# Chemistry

Popular questions and responses by Chemistry
1. ## Enthalpy

Consider the following reaction: 2 Mg + O2 → 2 MgO ΔH rxn = -1203 kJ Calculate the amount of heat (in kJ) associated with complete reaction of 4 moles of Mg. How do I set this up correctly?

2. ## chemistry

Consider a system consisting of a cylinder with a movable piston containing 10^6 gas molecules at 298K at a volume of 1L. Consider the following descriptions of this system: 1. Initial system 2. Starting from the initial system, the volume of the container

3. ## Lauren

Write the electron configuration of Sn and Sn2+ Give the electron configuration of Cu+ and Cu2+

4. ## Lauren

Which of the following has a standard enthalpy of formation value of zero at 25 degrees C and 1.0 atm A. Fe(s) B. Fe2O3(s) C. FeSO4(s) D. FeSO4(aq) E. FeS3(s) and what is enthalpy or how do you find it

5. ## chemistry

What is the lattice energy of NaBr? heat of formation of NaBr = -362 kJ/mol heat of sublimation for Na = 107.30 kJ/mol ionization energy for Na = 496 kJ/mol bond dissociation energy for Br2 = 190 kJ/mol electron affinity of Br = -325 kJ/mol heat of

6. ## Equilibrium

An equilibrium mixture of the following reaction was found to have [I2]= 0.0325M at 1200 ∘C. What is the concentration of I ? I2(g)⇌2I(g) Keq= 1.5×10−2 at 1200 ∘C Someone please help set this up?

7. ## chemistry

AlPO4(s)Al^3+(aq)+PO4^3-(aq) PO4^3-(aq)+H3O^+(aq)HPO4^2-(aq)+H2O(l) What is the net ionic equation for AlPO4(s) dissolving in H3O^+(aq)?

8. ## Chem

Hypobromous acid,HOBr, has acid -ionization constant of 2.5 X 10^-9 at 25 Celsius . What is the pOH of a 0.63 M HOBr solution? A4.40 B3.87 C5.20 D9.60 E10.13 I'm getting two answers between A or B

9. ## Molarity

A 4.0−L sample of a 6.3M NaCl solution is diluted to 50L . What is the molarity of the diluted solution? How would I set this up?

10. ## Science

2.40g of copper (ii)tetraoxosulphate(iv) crystals are prepared from 0.45g of copper (ii) oxide.the copper (ii) tetraoxosulphate(vi) crystals contain 0.45g of water of crystallisation.what mass of crystals and what is the mass of water of crystallisation

11. ## Chemistry

For preparing a set of standard solutions of FeNCS2+, the equilibrium molar concentration of FeNCS2+ is assumed to equal the initial molar concentration of the (SCN-) in the reaction mixture. why is this assumption valid?

12. ## chemistry

A 79.9-L sample of a gaseous hydrocarbon, measured at 1.00 atm pressure and 25.0°C, is burned in excess oxygen, liberating 4.24 × 10^3 kJ of heat at constant pressure. What is the identity of the hydrocarbon? (R = 0.0821 L · atm/(K · mol)) Substance

13. ## Chemistry

How many grams of sucrose are needed to make 875 mL of a 39.0% (w/v) sucrose solution?

14. ## Carson

What is the molecular geometry shape for H2GeO and is Sel2 polar or non polar. Thanks

15. ## How many mole are there in 30g of calciumm chlorid

How many mole are there in calcium chloride, CaCl2 (CaCl2=111).

16. ## Chemistry

Calculate the number of grams of xenon in 3.566 g of the compound xenon tetrafluoride.

17. ## chem

Excess fluorine, F2(g), reacts at 150°C with bromine, Br2(g), to give a compound BrFn. If 423 mL Br2(g) at 150°C and 748 mmHg produced 4.20 g BrFn, what is n? Predict the shape of this molecule using the VSEPR model.

18. ## Freezing solution

An ethylene glycol solution contains 26.2g of ethylene glycol (C2H6O2) in 81.4mL of water. Calculate the freezing point of the solution. (Assume a density of 1.00 g/mL for water.) how do I set this up?

19. ## Chem

in a 0.01 M solution of 1.4 butanedicarboxylic acid, (Ka1=2.9x10^-5, Ka2=5.3x10^-6), which species is present in the lowest concentration?

20. ## Chemistry

Ammonia has the formula NH3. Household ammonia is a dilute aqueous solution of NH3 . Aqueous ammonia is a base that can neutralize acids. If 18.4mL of 0.800 M HCl solution are needed to neutralize 5.00 mL of a household ammonia solution, what is the molar

21. ## Lauren

Use Lewis symbols to represent the electron transfer between the following atoms to give ions with noble gas configuations: A. Mg and S B. Ba and I

22. ## mass

A hard water sample contains 0.0081 %Ca by mass (in the form of Ca2+ ions)What mass of water in grams contains 1.3g of Ca? (1.3g of Ca is the recommended daily allowance of calcium for 19- to 24-year-olds.) Need help set this up?

23. ## chemistry

Alexandra decides to climb Mt. Krumpett, which is 5000 high. She determines that this will require a total of 3600 of energy for the trip. For her food supply, she decides to take nutrition bars. The label states that each bar contains 50 of carbohydrates,

24. ## Chemistry

The average human body contains 5.30L of blood with a Fe2+ concentration of 2.30×10−5M . If a person ingests 11.0mL of 15.0mM NaCN , what percentage of iron(II) in the blood would be sequestered by the cyanide ion?

25. ## science

ammonia is produced from the reaction of nitrogen and hydrogen according to the following balanced equation. N2+3H2g----- > 2NH3g. what is the maximum mass that can be produced from a mixture of 2.00×10³gN and 8.00×10⁴H2?

26. ## Chem

What is the equilibrium concentration of chloroacetic acid in a solution prepared by dissolving 0.0314 mil of chloroacetic acid in 1.10L of water? For chloroacetic acid, Ka= 1.4X10^-3

27. ## science

the teacher instructed three students A,B,and C respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). 'A' dissolved 50 g of NaOH in 100 ml of water B dissolved 50g of NaOH in 100g of water while C dissolved 50g of NaOH in

28. ## Chemistry

Given the equation C3H8+5O2->3CO2+4H2O. 1.)Suppose 1.5 moles of C3H8 will be used, How many moles of H2O and CO2 will be formed? 2.)what volumes (at STP) of O2 and CO2 are involved?

29. ## Heat

Consider the following equation: CO + 2 H2 → CH3OH ΔH rxn = -128 kJ Calculate the amount of heat (in kJ) associated with complete reaction of 8.08 g H2. How would u set that up?

30. ## Chemistry

Calculate the formula mass for each of the following halogen compounds to five or more significant figures:? bake asked 5 months ago (a) NaIO3 (antiseptic) (b) CCl2F2 (former refrigerant)

31. ## Abby

If you have 320.0 mL of water at 25.00 °C and add 140.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

32. ## Chemistry

Calculate DeltaHrxn for the following reaction: C + H2O --> CO + H2 Use the following: C + O2 --> CO2 DeltaH = -393.5 kJ 2CO + O2 --> 2CO2 DeltaH = -566.0 kJ 2H2 + O2 --> 2H2O Delta H = -483.6 kJ DeltaHrxn = ?

33. ## chemistry

CH3 CH3-C-CH3 CH3CH2CH2-C-CH2CH2CH2CH3 CH3 give the IUPAc name for this compound? is it 4-methyl-4-tert-methyloctane?

35. ## Chemistry

Vitamin B12, cyanocobalamin, is essential for human nutrition. It is concentrated in animal tissue but not in higher plants. Although nutritional requirements for the vitamin are quite low, people who abstain completely from animal products may develop a

36. ## Sara

How many mL of .200M acetic acid are mixed with 13.2mL of.200M sodium acetqte to give a buffer with pH=4.2

37. ## Jake

If 142.38 g of l water at 21.7 degrees C is placed into a syrofoam cup with 174.36 g of ice at -27.5 degrees C what would be the final temperature of the entire contents at equilibrium? If it is partially frozen, how many g of the ice has melted? given

38. ## Chemistry

A certain mine produces 2.5 108 kg of copper from chalcopyrite (CuFeS2) each year. The ore contains only 0.80% Cu by mass. (a) If the density of the ore is 2.0 g/cm3, calculate the volume of ore removed each year. (b) Calculate the mass of SO2 produced by

39. ## Chemistry

1.) For the reaction: 2 HBr + H2SO4 --> Br2 + SO2 + 2 H2O : if you start with 5.00 g of each reactant and end up with 5.00 g of bromine, what is the percent yield? 98.8% 2.0% 101.2% 100.0% 2.) For the reaction: 2 HBr + H2SO4 --> Br2 + SO2 + 2 H2O : if you

40. ## ryancon

The half-life of rubidium-87 (natural absorbance 27.83%) is 5.1x10^11 years. What mass of rubidium is present if an average sample decay rate of 35.0 disint./sec is detected? I've already converted years to seconds but not sure what to do after..

41. ## science

how many grams of nacl are required to neutralize 100 ml of 1M h2so4???

42. ## Chemistry

NaCl [Symbol] Na + Cl2 Type of reaction: synthesis KOH + HNO3 [Symbol] HOH + KNO3 Type of reaction: double replacement Ca + S [Symbol] CaS Type of reaction: synthesis BaBr2 + Cl2 [Symbol] BaCl2 + Br2 Type of reaction: Cs2 + H2O [Symbol] CsOH + H2 Type of

43. ## May

Based on the data in this table, what would be the value of k at 795 K? T k 625 1.1 x 10^-4 635 1.5 x 10^-4 645 2.0 x 10^-4 I tried to figure it out using two different ways, and I got 7.3 x 10^-3 both times. I asked for a "hint" and the homework site told

44. ## Equilibrium constant

Consider the reaction: SO2Cl2(g)⇌SO2(g)+Cl2(g) A solution is made containing initial [SO2Cl2]= 0.022M . At equilibrium, [Cl2]= 1.7×10−2M Calculate the value of the equilibrium constant.

45. ## pressure

What is the pressure in millimeters of mercury of 0.0140mol of helium gas with a volume of 222mL at a temperature of 30∘C?

46. ## Pressure

Aerosol cans carry clear warnings against incineration because of the high pressures that can develop upon heating. Suppose a can contains a residual amount of gas at a pressure of 750mmHg and a temperature of 23∘C. What would the pressure be if the can

47. ## Freezing point

How many moles of each of the following are needed to give the same freezing point lowering as 5.0mol of the nonelectrolyte ethylene glycol in 1 kg of water?CH3−OH, a non electrolyte, KNO3, a strong electrolyte. Im confused on what they are asking, and

48. ## Metals

Transition metals (also called heavy metals) form insoluble compounds with hydroxide ions. Therefore, it is possible to extract heavy metal ions from water by raising the pH. The precipitation reaction between cadmium(II) and hydroxide is shown below.

49. ## Chemical Reactions

How can i get the step by step procedure for a chemical reaction? For example: the step by step procedure for the synthesis reaction of ammonia

50. ## Chemistry

A sample of toluene, C7H8 has a mass of 74.5 g. a) how many molecules does the sample contain? b) How many carbon atoms does it contain? How many hydrogen atoms does it contain? My work For b would it be 7 carbon atoms and 8 hydrogen atoms

51. ## CHEMISTRY

Method for getting correct answer? Thank you! The reaction below is an endothermic reaction. What would one have to do to shift the equilibrium to the right? SO2Cl2(g)↔SO2(g) + Cl2(g) a. Decrease the temperature b. Increase the temperature c. Remove some

52. ## Chemistry

Electron exhibiting a particle wavelength of 5.2 x 10-9 are emitted from hydrogen atoms after interaction with high energy photons. Assuming that the electrons in the hydrogen atom were in their ground state prior to interaction, determine the wavelength

53. ## Idontgetit

The value of the equilibrium constant, Kc, at a certain temperature is 8.33 x 10-4. Would the reaction as represented by the chemical equation favor reactants or products? Enter P or R. Cl2CO(g) = CO(g)+Cl2(g)

54. ## Idontgetit

The value of the equilibrium constant, Kc, at a certain temperature is 2.56 x 10-1. If the reaction quotient for a mixture of these species at the same temperature is found to be 9.90 x 10-4, would the mixture yield more products, more reactants or is it

55. ## Idontgetit

The value of the equilibrium constant, Kc, at a certain temperature is 2.50 x 102. If the reaction quotient for a mixture of these species at the same temperature is found to be 7.37 x 100, would the mixture yield more products, more reactants or is it at

56. ## Idontgetit

The value of the equilibrium constant, Kc, at a certain temperature is 2.56 x 10-1. If the reaction quotient for a mixture of these species at the same temperature is found to be 9.90 x 10-4, would the mixture yield more products, more reactants or is it

57. ## Chemistry

the hydronium ion concentration of a 0.050 M solution of a weak acid is 5.9 X 10^-3 M. the acid-dissociation constant is 1.37 X 10^-4 at 25 celsius. what is the pH of this solution? A. 0.077 B. 1.30 C. 2.23 D. 3.86 E. 5.13

58. ## Chemistry

A solution of AuCl- is mixed with a solution of Sn2+ under standard conditions. What is the equation? the answer is 2AuCl4- + 3Sn2+ -> 3Sn4+ + 2Au + 8Cl- how do i get this? ITS desperate... plz help me! THANK_YOU SO MUCH!

59. ## Chemistry

What volume of 0.250M KOH is required to titrate 2.30 x 10^3 mol of the weak acid H2C2O4 ? I know the answer is 18.4, but can you show the process?

60. ## chemhelp

is LiCl toxic?

61. ## Shawn

How many milliliters of 0.355 M NaF solution are needed to react completely with 24.6 mL of 0.216 M CaCl2 solution? How many grams of CaF2 will be formed? The reaction is CaCl2(aq) + 2NaF(aq) → CaF2(s) + 2NaCl(aq)

62. ## CHEM

What is the number of "UNBOUND" electrons in H2O...its not 0 or 2....is it 1??

63. ## kassie

What is the major product of the reaction between methanol and (2R,3S)-2-bromo-3-methylpentane at room temperature?

64. ## chemistry

Given the reaction 3C(s) + 4H2(g) + 5O2(g) ---> 3CO2(g) + 4H2O(l) ÄH= -2323.7 kJ How much heat would be released when 34.1 g of H2 react?

65. ## muah

using only words and no numbers how would i explain the steps necesarry to show how many kilograms are in a milligram? thanks :D

66. ## muah

explain why the name of the insect millipede doesnt follow SI conventions? please help me i cant find this any where in my text. I would be very happy if you did help. :D

67. ## chemistry

The reaction converting glycerol to glycerol-3-phosphate is energetically unfavorable by 9.2kJ. The reaction of ATP with water to yield ADP, hydrogen phosphate ion, and hydrogen ion is energetically favorable by 30.5kJ. These reactions are coupled so that

68. ## REETA

A 2.10 mol sample of oxygen gas is confined to a 5.10 L vessel at a pressure of 7.99 atm. Find the average translational kinetic energy of an oxygen molecule under these conditions in (j/mol) When i was working this out i tried using pv=nrt to find the

69. ## Lauren

The specific heat of water is at 4.184J/g * degree C. How much heat is evolved, or absorbed, when the temperature of 9.00 mol of liquid water cools from 38 degrees C to 28 degrees C? How do I start this problem

70. ## Suzy

Can some one read my lab report for me... I have it almost finished.. I just need help on the discussion part Please

71. ## Jake

A combustion bomb containing 5.417 g of aluminum metal and 15.974 g of iron III oxide is placed in an ice calorimeter that initially contained 7.746 kg of ice (at o degrees C) and 7.894 kg of liquid water (at o degrees C). The reaction, once ignited by

72. ## Jim

I need some help with calculating percent yield and percent purity of aspirin. Here's my data (questions follow): SYNTHESIS Mass of salicylic acid.., 2.0 g Volume of acetic anhydride.., 5 mL Mass of watch glass.., 22.10 g Mass of aspirin and watch glass..,

73. ## chemistry

what would be the e configuration for sodium- 23 (up and down arrows) 1s- ? arrows 2s- ? arrows 2p- ? arrows 3s- ? arrows 3p- ? arrows

74. ## chemistry

How much heat is required to take 4 kg of water from 20◦C to near boiling at 99◦C? Answer in units of J. I got 1320.88?

75. ## Science

What is the balance equation of decane

76. ## Science

Ammonia is produced from the reaction of nitrogen to the following balanced equation N2+3H2-2NH3

77. ## science

1:when 20.0ml of 1.7m AgN03 added to grammar of AgCL will be produced? 2:if the percentage yield is 30%,calculate the actual yield.

78. ## chemistry

what is the source of activation energy in an exothermic reaction? Is an example heat?

79. ## Chemistry

The molecules present in 5.2gms of glucose will be c6h12o6

80. ## PLZZZ HELP

Heat of Combustion of paraffin wax Initial mass of candle 40.3g Mass of tin calorimeter 41.1g Mass of half-filled calorimeter with water 220.4g Initial temp of water 18.8°C Final temp of water 26.6°C Final mass of candle 38.2g Calculate heat of

81. ## Chemistry

How to prepare 10% sucrose solution enriched with 0.1% phenylalanine? And also how to make the stock solution of phenylalanine for the above process. I have prepared 10% sucrose solution by adding 10g sucrose in 100ml water , but how do i make 0.1%

82. ## Chemistry

Neutralization of water containing H2SO4 and HNO3 with CaSO3. What is the pH in water if the volume is 1000 liter and the concentration of H2SO4 is 0,0013 M and concentration of H2SO4 is 0,0010 M ? And how much of CaCO3 is needed for neutralization of the

83. ## chemistry

CH3-C(triple bond)C-CH-(C2H5)CH3product a and product b

84. ## chemistry

CH3-C(triple bond)C-CH-C2H5-CH3product a and product b

85. ## Science

Calculate the gram molecular mass of nitrogen if 360cc at STP weigh 0.45g.

86. ## Chemistry

Why was etching needed to bring out the grain boundaries? My answer: Is it for the light to bounce back?

87. ## Chemistry 12th

How can you prepared to benzo phenol from phenyl magnetium bromide

88. ## Kris

A gas mixture containing 0.400 mol He, 0.184 mol CH4 and 0.0374 mol Ne was placed in a 3.00-L flask at 301 K. What is the PRESSURE (atm) in the flask?

89. ## HOFBrINCl

can someone help me on these 2 questions so i can get an idea to do the rest of mine. im given hydrochloric acid and a marble chip (calcium carbonate i think), so what would be the reactants, the word equation, the balanced equation, prediction of type of

90. ## for solubility

How match water make in 0.123 N NaoH for 0.1 N NaoH

91. ## georgia

what is a solubility rate?

92. ## caley

A solution contains 2.0 × 10^–3 M Ba^2+ and 1.0 × 10^–2 M Sc^3+. A source of F^– is slowly added to the solution. Will BaF2 (Ksp = 1.84 × 10^–7) or ScF3 (Ksp = 5.81 × 10^–24) precipitate first? I believe that ScF3 would precipitate first but

93. ## Volume

Imagine that you have an ideal gas in a 7.00L container, and that 1050 molecules of this gas collide with a square-inch area of the container at any given instant. If the volume is increased to 56.0L at constant temperature, how many collisions will occur

94. ## Molar mass

A sample of gas has a mass of 0.580g . Its volume is 119mL at a temperature of 80∘C and a pressure of 743mmHg . Find the molar mass of the gas. I think I got a step wrong in the problem, please help?

95. ## Moles

How many moles of each of the following are needed to give the same freezing point lowering as 5.0mol of the nonelectrolyte ethylene glycol in 1 kg of waterCH3−OH, a non electrolyte,KNO3, a strong electrolyte I am so lost with what they exactly want for

96. ## Molarity

A 44.8−mL sample of a 7.0M KNO3 solution is diluted to 1.10L What volume of the diluted solution contains 16.0g of KNO3? Would I do the same thing for this one or would does it have an extra step it it.

97. ## newsome

1. lactate has a molecular weight of 90.08. How much lactate is needed to make 3 liters of .15 molar lactate. 2.What is the percentage of lactate (it's a solid) in the solution made in question 1.

1. Spectroscopic studies of the reaction of azide ion with the cluster [Ru3(CO)12] in acetone solvent confirmed the occurrence of process (i) under a CO atmosphere. Kinetic measurements of this rapid [Ru3(CO)12]+ N3– →[Ru3(NCO)(CO)11]–+ N2(i)

99. ## Chemistry

Calculate the volume of 2.00 M solution of KOH that is required to neutralize 30.0 mL of 1.00 M solution of HNO3.