumes respectively

notice that I didn't mention that the volume has to be in Liters, that's because of the units being concerned with both sides of the equation, say I have the volume in mL and want to convert both these volumes to L, I would divide both sides by 1000, which would NOT change the overall value

Now, plugging values in this equation

(0.45) * (251) = (251 + 455)* (M2)

112.95 = (706)(M2)

M2 = 112.97/706                                [dividing both sides by 706]

M2 = 0.16 Molar

Answer:

Metamorphic

Explanation:

Answer: thats metamorphic rock

Answer:

5.72 × 10⁻³¹ m

Explanation:

Step 1: Given and required data

Step 2: Calculate the longest wavelength of light (λ) with energy sufficient to break this bond

We will use the Planck-Einstein relation.

E = h × c/λ

λ = h × c/E

λ = (6.63 × 10⁻³⁴ J.s) × (3.00 × 10⁸ m/s)/(348 × 10³ J) = 5.72 × 10⁻³¹ m

Answer:  Ratio : 4, 3, 4, 3 are the answers.

Explanation: