chem midterm!

Which of the following describes the changes in forces of attraction that occur as H2O changes phase from a liquid to a vapor?

Hydrogen bonds between H2O molecules are broken.

The energy diagram for the reaction X + Y → Z is shown above. The addition of a catalyst to this reaction would cause a change in which of the indicated energy differences?

I and II only

. . . Ca3(PO4)2(s) + . . . H3PO4(l) → . . . Ca(H2PO4)2(s) When the equation above is balanced and all coefficients are reduced to lowest whole-number terms, what is the coefficient for H3PO4(l) ?

4

The following questions refer to the below. M+ is an unknown metal cation with a +1 charge. A student dissolves the chloride of the unknown metal, MCl, in enough water to make 100.0 mL of solution. The student then mixes the solution with excess AgNO3 solution, causing AgCl to precipitate. The student collects the precipitate by filtration, dries it, and records the data shown below. (The molar mass of AgCl is 143 g/mol.) Mass of unknown chloride, MCl: 0.74 g Mass of filter paper: 0.80 g Mass of filter paper plus AgCl precipitate: 2.23 g

A

Which of the following behaves most like an ideal gas at the conditions indicated? A H2(g) molecules at 10-3 atm and 200oC B O2(g) molecules at 20 atm and 200oC C SO2(g) molecules at 20 atm and 200oC D NH3(g) molecules at 20 atm and 200oC E NH3(g) molecules at 20 atm and 300oC

A H2(g) molecules at 10-3 atm and 200oC

Which of the following statements best explains why an increase in temperature of 5-10 Celsius degrees can substantially increase the rate of a chemical reaction?

The number of effective collisions between reactant particles is increased.

Step 1: NO(g) + O3(g) → NO2(g) + O2(g) Step 2: NO2(g) + O(g) → NO(g) + O2(g) A reaction mechanism for the destruction of ozone, O3(g), is represented above. In the overall reaction, NO(g) is best described as

a catalyst

Which of the following best helps to account for the fact that the F- ion is smaller than the o2- ion?

b. F- has a larger nuclear charge than o2- has

Consider the atoms of the following elements. Assume that the atoms are in the ground state. The atoms that contains only one electron in the highest occupied energy sublevel is:

c. Ga

If 87.5 percent of a sample of pure 131I decays in 24 days, what is the half-life of 131I?

8 days

M+ is an unknown metal cation with a +1 charge. A student dissolves the chloride of the unknown metal, MCl, in enough water to make 100.0 mL of solution. The student then mixes the solution with excess AgNO3 solution, causing AgCl to precipitate. The student collects the precipitate by filtration, dries it, and records the data shown below. (The molar mass of AgCl is 143 g/mol.) Mass of unknown chloride, MCl = 0.74 g Mass of filter paper = 0.80 g Mass of filter paper plus AgCl precipitate = 2.23 g Which of the following diagrams best represents the AgNO3 solution before the reaction occurs? Note: water molecules are represented by the symbol A B C D

A

A 0.5 mol sample of He(g) and a 0.5 mol sample of Ne(g) are placed separately in two 10.0 L rigid containers at 25°C. Each container has a pinhole opening. Which of the gases, He(g) or Ne(g), will escape faster through the pinhole and why? A He(g) will escape faster because the He(g) atoms are moving at a higher average speed than the Ne(g) atoms. B Ne(g) will escape faster because its initial pressure in the container is higher. C Ne(g) will escape faster because the Ne(g) atoms have a higher average kinetic energy than the He(g) atoms. D Both gases will escape at the same rate because the atoms of both gases have the same average kinetic energy.

A He(g) will escape faster because the He(g) atoms are moving at a higher average speed than the Ne(g) atoms.

Which of the following Lewis Diagrams best represent the bonding in the N2O molecule, considering charges? (2.6)

B

Of the three solutions listed in the table above, which one, if any, has the greatest electrical conductivity and why? A 0.1MHC2H3O2(aq)0.1MHC2H3O2(aq) because its molecules have the most atoms. B 0.1MKI(aq)0.1MKI(aq) because KIKI completely dissociates in water to produce ions. C 0.1MCH3OH(aq)0.1MCH3OH(aq) because its molecules can form hydrogen bonds. D All three solutions have the same electrical conductivity because the concentrations are the same.

B 0.1MKI(aq)0.1MKI(aq) because KIKI completely dissociates in water to produce ions.

A rigid metal tank contains oxygen gas. Which of the following applies to the gas in the tank when additional oxygen is added at constant temperature? A The volume of the gas increases. B The pressure of the gas decreases. C The average speed of the gas molecules remains the same. D The total number of gas molecules remains the same. E The average distance between the gas molecules increases.

C The average speed of the gas molecules remains the same.

The diagram above represents the absorption spectrum for a pure molecular substance. Which of the following correctly indicates the type of transition observed for the substance in each of the regions of the absorption spectrum? A Region X: Molecular Vibration, Region Y: Molecular rotation, Region Z: Electronic transition B Region X: Electronic transition, Region Y: Molecular rotation, Region Z: Molecular vibration C Region X: Molecular rotation, Region Y: Molecular vibration, Region Z: Electronic transition D Region X: Electronic transition, Region Y: Molecular vibration, Region Z: Molecular rotation

D Region X: Electronic transition, Region Y: Molecular vibration, Region Z: Molecular rotation

A student prepared five solutions of CuSO4 with different concentrations, and then filled five cuvettes, each containing one of the solutions. The cuvettes were placed in a spectrophotometer set to the appropriate wavelength for maximum absorbance. The absorbance of each solution was measured and recorded. The student plotted absorbance versus concentration, as shown in the figure above. Which of the following is the most likely explanation for the variance of the data point for the 0.600 M CuSO4 solution? A The cuvette into which the 0.600 M solution was placed had some water droplets inside. B The cuvette into which the 0.600 M solution was placed was filled slightly more than the other cuvettes. C The wavelength setting was accidentally moved away from that of maximum absorbance. D The cuvette used for the 0.600 M solution had not been wiped clean before being put in the spectrophotometer.

D The cuvette used for the 0.600 M solution had not been wiped clean before being put in the spectrophotometer.

A 0.20 mol sample of MgCl2(s) and a 0.10 mol sample of KCl(s) are dissolved in water and diluted to 500 mL. What is the concentration of Cl- in the solution? A 0.15 M B 0.30 M C 0.50 M D 0.60 M E 1.0 M

E 1.0 M

The following questions relate to the below information. XY2 → X + Y2 The equation above represents the decomposition of a compound XY2. The diagram below shows two reaction profiles (path one and path two) for the decomposition of XY2. Which of the following most likely accounts for the difference between reaction path one and reaction path two?

the presence of a catalyst in path two

Reaction 1: CaC2(s) + 2 H2O(l) → C2H2(g) + Ca(OH)2(s) Reaction 2: NaOCl(aq) + 2 HCl(aq) → Cl2(g) + NaCl(aq) + H2O(l) Reaction 3: C2H2(g) + Cl2(g) → C2H2Cl2(g) Reaction 2 occurs when an excess of 6 M HCl(aq) solution is added to 100. mL of NaOCL(aq) of unknown concentration. If the reaction goes to completion and 0.010 mol of Cl2(g) is produced, then what was the molarity of the NaOCL(aq) solution?

0.10 M

A 20.0-milliliter sample of 0.200-molar K2CO3 solution is added to 30.0 milliliters of 0.400-molar Ba(NO3)2 solution. Barium carbonate precipitates. The concentration of barium ion, Ba2+, in solution after reaction is

0.160 M

If 0.40 mol of H2 and 0.15 mol of O2 were to react as completely as possible to produce H2O, what mass of reactant would remain?

0.20 g of H2

H3AsO4 + 3 I- + 2 H3O+ → H3AsO3 + I3- + H2O The oxidation of iodide ions by arsenic acid in acidic aqueous solution occurs according to the stoichiometry shown above. The experimental rate law of the reaction is: Rate = k[H3AsO4] [I-] [H3O+] What is the order of the reaction with respect to I-?

1

Gaseous cyclobutene undergoes a first-order reaction to form gaseous butadiene. At a particular temperature, the partial pressure of cyclobutene in the reaction vessel drops to one-eighth its original value in 124 seconds. What is the half-life for this reaction at this temperature?

41.3 sec

The molecular formula and molar mass of two straight-chain hydrocarbons are listed in the table above. Based on the information in the table, which compound has the higher boiling point, and why is that compound's boiling point higher? A C4H10 ,because it has more hydrogen atoms, resulting in more hydrogen bonding B C4H10 , because it has more electrons, resulting in greater polarizability and stronger dispersion forces C C2H6 , because its molecules are smaller and they can get closer to one another, resulting in stronger dispersion forces D C2H6 , because its molecules are more polar, resulting in stronger dipole-dipole attractions

B C4H10 , because it has more electrons, resulting in greater polarizability and stronger dispersion forces

According to the information in the table below, a 1.00 g sample of which of the following compounds contains the greatest mass of oxygen?

b. MgO

The particle diagram above represents an aqueous solution of a weak monoprotic acid. The white circles represent HHatoms. Which of the following shows the species that act as a Brønsted-Lowry base and its conjugate acid, in that order, in the solution?

black dot with two white circles and black dot with 3 black circles

A lewis diagram for the molecule C2H4 is shown below. In the actual C2H4 molecule, the H-C-H bonds angles are closest to

c. 120 degrees

2 MnO4-(aq) + 10 Br-(aq) + 16 H+(aq) → 2 Mn2+(aq) + 5 Br2(aq) + 8 H2O(l) How many electrons are transferred in the reaction represented by the balanced equation above?

10

when a 3.22 g sample of an unknown hydrate of sodium sulfate, Na2SO4 xH2O is heated, H2O (molar mass 18 g) is driven off. The mass of the anhydrous Na2SO4 (molar mass 142 g) that remains is 1.42 g. The value of x in the hydrate is

10

Each student in a class placed a 2.00 g sample of a mixture of Cu and Al in a beaker in a fume hood. The students slowly poured 15.0 mL of 15.8 M HNO3 into their beakers. The reaction between the copper in the mixture and the HNO3 is represented by the equation below. The students observed that a brown gas was released from the beakers and that the solutions turned blue, indicating the formation of Cu2+. The solutions were then diluted with distilled water to known volumes. Cu + 4HNO3 -> Cu(NO3)2 + 2 NO2 + 2H2O The students determined that the reaction produced 0.010 mol of Cu(NO3)2. Based on the measurement, what was the percent of Cu by mass in the original 2.00 g sample of the mixture?(1.4)

32%

Refer to three gases in identical rigid containers under the conditions given in the table below. The average kinetic energy of the gas molecules is A greatest in container A B greatest in container B C greatest in container C D the same in all three containers

D the same in all three containers

Which of the following molecules has a central atom with less than an octet if electrons? (2.5)

BH3

Which of the following diagrams best depicts an alloy if Ni and B (2.4)

C

5 H2O2(aq) + 2 MnO4-(aq) + 6 H+(aq) → 2 Mn2+(aq) + 8 H2O(l) + 5 O2(g) In a titration experiment, H2O2(aq) reacts with aqueous MnO4-(aq) as represented by the equation above. The dark purple KMnO4 solution is added from a buret to a colorless, acidified solution of H2O2(aq) in an Erlenmeyer flask. (Note: At the end point of the titration, the solution is a pale pink color.) Which element is being oxidized during the titration, and what is the element's change in oxidation number?

Oxygen, which changes from -1 to 0

2 NOBr(g) → 2 NO(g) + Br2(g) The equation above represents an elementary step in a chemical reaction. Which of the following is the correct expression for the rate law of the elementary step?

Rate = k[NOBr]2

An experiment was performed to investigate the reaction between ZnZnmetal and Ni2+(aq)Ni2+(aq)at different concentrations. Because the Ni2+(aq)Ni2+(aq)ion is green, the extent of the reaction was determined using spectrophotometric analysis. Four 20.0mL20.0mLstandard solutions of Ni2+(aq)Ni2+(aq)were prepared by dissolving NiCl2⋅6H2ONiCl2⋅6H2O(molar mass 240g/mol240g/mol) in water. The absorbance of each solution was measured; the results are shown both in the table below and in the following plot of the absorbance data. Which of the following equations best represents the reacting species in the reaction between ZnZnmetal and NiCl2(aq)

Zn(s)+Ni2+(aq)→Zn2+(aq)+Ni(s)

In his atomic theory, Dalton proposed that all atoms of a given element are identical. Which of the following observations provides the best evidence that the proposal is incorrect?

a. The mass spectrum of Cu has a peak at 63 amu and another peak at 65 amu.

In which of the following compounds is the mess ratio of chromium to oxygen closest to 1.62 to 1.00?

b. CrO2

Which of the following correctly indicates whether the solid represented by the particulate model shown below conducts electricity and explains why or why not?

c. it does not conduct electricity because its ions cannot move freely within the solid

For element X represented below, which of the following is the most likely explanation for the large difference between the second and third ionization energies? X(g) --> X+(g) + e- IE1= 740 kJ/mol X+(g) --> X2+(g) + e- IE2= 1450 kJ/mol X2+(g) --> x3+(g) +e- IE3= 7730 kJ/mol

c. the electron removed during the third ionization is, on average, much closer to the nucleus than the first two electrons removed were.

Which of the following particulate diagrams best shows the formation of water vapor from hydrogen gas and oxygen gas in a rigid container at 125oC?

its the picture

Which of the following molecules is least soluble in water? A B C D

B!

X2 + Y2 → X2Y2 rate = k[X2] A reaction and its experimentally determined rate law are represented above. A chemist proposes two different possible mechanisms for the reaction, which are given below. Based on the information above, which of the following is true?

Both mechanism 1 and mechanism 2 are consistent with the rate law.

(A) H2SeO4(aq) + 2 Cl-(aq) + 2 H+(aq) → H2SeO3(aq) + Cl2(g) + H2O(l) (B) S8(s) + 8 O2(g) → 8 SO2(g) (C) 3 Br2(aq) + 6 OH-(aq) → 5 Br-(aq) + BrO3-(aq) + 3 H2O(l) (D) Ca2+(aq) + SO42-(aq) → CaSO4(s) (E) PtCl4(s) + 2 Cl-(aq) → PtCl62-(aq) A precipitation reaction

Ca2+(aq) + SO42-(aq) → CaSO4(s)

Step 1: Ce4+ + Mn2+ → Ce3+ + Mn3+ Step 2: Ce4+ + Mn3+ → Ce3+ + Mn4+ Step 3: Mn4+ + Tl+ → Tl3+ + Mn2+ The proposed steps for a catalyzed reaction between Ce4+ and Tl+ are represented above. The products of the overall catalyzed reaction are

Ce3+ and Tl3+

RbCl has a high boiling point. Which of the following compounds is also likely to have a high boiling point, and why?

CsCl , because its elements have very different electronegativities and it is an ionic compound

HSO4- + H2O ⇌ H3O+ + SO42- In the equilibrium represented above, the species that act as bases include which of the following? I. HSO4- II. H2O III. SO42-

II and III

The graph above shows the results of a study of the reaction of X with a large excess of Y to yield Z. The concentrations of X and Y were measured over a period of time. According to the results, which of the following can be concluded about the rate law for the reaction under the conditions studied?

It is first order in [X]

Which of the following has the shortest bond length

N2

Which of the following has the shortest bond length? (2.7)

N2

Which of the following is the conjugate acid of NH2- ?

NH3

The proposed rate-determining step for a reaction is 2 NO2(g)→NO3(g)+NO(g). The graph above shows the distribution of energies for NO2(g) molecules at two temperatures. Based on the graph, which of the following statements best explains why the rates of disappearance of NO2(g) are different at temperature 2 and temperature 1 ?

NO2(g) is consumed at a faster rate at temperature 2 because more molecules possess energies at or above the minimum energy required for a collision to lead to a reaction compared to temperature 1.

The effective nuclear charge experienced by the outermost electron of Na is different than the effective nuclear charge experienced by the outermost electron of Ne. This difference best accounts for which of the following? (1.5)

Na has a lower first ionization energy than Ne

The photoelectron spectra above show the energy required to remove a 1s electron from a nitrogen atom and from an oxygen atom. Which of the following statements best accounts for the peak in the upper spectrum being to the right of the peak in the lower spectrum? (1.6)

Nitrogen atoms have a smaller nuclear charge than oxygen atoms

Cu(s)+2AgNO3(aq)→Cu(NO3)2(aq)+2Ag(s) The reaction between solid copper and aqueous silver nitrate produces solid silver and a blue solution, as represented by the balanced equation shown above. Based on the balanced equation, which of the following identifies the oxidation and reduction half-reactions?

Oxidation Half-reaction Cu(s)→Cu2+(aq)+2e− Reduction Half-reaction Ag+(aq)+e−→Ag(s)

2 H2O2(aq) → 2 H2O(l) + O2(g) ΔH° = −196 kJ/molrxn The decomposition of H2O2(aq) is represented by the equation above. A student monitored the decomposition of a 1.0 L sample of H2O2(aq) at a constant temperature of 300. K and recorded the concentration of H2O2 as a function of time. The results are given in the table below. Which of the following identifies the element(s) being oxidized and reduced in the reaction?

Oxygen is both oxidized and reduced.

An experiment was conducted to determine the rate law for the reaction A2(g)+B(g)→A2B(g). The table above shows the data collected. Based on the data in the table, which statement is correct?

Since the rate law can be expressed as rate=k[A2][B]rate=k[A2][B], doubling the concentrations of A2A2 and BB will quadruple the rate of the reaction.

2 N2O5(g) → 4 NO2(g) + O2(g) A sample of N2O5 was placed in an evacuated container, and the reaction represented above occurred. The value of PN2O5, the partial pressure of N2O5(g), was measured during the reaction and recorded in the table below. Which of the following correctly describes the reaction?

The decomposition of N2O5 is a first-order reaction.

HCl(aq)+NaOH(aq)→NaCl(aq)+H2O(l) A student had two dilute, colorless solutions, HCl(aq)HCl(aq)and NaOH(aq)NaOH(aq), which were at the same temperature. The student combined the solutions, and the reaction represented above occurred. Which of the following results would be evidence that a chemical reaction took place?

The temperature of the reaction mixture increases.

The potential energy as a function of internuclear distance for three diatomic molecules, X2, Y2, and Z2, is shown in the graph below. Based on the data in the graph, which of the following correctly identifies the diatomic molecules, X2, Y2,and Z2? (2.2)

X2 | Y2 | Z2 H2 | N2 | O2

Which of the following has the bonds arranged in order of decreasing polarity?

a. H-F > N-F > F-F

Atoms of Mg combine with atoms of F to form a compound. Atoms of which of the following elements combine with atoms of F in the same ratio?

b. Ba

The diagram above represents the photoelectric effect for a metal. When the metal surface is exposed to light with increasing frequency and energy of photons, electrons first begin to be ejected from the metal when the energy of the photons is 3.3×10−19J Color Wavelength Red: 647−760nm Orange: 585−647nm Yellow: 575−585nm Green: 491−575nm Blue: 424−491nm Violet: 300−424nm Using the wavelength information provided above, what is the color of the light? A Red B Orange C Yellow D Blue

B Orange

Benzene, C6H6 , has the structure shown above. Considering the observation that benzene is only sparingly soluble in water, which of the following best describes the intermolecular forces of attraction between water and benzene? A Benzene is nonpolar, therefore there are no forces between water and benzene. B The H atoms in benzene form hydrogen bonds with the O atoms in water. C Benzene is hydrophobic, therefore there is a net repulsion between water and benzene. D There are dipole-induced dipole and London dispersion interactions between water and benzene.

D There are dipole-induced dipole and London dispersion interactions between water and benzene.

Consider the reaction represented by the equation 2 X + 2 Z → X2Z2. During a reaction in which a large excess of reactant X was present, the concentration of reactant Z was monitored over time. A plot of the natural logarithm of the concentration of Z versus time is shown in the figure above. The order of the reaction with respect to reactant Z is

first order

An ionic crystal is added to water and starts to dissolve as shown in the particulate representation above. Based on the orientation of the water molecules, what can be assumed about the charge of the hydrated particle indicated by the arrow? A The particle is positively charged, because the oxygen atoms in water are attracted to it. B The particle is negatively charged, because hydrogen atoms in water are attracted to it. C The particle is both positively and negatively charged, because the water molecules are attracted to it. D The particle is neutral, because the dipoles of the water molecules neutralize the charge of the particle.

A The particle is positively charged, because the oxygen atoms in water are attracted to it.

A 0.35 g sample of Li(s) is placed in an Erlenmeyer flask containing 100 mL of water at 25°C. A balloon is placed over the mouth of the flask to collect the hydrogen gas that is generated. After all of the Li(s) has reacted with H2O(l), the solution in the flask is added to a clean, dry buret and used to titrate an aqueous solution of a monoprotic acid. The pH curve for this titration is shown in the diagram below Which of the following is the balanced net-ionic equation for the reaction between Li(s) and water?

2 Li(s) + 2 H2O(l) → 2 Li+(aq) + 2 OH−(aq) + H2(g)

Based on the data in the tables above, which of the following statements provides the best prediction for the boiling point of NaCl ? A NaCl will have a lower boiling point than NaF because the coulombic attractions are weaker in NaCl than in NaF . B NaCl will have a boiling point between that of NaF and MgO because the covalent character of the bonds in NaCl is intermediate between that of MgO and NaF. C NaCl will have a higher boiling point than MgO because the ions are spaced farther apart in NaCl . D NaCl will have a higher boiling point than MgO because the energy required to transfer electrons from the anion to the cation is larger in NaCl than in MgO .

A NaCl will have a lower boiling point than NaF because the coulombic attractions are weaker in NaCl than in NaF .

Of the following, the best explanation for the fact that most gases are easily compressed is that the molecules in a gas A are in constant motion B are relatively far apart C have relatively small masses D have a real, nonzero volume E move slower as temperature decreases

B are relatively far apart

When 6.0 L of He(g) and 10. L of N2(g), both at 0oC and 1.0 atm, are pumped into an evacuated 4.0 L rigid container, the final pressure in the container at 0oC is A 2.0 atm B 4.0 atm C 6.4 atm D 8.8 atm E 16 atm

B 4.0 atm

Refer to the following types of chemical or physical changes. (A) Oxidation-reduction reaction (B) Brønsted-Lowry acid-base reaction (C) Sublimation (D) Dehydration (E) Precipitation Occurs when solid sodium acetate, NaC2H3O2(s), is added to water

Brønsted-Lowry acid-base reaction

Refer to the following. PCl5(g) ⇄ PCl3(g) + Cl2(g) PCl5(g) decomposes into PCl3(g) and Cl2(g) according to the equation above. A pure sample of PCl5(g) is placed in a rigid, evacuated 1.00 L container. The initial pressure of the PCl5(g) is 1.00 atm. The temperature is held constant until the PCl5(g) reaches equilibrium with its decomposition products. The figures below show the initial and equilibrium conditions of the system. Which of the following is the most likely cause for the increase in pressure observed in the container as the reaction reaches equilibrium? A A decrease in the strength of intermolecular attractions among molecules in the flask B An increase in the strength of intermolecular attractions among molecules in the flask C An increase in the number of molecules, which increases the frequency of collisions with the walls of the container D An increase in the speed of the molecules that then collide with the walls of the container with greater force

C An increase in the number of molecules, which increases the frequency of collisions with the walls of the container

Under which of the following conditions of temperature and pressure would 1.0 mol of the real gas CO2(g) behave most like an ideal gas? A Temperature (K): 100, Pressure (atm): 0.1 B Temperature(K): 100, Pressure(atm): 100 C Temperature (K): 800, Pressure (atm): 0.1 D Temperature (K): 800, Pressure (atm): 1 E Temperature (K): 800, Pressure (atm): 100

C Temperature (K): 800, Pressure (atm): 0.1

A sample of a compound that contains only the elements C, H, and N is completely burned in O2 to produce 44.0 g of CO2, 45.0 g of H2O, and some NO2 . A possible empirical formula of the compound is

CH5N

In a paper chromatography experiment, a sample of a pigment is separated into two components, X and Y, as shown in the figure above. The surface of the paper is moderately polar. What can be concluded about X and Y based on the experimental results? A X has a larger molar mass than Y does. B Y has a larger molar mass than X does. C X is more polar than Y. D Y is more polar than X.

D Y is more polar than X.

A kinetics experiment is set up to collect the gas that is generated when a sample of chalk, consisting primarily of solid CaCO3, is added to a solution of ethanoic acid, CH3COOH. The rate of reaction between CaCO3 and CH3COOH is determined by measuring the volume of gas generated at 25oC and 1 atm as a function of time. Which of the following experimental conditions is most likely to increase the rate of gas production?

Decreasing the particle size of the CaCO3 by grinding it into a fine powder

Potassium hydrogen phthalate, KHP, is used as a primary standard for determining the concentration of a solution of NaOH by titration. If the KHP has not been dried before weighing, the calculated molarity of the NaOH would be

higher than the actual value, since water is included in the apparent mass of KHP