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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
pH indicators change color at their _____. The pH at which the color change happens for a particular indicator molecule depends on its: A. pKa; concentration. B. pKa; Ka or Kb. C. equivalence point; Ka or Kb. D. equivalence point; concentration. Is the correct answer A?

CHEMISTRY
As a technician in a large pharmaceutical research firm, you need to produce 450. mL of 1.00 M a phosphate buffer solution of pH = 7.20. The pKa of H2PO4− is 7.21. You have 2.00 L of 1.00 M KH2PO4 solution and 1.50 L of 1.00 M K2HPO4 solution, as well as a carboy of pure...

Chemistry
You are required to prepare 100g of potassium nitrate crystals from its saturated solution at 75 degree Celsius. If the solubility of potassium nitrate at 75 degree Celsius is 155g and 20 degree Celsius is 31g, find the weight of potassium nitrate solution at 75 degree Celsius...

Chemistry
Given the reaction: Cu2+(aq) + S2-(aq) CuS(s) What will happen (a) if CuSO4(aq) is added? And (b) if Na2SO4(aq) is added? A. (a) Nothing; (b) Less product will form B. (a) Less product will form; (b) Nothing C. (a) Nothing; (b) More product will form D. (a) More product will ...

Chemistry
At a high temperature, the equilibrium constant for the decomposition of hydrogen iodide is 65.0. If the initial concentration of HI is 1.60 M, what is the concentration of hydrogen at equilibrium? 2Hl(g) H2(g) + I2(g) A. 1.42 M B. 0.753 M C. 0.240 M D. 0.802 M I think that ...

Chemistry
How many grams of CO2 is produced from 855 grams of C6H12O6 in the process of cell respiration?

chemistry
How many grams of FeBr 3 would be present in 150.0 mL of a 0.435 M FeBr 3 solution?

Chemistry
an empty graduated cylinder weighs 82.450g. when gilled tp 50.0 mL with a liquid it weighs 110.810g. what is the density of the liquid?

Chemistry
Which of the following has no effect on the rate ofa reaction? a)degree of branching or size of reactant molecules b)value of Heat of reaction c)presence of a catalyst d)temperature of the reactants e) concentrations of the reactants

Chemistry
For the reaction C2H4Br2+ 3KI>C2H4+2KBr+KI3, when the rate of reaction is 2.0x10^-5, what is the rate of disappearance of KI?

Chemistry
Convert a density of 13.6g/ml to lb/ft^3

Chemistry
2.36 x 10^4 s= ? days

Chemistry
The pH of your swimming pool is found to be 6.89. What is the concentration of H+ ions in the pool? A. 7.76 × 106 M B. 0.84 M C. 1.29 × 10-7 M D. 1.29 × 107 M

Chemistry
Which of the following pairs would make a good buffer? A. H2C2O4 and HC2O4- B. HNO3 and NO3- C. NaOH and NaCl D. HCl and NaOH Would it be C? I think I remember learning about these in a lesson about buffers, hence why my instinct is to go with C...

Chemistry
A solution has [OH-] = 3.5 × 10-6. Based on that, what must be true about this solution? A. It is an acidic solution. B. It is a strong base. C. It is a strong acid. D. It is a basic solution.

Chemistry
When are more products of a reaction available initially than at equilibrium? A. K = 0 B. Q < K C. Q = K D. Q > K

chemistry
A mixture of SO3,SO2 and O2 gases is maintained in 10litre flask at which the Kc for reaction is 100 . If number of moles of SO2 and SO3 are equal then how many moles of O2 present.

chemistry
calculate the number of moles and mass of methane (ch4) required to produce 11 kg of carbondoxide(co2) when combusted ?

Chemistry
assume that a drop has a volume of o.o5 ml. if a titration requires 30.00 ml for completion, what % error will each extra drop over 30 ml cause? is it 30.05-30 divided by 30 then times 100 which is equal to 0.17 %

Science Chemistry
A saturated solution of kcl is prepared at 25degree celsius. What would happen if temperature is cooled to 10degree celcius?

Chemistry
1.Name the raw materials used in the manufacture of Sodium Carbonate by Solvay process.

Inorganic Chemistry
1) Ethylene has a D2h point group. a. List every symmetry operation for ethylene. b. Write a transformation matrix for each operation and describe the effect that each operation has on the molecule’s coordinates in (x,y,z) Thank you!

chemistry
For a deep descent,a scuba diver uses of helium and oxygen with a total pressure of 8.00 atm. If the oxygen has a partial pressure of 1200 mmHg , what is the partial pressure of the helium?

chemistry
1.000 g of bronze was dissolved in the mixture of acids. The solution was transferred into 100 ml volumetric flask and filled to the mark. 10 ml aliquote of this solution was transferred into another 100 ml flask and diluted to the mark. 10 ml of the resulting solution was ...

Chemistry
CHCl3 + MnO4- = Cl2 + CO2 + Mn+2 Balance the above with half reactions in acidic medium. For the above reaction, can you please show the half reactions...which is getting oxidised...both C and Cl's oxidation # are changing showing both getting oxidised,.how is this possible? ...

Chemistry
What are the other two independent other than concentration for reaction of hydrochloric acid with calcium carbonates. And what are thier control variable?

value chemistry
observation made when chlorine is bubbled through sodium iodide

chemistry
Describe how would accurately prepare one litre of 150 ppm using copper

Chemistry
MgCl2 (aq) → Mg+2(s) + 2Cl-(g) are the states right? or would Mg+2 be a (g). Note: MgCl2 is very soluble. thanks

Chemistry
When coal is mined, it is tested for how much heat it can produce when it burns. A 1.245g sample of coal was placed into a calorimeter containing 2000.0 mLs of water at 17.5 degrees Celsius. After the coal was combusted in the calorimeter, the water's temperature was found to ...

Chemistry
The toxic metal cadmium Cd2+ has a tendency to complex with as many as 4 Cl- ions. The complexation reactions can be written as: Cd2+ + Cl- ---> CdCl+ ``````` log Kf,1 = 1.98 Cd2+ + 2Cl- ---> CdCl20 `````` log Kf,2 =2.60 Cd2+ + 3Cl- ---> CdCl3- `````` log Kf,3 = 2.40 ...

Chemistry G.12
(a) Which of the properties, crystal lattice energy and hydration energy, reduces the solubility of an ionic compound? (b) Which property, when increased, increases the solubility? I was thinking for (a) that it would be crystal lattice energy and for (b) hydration... Im not ...

Chemistry
If 0.250 L of aqueous solution with a density of 1.00 g/mL contains 13.7 g of pesticide, express the concentration of pesticide in (a) ppm and (b) ppb.

CHEMISTRY
BALANCE THE REDOX REACTION USING HALF CELL METHOD IN AN ACIDIC MEDIUM CHCl3 + MnO4- = Cl2 + CO2 + Mn+2

Chemistry
Half reaction method of balancing redox reaction CHCl3 + MnO4- = Cl2 + CO2 + Mn+2

ap chemistry
Which of the following statements about the pH scale is not true? A. In a pH expression, the hydronium ions, H3O+, can be abbreviated simply as H+. B. A solution with a pH of 4 has twice the [H+] of a solution with a pH of 2. C. The pH scale is based on a scale involving ...

ap chemistry
When are more products of a reaction available initially than at equilibrium? A. K = 0 B. Q < K C. Q = K D. Q > K

chemistry -3.2.4
Given the reaction: Cu2+(aq) + S2-(aq) CuS(s) What will happen (a) if CuSO4(aq) is added? And (b) if Na2SO4(aq) is added? A. (a) Nothing; (b) Less product will form B. (a) Less product will form; (b) Nothing C. (a) Nothing; (b) More product will form D. (a) More product will ...

chemistry - 3.1.6
At a high temperature, the equilibrium constant for the decomposition of hydrogen iodide is 65.0. If the initial concentration of HI is 1.60 M, what is the concentration of hydrogen at equilibrium? 2Hl(g) H2(g) + I2(g) A. 1.42 M B. 0.753 M C. 0.240 M D. 0.802 M I'm actually ...

Chemistry
A 0.2512 stock sample of HCl is tirade to equivalence . If 16.77ml of 0.1410 M NaOH is required to reach the equivalence point, what volume of stock HCl was used for the tritation?

chemistry - 4.1.4
The [OH-] ion concentration of a sample is 1 × 10-10 M. What is the concentration of [H+] in the sample at 25°C? A. 1 × 10-14 M B. 1 × 10-4 M C. 1 × 10-10 M D. 1 × 10-6 M I think the answer is C. is this correct?

chemistry
The problem is as follows: The toxic metal cadmium Cd2+ has a tendency to complex with as many as 4 Cl- ions. The complexation reactions can be written as: Cd2+ + Cl- ---> CdCl+ log Kf,1 = 1.98 Cd2+ + 2Cl- ---> CdCl2^0 log Kf,2 =2.60 Cd2+ + 3Cl- ---> CdCl3- log Kf,3...

chemistry
What is a neutralization reaction? A. A reaction that involves neutral reactants B. A reaction in which the reactants are a salt and water C. A reaction in which the product is either acidic or basic D. A reaction that removes essentially all H+ and OH- I know that it isn't A ...

chemistry
If the equilibrium constant is much less than 1, what can you conclude about the concentrations of the reactants and products? A. Reactants are in the numerator of the equilibrium expression, so the concentration of the reactants is high. B. Products are in the numerator of ...

chemistry
How can you shift the equilibrium of the reaction between hydrogen and chlorine toward the products? H2(g) + Cl2(g) --> 2HCl(g) A. Add Cl2. B. Remove H2. C. Increase the pressure. D. Add HCl. would the answer to this one be to add Cl2? so answer A?

chemistry
Given the reaction: Cu2+(aq) + S2-(aq) CuS(s) What will happen (a) if CuSO4(aq) is added? And (b) if Na2SO4(aq) is added? A. (a) Nothing; (b) Less product will form B. (a) Less product will form; (b) Nothing C. (a) Nothing; (b) More product will form D. (a) More product will ...

chemistry
The equilibrium constant for the formation of phosphorus pentachloride is 1.9. If the partial pressure of each gas is 0.5 atm, will the reaction (as written) proceed forward or backward to reach equilibrium? PCl3(g) + Cl2(g) PCl5(g) A. Backward, because K is greater than Q B. ...

chemistry
What effect does raising the temperature of the reaction chamber at a constant pressure have on the following reaction at equilibrium? 2NO2(g) N2O4(g) + heat A. The equilibrium shifts toward the reactants because the reverse reaction is endothermic. B. The concentration of NO2...

Chemistry
covert Joules/Kevin to (atm)(nm^3)/(K) I have done this so far. J*[1L atm]/[101.33J]*[(.001m)^3]/[1L]*[10^9n]/​[1m] Thank you

Chemistry
When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 26.4 g of carbon were burned in the presence of 82.1 g of oxygen, 11.7 g of oxygen remained unreacted. What mass of carbon dioxide was produced? Express your answer to one decimal place and ...

chemistry
Why does the density of gas in a hot air balloon decrease as the gas is heated? A. The mass of gas decreases as temperature increases. B. The mass of gas increases as temperature increases. C. The volume of gas decreases as temperature increases. D. The volume of gas increases...

AP Chemistry
If the pH of a nitric acid solution is 2.34, then what is the molarity of nitric acid in the solution? A. 1.6 × 10-4 M B. 3.8 × 10-3 M C. 2.2 × 10-2 M D. 4.6 × 10-3 M

AP Chemistry
What should be the range for the exponent of [H+] in solutions that are characterized as acidic? A. 0 to -0.07 B. 0 to 0.7 C. 0 to -7 D. 0 to 7

ap chemistry
What is the [H3O+] of a solution with [OH-] = 6.3 × 10-4 M? A. 6.3 × 10-18 M B. 10.80 M C. 6.3 × 10-4 M D. 1.6 × 10-11 M DrBob222 can you help me with this question please?

chemistry
What is the chemical equation that describes the complete neutralization of H3PO4 by NaOH? A. H3PO4 + 2NaOH Na2HPO4 + 2H2O B. H3PO4 + H2O H2PO4- + H3O+ C. H3PO4 + NaOH NaH2PO4 + H2O D. H3PO4 + 3NaOH Na3PO4 + 3H2O

chemistry
Which of the following is true about the results of a neutralization reaction? A. An acid and a base form water and salt. B. Water reacts with a base to form the hydroxide ion. C. Water reacts with an acid to form the hydronium ion. D. An acid and a base dissociate into their ...

chemistry
Knowing what information would allow you to order gas molecules according to their velocity? A. Pressure and temperature B. Volume and molecular mass C. Pressure and volume D. Temperature and molecular mass

chemistry
How does table salt (NaCl) dissolve in water? A. Water molecules hydrogen bond with sodium ions and chloride ions. B. Each sodium ion is surrounded by chloride ions. C. Each NaCl molecule is surrounded by water molecules. D. The oxygen atoms in water molecules attract sodium ...

chemistry
When we are calculating the molality of KNO3 in H2O do we add i the van hoff factor

chemistry
At what Celsius temperature will the numerical reading on the Fahrenheit thermometer be 44 degress less than that on the Celsius thermometer?

Chemistry
How much energy is needed as heat at a pressure of 1 ATM when 78g of liquid ethanol (C2H5-OH) at 298 K is converted to solid enthalpy at 159 K (FP). The molar enthalpy fusion is -277.6 KJ/Mole, and heat capacity of liquid ethanol is 112.3 J/mole k.

chemistry
how many moles of NH3 does it take to make 8.0 mol of H20 according to the reaction shown below? 4NH3 + 5O2 --> 4NO + 6H2O I REALLY NEED HELP WITH THIS AS I AM LOST. PLEASE PROVIDE NOTES.

Chemistry
At constant pressure, which of these systems do work on the surroundings? A(s)+B(s)-->C(g) 2A(g)+2B(g)--> 3C(g) A(g)+B(g)-->3C(g) 2A(g)+3B(g)-->4C(g) I've tried everything and I just don't understand what I'm doing wrong.

Chemistry
Estimate the orders and rate constant K from the results observed for the Reaction. What is the rate when [H2O2]=[I-]=[H+]=1.0M? H2O2 + 3I- + 2H+ →I3- + 2H2O Experiment H2O2 [I-] [H+] Initial rate MS-1 1 0.010 0.010 0.0050 1.15e-6 2 0.020 0.010 0.0050 2.30e-6 3 0.010 0....

Chemistry
When ice melts, it absorbs 0.33 kJ per gram. How much ice is required to cool a 13.0 oz drink from 71 ∘F to 39 ∘F, if the heat capacity of the drink is 4.18 J/g∘C? (Assume that the heat transfer is 100 % efficient.)

Chemistry
Which of the following will contain more atoms: 12g of carbon or 12g of magnesium? Give a reason for your answer. Thanks

chemistry
Arrange given metal in decreasing order of electrical conductivity ( Al ,Ag ,Hg ,K,Ca

Chemistry
A chemist wants to make 500.0 mL of 0.215M NaCl. What mass of NaCl is needed? would it be .500 L x .215 M = .1075 mol NaCl .1075 mol x 58.44g NaCl = 6.28g NaCl needed

Chemistry
What volume of 12.1M HCl(aq) is required to make 435 mL of 0.100M HCl? would i just follow the equation V1xM1=V2M2 V1x12.1=.435Lx.100M = 0.00360 L

chemistry
Silver chloride (AgCl) is a white solid. For the equilibrium reaction AgCl(s) = Ag+(aq) + Cl‐(aq) The Ksp for AgCl = 1.6 * 10‐10. At equilibrium, would you expect to have more silver and chloride ions or more solid silver chloride?

biological chemistry
How many calories of heat are needed to increase the temperature of 55 g of ethanol from 18 Celsius to 48 Celsius

chemistry 102
what will happen if copper is overheated during the drying process? How will this affect the percent recovery?

chemistry
In an electrolytic solution the density of CuSO4 decreases or increases or remains constant?

chemistry
Which is most acidic in its aqueous solution? a)FeCl3 b)AlCl3 c)NiCl3 d)BeCl2

chemistry
on heating 25g of a saturated solution to dryness at 60c,4g of anhydrous salt was recovered.calculate it's solubility in grammes per 100g of solvent

chemistry
When are more products of a reaction available initially than at equilibrium? A. K = 0 B. Q < K C. Q = K D. Q > K

chemistry
Given the following solubility constants, which list arranges the solutes in order of increasing solubility? CaCO3: Ksp = 2.8 × 10-9 Ca(OH)2: Ksp = 5.5 × 10-6 CaSO4: Ksp = 9.1 × 10-6 CaF2: Ksp = 5.3 × 10-9 A. CaSO4 < Ca(OH)2 < CaCO3 < CaF2 B. CaSO4 < Ca(OH)2 &...

chemistry
Given the equilibrium concentrations in the table, what is the equilibrium constant for the synthesis of ammonia at this temperature? 3H2(g) + N2 2NH3(g) A. 0.0035 B. 0.014 C. 0.066 D. 0.017

chemistry
What change do you expect if the value of the reaction quotient is greater than the value of the equilibrium constant? A. The rate of the forward reaction is greater than the rate of the reverse reaction. More reactant forms. B. The rate of the forward reaction is greater than...

chemistry
Which of the following is true about the results of a neutralization reaction? A. An acid and a base form water and salt. B. Water reacts with a base to form the hydroxide ion. C. Water reacts with an acid to form the hydronium ion. D. An acid and a base dissociate into their ...

chemistry
What does a buffer do? A. It resists a change in pH when H+ or OH- is added to a solution. B. It prevents an acid-base reaction from happening. C. It prevents an acid or base from being neutralized. D. It prevents a salt from forming in solution.

chemistry
Why is HCl required in the stomach? A. To transport proteins into the small intestines B. To help absorb other acids in the stomach C. To catalyze the digestion of carbohydrates D. To aid in the digestion of proteins

chemistry
The [OH-] ion concentration of a sample is 1 × 10-10 M. What is the concentration of [H+] in the sample at 25°C? A. 1 × 10-14 M B. 1 × 10-4 M C. 1 × 10-10 M D. 1 × 10-6 M

chemistry
Which of the following chemical reactions represents a neutralization reaction? A. CH4 + 2O2 CO2 + H2O B. HCl + NaOH H2O + NaCl C. NH3 + H2O NH4++ OH- D. CH3COOH + H2O CH3COO- + H3O+

Chemistry
When 1.5 grams of salt are added to 12.0 grams of water and the salt dissolves, what is the mass of the system?

Chemistry
Sodium + Sulfuric Acid and Phosphoric Acid + Magnesium Hydroxide a.write the formula b. supply the product c.type of reaction d. balancing

chemistry
Okay so i have this titration question and I don't really know the steps because everyone explains it differently. IF someone could explain me the steps of how i could solve this questions and other like this. Thanks In three runs of titration 22.8mL, 221.mL, 22.2mL of 0.200 ...

Chemistry
home / study / science / chemistry / questions and answers / a subtilisin with an active site mutation of his ... Question: A subtilisin with an active site mutation of His t... EDIT QUESTION A subtilisin with an active site mutation of His to Ala had a substantially decreased...

Chemistry
A rectangular solid of unknown density is 6cm long, 3cm high, and 7cm wide. The mass of this solid is 250g. Calculate the density.

Chemistry
An enzyme has velocities of 0.11 nmol/min at a substrate concentration of 1 μM, 0.34 nmol/min at a substrate concentration of 5 μM, and 0.45 nmol/min at a substrate concentration of 10 μM. What is the Vmax for the enzyme if the KM is 5 × 10–6 M? A. 0.22 nmol/...

chemistry
At 1 atm, how much energy is required to heat 51.0 g of H2O(s) at –16.0 °C to H2O(g) at 125.0 °C?

chemistry
Which of the following is true about the results of a neutralization reaction? A. An acid and a base form water and salt. B. Water reacts with a base to form the hydroxide ion. C. Water reacts with an acid to form the hydronium ion. D. An acid and a base dissociate into their ...

chemistry
What is the general form for the simplest type of acid-base reaction? A. acid + base salt + water B. acid + base base + acid C. acid + base H+ + OH- D. acid + base solid + water

chemistry
A, B, C, and D are 4 salts whose Ksp values are 9.21 × 10-8, 7.44 × 10-11, 1.07 × 10-21, and 38.65, respectively. What is the correct arrangement of their solubilities in decreasing order? A. D, A, B, C B. C, B, A, D C. A, B, D, C D. C, B, D, A

chemistry
Acetic acid is known to be a weak acid. What will happen to the acidity of the solution when sodium acetate is added to acetic acid? A. The solution will become more acidic. B. The pH will remain the same. C. The solution will become less acidic. D. The solution will become ...

chemistry
Which of the following bases could you write an equilibrium expression for? A. Ba(OH)2 B. KOH C. NaOH D. NH3

chemistry
During a chemical reaction, if Q = K, what can be said about the reaction? A. The reaction still proceeds in both directions, but the net result is that the reactant and product concentrations do not change. B. The amount of product is always equal to the amount of reactant. C...

chemistry
Which of the following is true of the solubility product constant? A. It is the product of the initial concentrations of the ions in a solution. B. It is an equilibrium constant. C. It is an equilibrium position. D. Its value changes in the presence of a common ion. Hi, I know...

chemistry
Which equation would describe the following equilibrium constant? Kc = [Bi3+]2[S2-]3 A. Bi2S3(s) + 6HCl(aq) 2BiCl3(aq) + 3H2S(aq) B. Bi2S3(s) 3Bi2+(aq) + 2S3-(aq) C. BiS(s) Bi3+(aq) + S2-(aq) D. Bi2S3(s) 2Bi3+(aq) + 3S2-(aq)

chemistry
What happens to the following reaction at equilibrium if the pressure is decreased? 2H2(g) + O2(g) 2H2O(g) A. The equilibrium shifts left because Q < K. B. The equilibrium shifts right because Q < K. C. The equilibrium shifts right because Q > K. D. The equilibrium ...

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