Select the correct answer. What is heat of vaporization?
A. It is the heat required to change a substances temperature by 1C
B. It is the heat required to change a gram of substance from a solid to a liquid
C. It is the heat required to change a substance from a solid directly to a gas
D. It is the heat required to change a gram of substance from a liquid to a gas
E. It is the heat required to separate one substance into two substances

Answer:

they would repel

Explanation:

unlike charges attract while like ones repel.

Answer:

  98.9%

Explanation:

2 moles of I₂ are required for each mole of Mg, so the reaction is limited by the available I₂. The 3.56 moles of I₂ should react with 1.78 moles of Mg to produce 1.78 moles of MgI₂. Instead, we get 1.76 moles of MgI₂.

The yield is 1.76/1.78 × 100% ≈ 98.876%

The yield is 98.9% of the quantity expected based on available reactants.

Answer:

Kc = [Pb²⁺]³.[PO₄³⁻]²

Explanation:

Let's consider the following reaction at equilibrium.

Pb₃(PO₄)₂(s) ⇄ 3 Pb²⁺(aq) + 2 PO₄³⁻(aq)

The concentration equilibrium constant is the product of the concentrations of the products raised to their stoichiometric coefficients divided by the product of the concentrations of the reactants raised to their stoichiometric coefficients. It only includes gases and aqueous species.

Kc = [Pb²⁺]³.[PO₄³⁻]²

This equilibrium constant is known as the solubility product of Pb₃(PO₄)₂.

Answer: Recharge

Explanation:

To solve this we must be knowing each and every concept related to groundwater recharge. Therefore, the transfer of surface water into the ground to become groundwater is known as groundwater recharge.

The water that is added to the aquifer and through unsaturated zone after percolation (or infiltration) following any storm rainfall event is known as groundwater recharge.

In the natural world, rivers, lakes, streams, rain, and snowmelt all contribute to groundwater recharge. Other surface water trickles and through soil, eventually connecting with a source of water underneath the surface, while other surface water has evaporated or enters another watershed.

Therefore, the transfer of surface water into the ground to become groundwater is known as groundwater recharge.

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Answer:

CATION

Explanation:

It's one is the action and the mother is a cation.

Answer:

1.7 moles of ethanol would be needed.

Explanation:

* Calculate the moles of ethanol needed to produce 1.70mol of water. Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.

First off, we have to state the equation for the reaction.

So we know that;

ethanol + oxygen → acetic acid + water

This leads us to;

C2H5OH + O2 → CH3COOH + H2O

1                    1         1                    1

To obtain the moles of ethanol needed to produce 1.70mol of water, we look at the stoichiometry of the reaction above.

1 mol of ethanol produces 1 mole of water

x mol of thanol would produce 1.7 mol of water

Thus we have;

1 = 1

x = 1.7

x = 1.7 moles of ethanol would be needed.

Answer:

The answer is "Option b"

Explanation:

In this question first we calculates the moles in F-, HF, and in HCL, which can be defined as follows:

Formula:

[tex]\ Number \ of \ moles\ = \ Molarity \times \ Volume \ in \ litter[/tex]

[tex]\ moles \ in\ F- = 0.100 \ M \times 0.0250 L\\\\[/tex]

                     [tex]=\ 0.0025 \ moles[/tex]

[tex]\ moles \ in \ HF \ = 0.126M \times 0.0250 L[/tex]

                       [tex]= 0.00315 \ moles[/tex]

[tex]\ moles \ in \ HCl = 0.0100M \times 0.00500 L[/tex]

                       [tex]= 0.00005 \ moles[/tex]

[tex]\ Reaction: \\\\F - + H+ \rightarrow HF[/tex]

[tex]\Rightarrow \ moles \ in \ F- = 0.0025 \\\\\Rightarrow \ moles \ in \ H+ = 0.00005 \\\\ \Rightarrow \ moles \ in \ HF = 0.00315\\\\ \ total \ moles = 0.00250 -0.0000500 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0.00315 + 0.00005\\\\\ total \ moles =0.00245 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0.00245[/tex]

[tex]\ total \ volume \ in \ the \ solution = \ V = \ 0.0300 L\\\\ after \ addition \ of \ HCl \ the \ concentration \ of \ F- \ = 0.00245\ moles \div V[/tex]

                                                                                [tex]=\frac{ 0.00245 \ moles }{0.0300L}\\\\= \frac{245 \times 10^4}{300 \times 10^5} \\\\= \frac{245}{3000} \\\\ = 0.0817 M[/tex]

Answer:

1 mole of the gas occupies 22. 4L at O0C at 1atm pressure. Hence, the correct option is C.

Explanation:

Answer:

THE SPECIFIC HEAT OF THE ALLOY IS 0.9765 J/g K

Explanation:

Mass of alloy = 33 g

Initial temperature of alloy = 93°C

Mass of water = 50 g

Initail temp. of water = 22 °C

Heat capacity of calorimeter = 9.20 J/K

Final temp. = 31.10 °C

specific heat of alloy = unknown

specific heat capacity of water = 4.2 J/g K

Heat = mass * specific heat * change in temperature = m c ΔT

Heat = heat capcity * chage in temperature = Δ H * ΔT

In calorimetry;

Heat lost by the alloy = Heat gained by water + Heat of the calorimeter

                     mc ΔT = mcΔT + Heat capacity * ΔT

33 * C * ( 93 - 31.10) = 50 * 4.2 * ( 31.10 -22) + 9.20 * ( 31.10 -22)

33 * C * 61.9 = 50 * 4.2 * 9.1 + 9.20 * 9.1

2042.7 C = 1911 + 83,72

C = 1911 + 83.72 / 2042.7

C = 1994.72 /2042.7

C =0.9765 J/g K

The specific heat of the alloy is 0.9765 J/ g K

Answer:

Explanation:

Step 1: Data given

The equilibrium constant, Kc, for the following reaction is 4.76 * 10^-4 at 431 K

The equilibrium concentration of Cl2(g) is  0.233 M

Step 2: The balanced equation

PCl5(g)  ⇄ PCl3(g) + Cl2(g)

Step 3: The initial concentration

[PCl5]= Y M

[PCl] = 0M

[Cl2] = 0M

Step 4: Calculate the concentration at equilibrium

[PCl5] = Y + X M = Y - 0.233 M

[PCl]= XM = 0.233 M

[Cl2]= XM = 0.233 M

Step 5: Define Kc

Kc =  [Cl2]* [PCl3] / [PCl5]

4.76 * 10^-4 = 0.233² / (Y -0.233)

0.000476 = 0.05429 / (Y - 0.233)

Y - 0.233 = 0.05429 / 0.000476

Y - 0.233 = 114.05 M

Y = 114.283 M = the initial concentration

The concentration of PCl5 at the equilibrium is 114.05 M

Answer:

I think that the fire will continue burning, because the oil and water don't mix and the water is heavier (denser) than oil, so the oil will go up and the fire with it. That's why because the gas station have sand instead of water

Water is heavier than oil. Because oil is lighter and immiscible with water, it will form a separate layer above the surface of the water and continue to burn when water is poured on a large oil fire. As a result, the fire won't be put out.

A small amount of water will instantly sink to the bottom of a pan or deep fryer filled with hot, burning oil and explode there. The Scientific American claims that the characteristics of oils explain why they do not mix with water.

Oil or petroleum-related fires cannot be put out with water. Water sinks below the oil because it is heavier than oil and does not float, allowing the fire to continue to burn. Oil and petroleum fires can be put out with fire extinguishers or sand.

The temperature of the burning substance is lowered by water. The fire goes out when the temperature drops below the burning substance's ignition temperature. Here, the water serves as an acclimatizer.

Thus,  it will form a separate layer above the surface of the water and continue to burn when water is poured on a large oil fire.

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Answer:

[tex]\large \boxed{\text{-486 kJ}}[/tex]

Explanation:

You calculate the energy required to break all the bonds in the reactants.

Then you subtract the energy needed to break all the bonds in the products.

                      2H₂   +   O₂ ⟶ 2H-O-H

Bonds:          2H-H    1O=O       4H-O

D/kJ·mol⁻¹:     436      498          464

[tex]\begin{array}{rcl}\Delta H & = & \sum{mD_{\text{reactants}}} - \sum{nD_{\text{products}}}\\& = & 2 \times 436 +1 \times 498 - 4 \times 464\\&=& 1370 - 1856\\&=&\textbf{-486 kJ}\\\end{array}\\\text{The enthalpy of reaction is $\large \boxed{\textbf{-486 kJ}}$}.[/tex]

Answer: 1.311 × 10^18 photons are produced in each pulse

Explanation: Please see the attachments below

Answer:10 grams of CO2

Explanation:

Yeild= exp. yeild÷ thoretical yeild × 100

Yeild= 73.3÷73.4 × 100

Yeild= 0.1 ×100

Yeild= 10

Answer:

1. Acid-Base Reaction

Explanation:

Fe(OH)2(s) + HCl(aq) = FeCl2(aq) + H2O(l)

base               acid

This a reaction between base and acid.

Ferrous hydroxide is an inorganic alkaline compound whereas hydrochloric acid is an acid. The reaction between Fe(OH)₂and HCl is an acid-base reaction. Thus, option 1 is correct.

An acid-base reaction is a chemical change that occurs and takes place when the reactant constitutes an acid and a base. They are characterized by the exchange of protons that results in the formation of conjugate bases and acids or salt.

The acid-base chemical reaction is shown as,

Fe(OH)₂(s) + HCl(aq) ⇒ FeCl₂(aq) + H₂O(l)

Here, ferrous hydroxide is a base with hydroxide ions and hydrochloric acid is an acid with hydrogen ions. HCl donates its proton to form water molecules with hydroxide ions of ferrous hydroxide.

Therefore, in option 1. the reaction is an acid-base reaction.

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Answer:

At equilibrium the rate of the forward reaction is equal to the rate of the backward reaction.

When the product of a reaction at equilibrium is increased the equilibrium will shift left or to the reactant side. As a result the excess product will get converted to reactant. This is in accordance to Le Chatelier's principle.

Le Chatelier's principle states that when a system is subjected to stress the equilibrium will shift in a direction to minimize effect of the stress.

Thus the products added to the system at equilibrium will make the equilibrium shift to the reactant side, the rate of the reverse or backward reaction will increase.

Explanation:

Hope This Helps Amigo!

Answer:

1.  2.28 g

2. 0.82 g

3. 1.35 g

4. 36 %

5. 59 %

6. 2.17 g

7. 95 %

Explanation:

Hello,

1. In this case, the mass of the unknown mixture is obtained by subtracting the mass of the dish plus sample and the mass of the dish:

m = 26.57 g- 24.29 g = 2.28 g

2. In this case, the mass of the NaCl recovered is obtained by subtracting the mass of the dish plus NaCl and the mass of the dish:

m = 68.66 g- 67.84 g = 0.82 g

3. In this case, the mass of the sand recovered is obtained by subtracting the mass of the filter paper plus sand and the mass of the filter paper:

m = 37.69 g- 36.34 g = 1.35 g

4. The percentage of NaCl is computed by considering its mass and the mass of the unknown mixture:

% NaCl = 0.82 g / 2.28 g * 100 % = 36 %

5. The percentage of sand is computed by considering its mass and the mass of the unknown mixture:

% sand = 1.35 g / 2.28 g * 100 % = 59 %

6. Here,we have to add the mass of NaCl and sand:

m = 0.82 g + 1.35 g = 2.17 g

7. Finally, the percent recovery is obtained by diving the total recovered mass by the total obtained mass of the mixture:

% recovery = 2.17 g / 2.28 g * 100 % = 95 %

Best regards.

Answer: The molecules in the thermometer's liquid spread apart.

Explanation:

Mercury is the only metal that remains liquid at room temperature. It has a high coefficient of expansion therefore the its level rises when exposed to a temperature range. It can detect a slight change in temperature. It has a high  boiling point.

When the thermometer is placed in the water to measure the temperature, the molecules of thermometer liquid that is mercury only will spread due to high coefficient of expansion. This can be seen as rise in temperature.

Answer:

B

Explanation:

Just did the test

Cathode ray experiments of the following provides evidence to support Thomson's hypothesis about electrons.

Rutherford's gold leaf experiment demonstrated that the atom is essentially empty space with such a tiny, compact, positively-charged nucleus. Thomson had proposed the plum pie model of the atom, which featured negatively-charged electrons buried within a favorably "soup." Since most of the alpha particles flow through an atom directly without being deflected, contrary to what Thomson's model predicted, the majority of a space inside of an atom is empty. As a result, the Thomson model of a molecule was disproved.

According to Thomson's model, every atom is made up of negative charges "plums" surrounded in positively charged "pudding," or electrons with a soup of positive ion to balance their negative charges. Hans Geiger and Arthur Marsden's 1909 gold foil test refuted the 1904 Thomson model.

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Answer:

2-chloropentanal

Answer:

2-chloropentanal

Explanation:

ch3-ch2-ch-ch(cl)-ch=o IUPAC name

     H   H         H   H

H - C - C - C - C - C = O

     H   H    H  Cl

So as can be seen 2 as the Chlorine is on the second carbon.

Chloro because of the chlorine.

Pent because there's 5 carbon

al because there's an aldehydes

Aldehyde =  −CHO

2-chloropentanal

Answer: D

Explanation: The elements in two compunds switch places

Answer:

Ba(OH)2(aq)+H2SO4(aq) gives us 2BaH+H2O

Explanation:

Answer:

ΔG = -2.17 kJ/mol

Explanation:

ΔG of a reaction at any moment could be obtained thus:

ΔG = ΔG° + RT ln Q

Where ΔG° is standard change in free energy of a particular reaction (7.53kJ/mol for the reaction of the problem, R is gas constant (8.314×10⁻³kJ/molK), T is absolute temperature (298K) and Q is reaction quotient of the reaction.

For the reaction:

dihydroxyacetone phosphate ⇄ glyceraldehyde−3−phosphate

Q is defined as:

Q = [glyceraldehyde−3−phosphate] / [dihydroxyacetone phosphate]

Replacing values in ΔG formula:

ΔG = 7.53kJ/mol + 8.314×10⁻³kJ/molK × 298.15K ln [0.00200M] / [0.100M]

ΔG = -2.17 kJ/mol

Answer: The Gibbs free energy of the reaction is -114629.4 J

Explanation:

To calculate the Gibbs free energy of the reaction, we use the equation:

[tex]\Delta G^o=-RT\ln K_{eq}[/tex]

where,

[tex]\Delta G^o[/tex] = Gibbs free energy of the reaction = ?

R = Gas constant = [tex]8.314 J/K.mol[/tex]

T = temperature of the reaction = 298 K

[tex]K_{eq}[/tex] = equilibrium constant of the reaction = [tex]1.24\times 10^{20}[/tex]

Putting values in above equation, we get:

[tex]\Delta G^o=-(8.314J/mol.K\times 298K\times \ln (1.24\times 10^{20}))\\\\\Delta G^o=-114629.4J[/tex]

Hence, the Gibbs free energy of the reaction is -114629.4 J

Answer:

93.15 %

Explanation:

We have to start with the chemical reaction:

[tex]CaCl_2~+~Na_2CO_3~->~CaCO_3~+~NaCl[/tex]

Now, we can balance the reaction:

[tex]CaCl_2~+~Na_2CO_3~->~CaCO_3~+~2NaCl[/tex]

Our initial data are the 15.71 g of [tex]CaCl_2[/tex], so we have to do the following steps:

1) Convert from grams to moles of [tex]CaCl_2[/tex] using the molar mass (110.98 g/mol).

2) Convert from moles of [tex]CaCl_2[/tex] to moles of [tex]CaCO_3[/tex] using the molar ratio. ( 1 mol [tex]CaCl_2[/tex]= 1 mol of [tex]CaCO_3[/tex]).

3) Convert from moles of [tex]CaCO_3[/tex] to grams of [tex]CaCO_3[/tex] using the molar mass. (100 g/mol).

[tex]15.71~g~CaCl_2\frac{1~mol~CaCl_2}{110.98~g~CaCl_2}\frac{1~mol~CaCO_3}{1~mol~CaCl_2}\frac{100~g~CaCO_3}{1~mol~CaCO_3}=14.16~g~CaCO_3[/tex]

Finally, we can calculate the yield percent:

[tex]%~=~\frac{13.19~g~CaCO_3}{14.16~g~CaCO_3}*100=93.15~%[/tex]

I hope it helps!

The percentage yield obtained when excess sodium carbonate, Na₂CO₃, is added to a solution containing 15.71 g CaCl₂ is 93.2%

Molar mass of CaCl₂ = 40 + (35.5×2) = 111 g/mol

Mass of CaCl₂ from the balanced equation = 1 × 111 = 111 g

Molar mass of CaCO₃ = 40 + 12 + (16×3) = 100 g/mol

Mass of CaCO₃ from the balanced equation = 1 × 100 = 100 g

SUMMARY

From the balanced equation above,

111 g of CaCl₂ reacted to produce 100 g of CaCO₃

From the balanced equation above,

111 g of CaCl₂ reacted to produce 100 g of CaCO₃.

Therefore,

15.71 g of CaCl₂ will react to produce = [tex]\frac{15.71 * 100}{111} \\\\[/tex] = 14.15 g of CaCO₃.

Thus, the theoretical yield of of CaCO₃ is 14.15 g

Actual yield of CaCO₃ = 13.19 g

Theoretical yield of CaCO₃ = 14.15 g

[tex]Percentage yield = \frac{Actual}{Theoretical} * 100\\\\= \frac{13.19}{14.15} * 100\\\\[/tex]

Therefore, the percentage yield of the reaction is 93.2%

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Answer:

The rates of decay of radioactive elements

Explanation:

The age of a rock in years is called its absolute age. Geologists find absolute ages by measuring the amount of certain radioactive elements in the rock. When rocks are formed, small amounts of radioactive elements usually get included.

Answer:

Explanation:

The fluid containing virus is harvested from the eggs. For inactivated influenza vaccines (i.e., flu shots), the vaccine viruses are then inactivated (killed), and the virus antigen is purified. The manufacturing process continues with quality testing, filling and distribution.

Answer:

(D.)

The core of the pyruvate dehydrogenase complex is made up of eight catalytic trimers that make up the E2 component.

Explanation:

Eight trimers assemble as a hollow truncated cube, which forms the core of the multi-enzyme complex, known as the E2 complex in human pyruvate dehydrogenase complex.

Answer:

The appropriate reagent is: H3PO2.

Explanation:

H3PO2 is in charge of eliminating the amino group by diazotization, remember that the amino group had previously achieved bromination at positions m; that is to say that it achieved in the beginning that the three bromine atoms of 1,2,4 tribromobenzene were introduced in the meta positions among themselves, which finally corresponds as part of the last reaction to the 1,3,5-tribromobenzene position.

Answer:

Explanation:

it is based on le chatliers principles

the left side of reaction you have 4 moles , where as at the right hand side you have 2 moles,,,,

so when you increase the pressure the reaction will shift towards the lower moles producing reaction that is reaction move towards forward in you case.