Answers
Answer:
-65 kJ
Explanation:
To use Hess's Law, you need to combine the equations in a way that results in the desired equation. To add reactants/products, just add the equations and their subsequent heat of reactions. Subtracting reactants/products involves flipping the signs of enthalpies, duplicating reactants/products involves multiplying the coefficients and enthalpies by a desired number.
A + 2B --> C + D
+ B --> 2C + D
------------------------------------
A + 3B --> 3C + 3D
In this case, you only need to add the equations together to get the desired equation. Because you just add the equations, combine each equations' heat of reaction.
(-20 kJ) + (-45 kJ) = -65 kJ
The overall heat of reaction of the desired reaction is -65 kJ.
Related Questions
If the concentrations of a weak acid and its conjugate base are increased from 0.1 M and 0.05 M, respectively, to 0.2 M and 0.1 M, the solution's buffer capacity will _________.
Answers
If we increase the concentrations of a weak acid and its conjugate base by the amounts shown, the buffer capacity will remain the same.
What is buffer capacity?The term buffer capacity is generally used to describe how much of the acid or base that can be neutralized by a buffer before there can be a change in the pH.
In this case, if we increase the concentrations of a weak acid and its conjugate base by the amounts shown, the buffer capacity will remain the same.
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What is the purpose of adding base in the aldol condensation reaction? choose the best answer.
Answers
Base is used in aldol condensation reaction
because it is an organic reaction to form enolate ion, the OH bond present in base help to remove Acidic hydrogen of enolate ion.
There is a bell at the top of a tower that is 45m high. The bell weighs 190N (N=Newtons). The bell has potential energy. The formula for Potential energy is PE = mgh or mass x gravity x height. Gravity is 9. 8 m/s^2. What is the bell’s potential energy?
Answers
Since the bell weighs 190 N and is 45 m high, the bell’s potential energy is 8550 J
To answer the question, we need to know what potential energy is.
What is potential energy?This is energy due to position. It is given by PE = mgh where
m = mass, g = acceleration due to gravity and h = height of object.Also, W = mg = weight of object.
So, PE = Wh
The bell's potential energyNow, given that the bells weight 190 N and is 45 m high,
W = 190 N and h = 45 m.So, PE = Wh
= 190 N × 45 m
= 8550 Nm
= 8550 J
So, the bell’s potential energy is 8550 J
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21) What is the percent by mass of bromine in the compound MgBr₂?
A) 13.2%
B) 43.4%
C) 56.6%
D) 86.8%
Answers
Answer:
D 86.8%
Explanation:
Two bromines mole wt = 2 * 79.9 = 159.8 gm (from periodic table)
Mg = 24.3 gm
159.8 / ( 159.8 + 24.3) = .868 = 86.8 %
5. How much water would need to be added to 750 mL of a 2.8 M HCl solution to
make a 1.0 M solution?
6. If I add 25 mL of water to 125 mL of a 0.15 M NaOH solution, what will the molarity of the diluted solution be?
7. If I add water to 100 mL of a 0.15 M NaOH solution until the final volume is 150 mL, what will the molarity of the diluted solution be?
8. How much 0.05 M HCl solution can be made by diluting 250 mL of 10 M HCl?
9. I have 345 mL of a 1.5 M NaCl solution. If I boil the water until the volume of the solution is 250 mL, what will the molarity of the solution be?
10.
How much water would I need to add to 500 mL of a 2.4 M KCl solution to make a 1.0 M solution
please help me
Answers
The values of molarity and volumes for the given questions are 2,100 mL, 0.75 M, 0.1 M, 50,000 mL, 2.07 M and 1,200 mL respectively.
What is the relation between the molarity & volume of solution?Relation between the molarity and volume of the solution will be shown by the following equation:
M₁V₁ = M₂V₂, where
M₁ & V₁ is the molarity and volume of one solution whereas M₂ & V₂ are the molarities and volume of the another solution.
Required volume of water needed to add at 750 mL of a 2.8 M HCl solution to make a 1.0 M solution will be calculated by using the above formula:V₂ = (750)(2.8) / (1) = 2,100 mL
Required molarity of diluted solution obtained on adding 25 mL of water to 125 mL of a 0.15 M NaOH solution will be calculated by using the above formula:M₂ = (0.15)(125) / (25) = 0.75 M
Required molarity of diluted solution obtained on adding 100 mL of a 0.15 M NaOH solution until the final volume is 150 mL will be calculated by using the above formula:M₂ = (100)(0.15) / (150) = 0.1 M
Required volume of HCl of 0.05M HCl can be made by diluting 250 mL of 10 M HCl will be calculated by using the above formula:V₂ = (10)(250) / (0.05) = 50,000 mL
Molarity of the resultant solution is:M₂ = (1.5)(345) / (250) = 2.07 M
Required volume of water to add on KCl solution is:V₂ = (2.4)(500) / (1) = 1,200 mL
Hence required values of molarity and volume are 2,100 mL, 0.75 M, 0.1 M, 50,000 mL, 2.07 M and 1,200 mL respectively.
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Which acid/base pair will give an equivalence point that cannot be predicted solely by a general knowledge of acid and base strength
Answers
The acid/base pair that give equivalence point that Cannot be predicted by general knowledge is NaOH and HCI ONH.
What is an Acid and base?An Acid is a substances that is corrosive in nature and turn blue lithmus paper to red which it react with base to produce salt and water.
Acid dissolve metals.
Base is a substance that turn red lihthmus paper to blue and react with acid to produce salt and water.
Therefore, The acid/base pair that give equivalence point that Cannot be predicted by general knowledge is NaOH and HCI ONH.
The question is incomplete as the options were not given. The options were gotten from another website.
Select the correct answer below:
ONaOH and HCI ONH,
HC ONH, and CH, COOH
NaOH and Christmas, COOH
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Calculate the pH of a solution with [H+] = 5.6 x 10^-8
Answers
Answer:
Approximately [tex]7.25[/tex].
Explanation:
If the concentration of [tex]{\rm H^{+}}[/tex] ions in a solution is [tex]x\; {\rm M}[/tex], the [tex]{\rm pH}[/tex] of that solution would be [tex](-\log_{10}(x))[/tex].
Note that the base of the logarithm in this calculation should [tex]10[/tex]. One way to be sure is to state the base explicitly. Using the change of base rule of logarithms:
[tex]\begin{aligned}-\log_{10}(x) = -\frac{\ln(x)}{\ln(10)}\end{aligned}[/tex].
In this question, it is implied that the concentration of [tex]{\rm H^{+}}[/tex] in the given solution is [tex]5.6 \times 10^{-8}\; {\rm M}[/tex], such that [tex]x = 5.6 \times 10^{-8}[/tex]. Using the equations above:
[tex]\begin{aligned}& \text{pH of this solution} \\ =\; & -\log_{10}(x) \\ =\; & -\frac{\ln(x)}{\ln(10)} \\ =\; & -\frac{\ln(5.6 \times 10^{-8})}{\ln(10)} \\ \approx\; & 7.25\end{aligned}[/tex].
Alice kicks a 0.25 kg soccer ball with 0.5 N of force. What force does the ball exert on Alice’s foot as she kicks it?
N
Answers
Answer:
0.5 N
Explanation:
The ball pushes back with the same force as Alice applies to it
Answer:
0.5 Newtons
Explanation:
did it on edge and got it right
Mercury-203 undergoes beta minus decay. 203 80 hg → 203 81 tl ? the subatomic particle produced is a(n) . 203 80 hg → 203 81 tl 0 -1 e is this the correct balanced equation? .
Answers
The correct balanced equation of a beta decay undergone by Mercury-203 is as follows:
203 80 Hg → 203 81 + 0 -1 e
What is beta decay?Beta decay in radioactivity refers to the release of a beta particle by a radioactive element.
Beta particle is characterized by the possession of mass number 0 and atomic number -1.
This means that if Mercury-203 undergoes beta decay, the atomic number of the resulting isotope will be +1 as follows:
203 80 Hg → 203 81 Tl + 0 -1 e
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What are 5 pros of coal of energy?
Answers
Answer:
What are the pros of coal energy? ans :
Huge Global Reserves.
Not an Intermittent Energy Source.
Reliable Fuel.
Inexpensive Energy Source.
Minimal Wastes, Consumable Byproducts
Smokeless Alternatives
Compatible With Other Energy Sources.
The mass of an unidentified metal sphere is 133 grams. Students determine the
volume of the metal sphere by placing it in a graduated cylinder filled with 25
milliliters of water. The volume of the water rises to 40 milliliters when the metal
sphere is placed into the graduated cylinder. The students calculate the density
of the metal sphere in order to determine the identity of the metal using the
chart below.
What is the identity of the metal?
Aluminum
Tin
Iron
Cobalt
Answers
Given the data from the question, the identity of the unknown metal having a of mass 133 g is Cobalt
What is density?The density of a substance is simply defined as the mass of the subtance per unit volume of the substance. Mathematically, it can be expressed as
Density = mass / volume
How to determine the density Mass = 133 gVolume of water = 25 mL Volume of water + metal = 40 mL Vol of metal = 40 – 25 = 15 mL Density =?Density = mass / volume
Density = 133 / 15
Density = 8.86 g/mL
Comparing the density of the unknown metal (i.e 8.86 g/mL) with those given in the chart in the question above, we can conclude that the unknown metal is Cobalt
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Calculate the concentration of a solution of nitric acid in which 2.6g is dissolved into 2.0 L
Answers
How many moles of water are produced from the following reaction, when 275 kJ of energy is given off?
4 NH3 + 3 O2 → 2 N2 + 6 H2O ΔH = -1530 kJ
Answers
The moles of water are produced from the given reaction, when 275 kJ of energy is given off is 1.08 moles.
How do we calculate moles of water?The mole (symbol mol) is the SI base unit of material quantity. The amount of substance in an object or sample is a measure of how many elementary entities of a certain substance are present.
Given chemical reaction is:
4NH₃ + 3O₂ → 2N₂ + 6H₂O
From the stoichiometry of the reaction it is clear that 6 moles of water molecule is produced.
Actual moles will be calculated by using the enthalpy and energy value as:
Actual moles of H₂O = 275kJ × (6 mol H₂O)/1530kJ) = 1.08 moles.
Hence required moles of H₂O is 1.08 moles.
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WILL GIVE BRAINLIEST
Mussels need both Ca2+ and CO32- to make their shells. The data showed that the ocean Ca2+ has not changed, so Ca2+ is not the problem.
To determine the CO32- concentration in the ocean, we can use the DIC measurement and the ocean’s pH.
Use the reaction equation above to answer the question on the relationship between pH and CO32- concentration.
Would a decrease in pH mean an increase or decrease in CO32- concentration?
Answers
Answer: Decrease
"Carbon dioxide reacts with seawater to form carbonic acid, which releases hydrogen ions, reducing pH"
Sourced from https://yaleclimateconnections.org/2008/06/covering-ocean-acidification-chemistry-and-considerations/
So basically the ocean is absorbing the CO32- and that lowers the pH as well lowers the amount of CO32- readily available.
This is all I could find on this subject though ;'(
Please Please Please help + show the work please! :)
Find the number of grams 9.30 x 10^-3 mole of SmO
Answers
So, there are about (9.30 * 10^-3)(160.36)=1.49 grams
Molar mass of SmO or sodium methylate is 160g/mol
Now
No of moles =Given mass /Molar massGiven mass
No of moles ×Molar mass9.3×10^{-3}×1601.488gWhich statement describes abiotic factors in an environment? chickens run around a farm. soil retains water and nutrients. bacteria use energy to reproduce. plants compete for sunlight in an ecosystem.
Answers
Answer:
soil retains water and nutrients
Explanation:
abiotic factors
water
soil
pH
Answer: B
Explanation:
what was happening to the H20 when the lines on the graph were mostly flat? What kind of energy was being added to the system?
Answers
Answer: A heating curve graphically represents the phase transitions that a substance undergoes as heat is added to it.
The plateaus on the curve mark the phase changes. The temperature remains constant during these phase transitions.
Water has a high boiling point because of the strong hydrogen bonds between the water molecules; it is both a strong hydrogen bond donor and acceptor.
The first change of phase is melting, during which the temperature stays the same while water melts. The second change of phase is boiling, as the temperature stays the same during the transition to gas
Explanation:
That's latent heat of vaporization.
Water boils at 100°CThe graph increases still 100°Conce it reaches boiling point it yields a straight line because of latent heat after all molecules are evaporated then the graph rises backFill in the blank.
_______ is defined as the energy of motion.
_______ is proportional to the average kinetic energy of the sample of matter.
Temperature indicates the _______ of heat flow.
Heat flows only from _______ objects to _______ objects.
The _______ scale is the absolute temperature scale where zero degrees is defined as an absolute zero.
_______ is the lowest possible temperature where no heat energy would remain in the substance and molecules and atoms would stop moving.
_______ is the net movement of particles from regions of high concentration to regions of low concentration.
The transfer of heat from a hot to a cold body would stop when _______ is reached.
_______ is the quantity of heat that a body of matter absorbs or releases when it experiences a temperature change of 1 Kelvin.
Answers
Answer:
Kinetic energy, Kelvin temperature, direction, warmer, cooler, Kelvin, Absolute zero
Explanation:
THe answers are in order and when there is a comma move to the next ______
1. Given the following reaction, answer the questions that follow:
C3H8+5 02
3 CO₂ + 4H₂O
a) If you begin with 3.5 moles of C3H8 and 6.2 moles of O₂, find the moles of carbon dioxide produced_
b) Find the mass of CO₂ produced using your work in step (a) above.
Answers
Answer:
See below
Explanation:
From the equation you can see 5 mole O2 results in 3 moles CO2
( this is the limiting reagent because C3H8 : O2 is 1:5)
6.2 / 5 * 3 = 3.72 moles CO2 produced
CO2 weighs ~ 44 gm/mole 44 gm/mole * 3.72 mole = 163.68 gm of CO2
Which gas is produced when Mg(s) is added to HCl(aq)?
A.
O2
B.
H2
C.
Cl2
D.
CO2
Answers
Answer:
B h2
Explanation:
Answer:H2
Explanation:
Which molecule is hexanal?
Answers
Answer:is A.
Explanation:Because six carbon straight chain aldehyde it is clear liquid with an atomspheric pressure boiling point of 131 degree Celsius.
Which of the following are functions of the nose?
I. Filters the air before it goes to the lungs.
II. Helps us keep our balance
III. Helps us smell different odors.
I and II
I and III
II and III
I, II, and III
Answers
Answer:
The answer should be I and III
Answer:
| and |||
Explanation:
Please answer this question for me
Answers
Answer:
True.
Explanation:
Ternary acids end in -ic if the polyatomic anion ends in -ate.
True
Explanation:
It is clearly given in the hint
I have two solutions : solution A has 6 moles of solute in 2 L of solvent; solution B has 6 moles of solute in 1 L of solvent . Which one is more concentrated ?
Answers
Answer:
Many people have a qualitative idea of what is meant by concentration. Anyone who has made instant coffee or lemonade knows that too much powder gives a strongly flavored, highly concentrated drink, whereas too little results in a dilute solution that may be hard to distinguish from water. In chemistry, the concentration of a solution is the quantity of a solute that is contained in a particular quantity of solvent or solution. Knowing the concentration of solutes is important in controlling the stoichiometry of reactants for solution reactions. Chemists use many different methods to define concentrations, some of which are described in this section.
Molarity
The most common unit of concentration is molarity, which is also the most useful for calculations involving the stoichiometry of reactions in solution. The molarity (M) is defined as the number of moles of solute present in exactly 1 L of solution. It is, equivalently, the number of millimoles of solute present in exactly 1 mL of solution:
molarity=molesofsolutelitersofsolution=mmolesofsolutemillilitersofsolution(4.5.1)
(4.5.1)molarity=molesofsolutelitersofsolution=mmolesofsolutemillilitersofsolution
The units of molarity are therefore moles per liter of solution (mol/L), abbreviated as MM . An aqueous solution that contains 1 mol (342 g) of sucrose in enough water to give a final volume of 1.00 L has a sucrose concentration of 1.00 mol/L or 1.00 M. In chemical notation, square brackets around the name or formula of the solute represent the molar concentration of a solute. Therefore,
[sucrose]=1.00M(4.5.2)
(4.5.2)[sucrose]=1.00M
is read as “the concentration of sucrose is 1.00 molar.” The relationships between volume, molarity, and moles may be expressed as either
VLMmol/L=L(molL)=moles(4.5.3)
(4.5.3)VLMmol/L=L(molL)=moles
or
VmLMmmol/mL=mL(mmolmL)=mmoles(4.5.4)
(4.5.4)VmLMmmol/mL=mL(mmolmL)=mmoles
Figure 4.5.14.5.1 illustrates the use of Equations 4.5.34.5.3 and 4.5.44.5.4 .
alt
Figure 4.5.14.5.1 : Preparation of a Solution of Known Concentration Using a Solid Solute
Example 4.5.14.5.1 : Calculating Moles from Concentration of NaOH
Calculate the number of moles of sodium hydroxide (NaOH) in 2.50 L of 0.100 M NaOH.
Given: identity of solute and volume and molarity of solution
Asked for: amount of solute in moles
Strategy:
Use either Equation 4.5.34.5.3 or Equation 4.5.44.5.4 , depending on the units given in the problem.
Solution:
Because we are given the volume of the solution in liters and are asked for the number of moles of substance, Equation 4.5.34.5.3 is more useful:
molesNaOH=VLMmol/L=(2.50L)(0.100molL)=0.250molNaOHmolesNaOH=VLMmol/L=(2.50L)(0.100molL)=0.250molNaOH
Exercise 4.5.14.5.1 : Calculating Moles from Concentration of Alanine
Calculate the number of millimoles of alanine, a biologically important molecule, in 27.2 mL of 1.53 M alanine.
Please indicate which of the compounds will yield postive results for the permanganate, ninhydrin, and ceric ammonium nitrate tests by placing them in the appropriate boxes.
Answers
The compounds will yield Positive results for the permanganate, ninhydrin, and ceric ammonium nitrate tests are
permanganate test= ethene,
ninhydrin=aspasyic acid Phenylalanine
ceric ammonium nitrate test= methanol
What is a compound?Generally, A compound is simply defined as a substance made up of two or more different chemical elements held together by chemical bonds that are difficult to break.
In conclusion, For the permanganate test= ethene,
ninhydrin=aspasyic acid Phenylalanine
ceric ammonium nitrate test= methanol
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A 2.0 l container of oxygen had a pressure of 3.2 atm. what volume would be necessary to decrease the pressure to 1.0 atm? use the formula: p1v1 = p2v2 0.625 l 0.64 l 6.4 l 64 l
Answers
The volume that would be necessary to decrease the pressure to 1.0 atm is mathematically given as
v2=6.4l
What volume would be necessary to decrease the pressure to 1.0 atm?Question Parameter(s):
A 2.0 l container of oxygen had a pressure of 3.2 atm
Generally, the equation for the is mathematically given as
P1v1=p2v2
Therefore
v2=piv1/p2
v2=2*3.2/1
v2=6.4l
In conclusion, the volume is
v2=6.4l
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Answer:
CExplanation:
Can someone please help me? i will give brainlist
Answers
Answer:
B. Design homes that can be built on stilts where flooding is likely to occur.
C. Replace power lines that have been damaged by severe weather.
Explanation:
[tex]Hope[/tex] [tex]this[/tex] [tex]helps![/tex] [tex]:)[/tex]
Describe the importance of plaster of paris
Answers
Answer:
plaster is important because of the many uses you can make out of plaster
Which of the following is NOT a function of the skeletal system?
A. Exchanges oxygen and carbon dioxide
B. Produce red blood cells
C. Protects the organs
D. Stores calcium and phosphorus
(This is a science question btw)
Answers
Answer:
D. Stores calcium and phosphorus
Explanation:
Correct me if I'm wrong
The phosphorus atom in pcl3 would be expected to have a:.
Answers
The phosphorus atom in Phosphorus trichloride (PCl₃) would be expected to have a partial positive charge.
What is a partial positive charge?A molecule has a partial positive charge when it presents differences in electric charges along the molecule.
A molecule that has a partial positive charge is said to be polar because can generate polar bonds.
Moreover, phosphorus trichloride (PCl₃) is a molecule that forms a colorless substance used in the inorganic chemistry industry.
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