# Can someone please help me out here? I've tried several times and i keep getting the wrong answer :( lol A small crucible is filled with 100.00 mL of n-hexadecane (MW (226.44 g/mol), density (0.7703 g/mL)) and 2.10 L of

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1. ## Chemistry

Can someone please help me out here? I've tried several times and i keep getting the wrong answer :( lol A small crucible is filled with 100.00 mL of n-hexadecane (MW (226.44 g/mol), density (0.7703 g/mL)) and 2.10 L of 7-octenyltrichlorosilane (MW (245.65
2. ## Chem

I'm pretty sure this should be a fairly simple conversion factor problem, but I'm getting bad results. I want to go from molarity (mol/L) to density. Based on simply unit analysis, I figured that I could go in this direction: mol/L x g/mol x L/mL = g/mL
3. ## Chemistry AP-Density

The level of water in a graduated cylinder is at the 100 mL mark. When a platinum crucible floats on the surface of the water, the level reads 157.9 mL. When the crucible is totally immersed in the same cylinder, the level reads 102.70 mL. What is the
4. ## Chemistry

The calcium in a 150 mL sample of water from the Ogeechee River at a location near Savannah was determined by precipitating Ca2+ as CaC2O4.H2O (FW=146.115 g/mol). The precipitate was collected by filtration, washed and then ignited [turning the CaC2O4.H2O
5. ## Chemistry

For each of the following combinations of solutions, determine the mass of barium sulfate, BaSO4, that should precipitate...? For each of the following combinations of solutions, determine the mass of barium sulfate, BaSO4, that should precipitate. (Begin
6. ## chemistry

How will the relative number of moles of Mg and O be affected if the following procedural errors are made? Briefly explain (1) the crubile is not brought to constatn mass before the Mg is added. (2) water is not added after the first heating of Mg, and the
7. ## Chemistry

Use the data given to calculate the value of delta G rxn for the reaction at 25C 2C(graphite)+H2(g)--->C2H2(g) C H2 C2H2 S(J K^-1 mol^-1)| 5.74 |130.68| 201.0 ------------------- delta H(kJ/mol) | 0 | 0 |-226.8 a.-291.4 kj b.-244.3 Kj c.-226.8 kj
8. ## chemistry

I have two that I can not figure out: #1: calculate the MOLALITY of 10.00 g/L of the salt, if its molar mass is 100.0 g/mol and solution density D=1.100 g/mL work: 10.00 g NaCl x (1mL/1.100g) x (1kg/1000 mL)= 0.00909 kg 100.0 g x (1 mol NaCl/58.4 g Nacl)=
9. ## solving Equations

Solve x square pluse 5x subtracting by 6 equals zero? X^2 + 5x - 6 = 0 Solve by factoring. 3 and 2 will do it. heres the right answer.... (x-1)(x+6)=0 x=1 x=-6 Let's see if that is the right answer. The first number is the product of the first two numbers;
10. ## Chemistry

PLEASE fully explain these...I've already tried to figure them out and failed terribly... thanks so much 4. 5.6 x 10-6 mol of A and 5 x 10-5 mol of B are mixed in a 200 mL flask. The system is represented by the equation: At equilibrium, there is 4.8 x
11. ## chemistry

A flask has a mass of 78.23 g when empty and 593.63 g when filled with water. When the same flask is filled with concentrated sulfuric acid, H2SO4, its mass is 1026.57 g. What is the density of concentrated sulfuric acid? (Assume water has a density of
12. ## physics

A flask has a mass of 78.23 g when empty and 593.63 g when filled with water. When the same flask is filled with concentrated sulfuric acid, H2SO4, its mass is 1026.57 g. What is the density of concentrated sulfuric acid? (Assume water has a density of
13. ## Chemistry

Please help me figure out where I went wrong. HNO3 + KOH -> KNO3 + H2O enthalpy change = -53.4 kJ/mol 55.0 mL of 1.30 mol/L solutions of both reactants, at 21.4°C, are mixed in a calorimeter. What is the final temperature of the mixture? Assume the
14. ## chemistry

Can someone help me to check my answer and the way I solve this problem is right or wrong? Determine the energy required to turn a Na metal atom into a gas phase ion (Na+ (g)). Ionization energy of Na(g) 499 kJ/mol Electron affinity of O(g)for2e- 603
15. ## Chemistry

2KClO3 --> 2KCl + 3O2 What mass of O2 can be made from heating 125 g of KClO3? I know that the answer is 49 g O2 but I keep getting a completely different answer, can anyone show me what I'm doing wrong? 125g KClO3 x (2 mol KClO3/ 122.49g KClO3) = 2.04
16. ## Chemistry

Element X has a face-centered cubic unit cell structure. If the density of the element is measured to be 12.4 g/cm^3, what is the atomic radius of X? units are in pm (picometers) MM: 102.9055 g/mol I have done this 4 different times and came up with the
17. ## chemisrty

which element results if 2 protons and 2 neutrons are ejected from a radium nucleus with atomic num 88 and mass num 226 how do i go about this please can you help If you can add you can do these. 88Ra226 ==>2X4 + zzYww. Now make the numbers add. Protons
18. ## to dr bob..chemistry

bottle of wine contains 13.1% ethanol by volume. The density of ethanol (C2H5OH) is 0.789 g/cm3. Calculate the concentration of ethanol in wine in terms of mass percent and molality. mass percent _______% molality ______mol/kg Thanks Responses AP CHEMMMM -

Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS + 7O2 --> 2Fe2O3 + 4SO2 Calculate the % yield. My Answer: nFeS=23.4g/87.92 g/mol =0.266 mol 4mol FeS /
20. ## college chemistry

Mg and O lab how will the relative number of moles of mg and o be affected if the following procedural errors are made? a)crucible is not brought to constant mass before the Mg is added. b)water is not added after the first heating of Mg, and the entire
21. ## college chem

Mg and O lab how will the relative number of moles of mg and o be affected if the following procedural errors are made? a)crucible is not brought to constant mass before the Mg is added. b)water is not added after the first heating of Mg, and the entire
22. ## Chemistry

A student dried a wet crucible with a kimwipe. A piece of kimwipe was left clinging to the inside wall of the crucible. The student did not see the piece of kimwipe when adding the NaHCO3-KCl mixture to the crucible. The crucible and its contents were
23. ## Chemistry

A solution is made by dissolving 0.100 mol of NaCl in 5.35 mol of water. What is the mass % of NaCl? So far, I have determined molecular weight of NaCl (58.44 g/mol) multiplied by 0.100 mol = 5.844g NaCl, and mw of H2O (18 g/mol) = 96g H20. I thought mass
24. ## French for Aubrey

Leçon 4 = PRESENT TENSE OF REGULAR -IR VERBS BATIR = to build AFFIRMATIVE I build, I am building, I do build je bâtis tu bâtis il bâtit elle bâtit on bâtit nous bâtissons vous bâtissons ils bâtissent elles

26. ## Chemestry

How much heat (in kJ}) is required to vaporize it? (Assume a density of 1.00 g/mL ) I have this 60.0ML/ 1.00 g/ml = 60grams 60/153/81 g/mol = .3900916715 moles .3900916715 moles / 43.9 kj/mol = 17.122 And it keeps telling me the answer is wrong.
27. ## Chemstry Help Drbob!

How much heat (in kJ}) is required to vaporize it? (Assume a density of 1.00 g/mL ) I have this 60.0ML/ 1.00 g/ml = 60grams 60/153/81 g/mol = .3900916715 moles .3900916715 moles / 43.9 kj/mol = 17.122 And it keeps telling me the answer is wrong.
28. ## 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
29. ## Chemistry/lab math

I think I have these figured out correctly but I'm not sure if I might have converted in the wrong direction; The rate of the enzyme activity of a certain reaction is a. 0.0027 μmol/min/mL. Express it as __ μmol/min/L My answer: 2.7
30. ## Dr.Bob

A 100.0 mL sample of 0.05 M NH3 is titrated with 0.10 M HCl. Determine the pH of the solution after the addition of 50.0 mL HCl. Here is my work: NH3 + H3O+ --> NH4+ + H2O Before Addition: NH3= 0.005 mol H3O= 0 mol NH4+ = 0 mol Addition: NH3 = 0.005 mol
31. ## chemistry

A student dried a wet crucible with a Kimwipe. A piece of Kimwipe was left clinging to the inside wall of the crucible, The student did not see the piece of Kimwipe when adding the NaHCO3-KCl mixture to the crucible. The crucible ans its contents were
32. ## Math

What do you call numbers that cannot be arranged into 2-row arrays? multipication After some research I finally understand the question. Those would be the odd numbers or the numbers without a factor of 2 in them. After much stress and contemplating, I
33. ## College Chemistry

If 69.3g of magnesium chloride were produced from a process with a known yield of 78.3%, find the mass of carbon tetrachloride in grams that was used. Equation: 2CCl4 + MgCrO4 -> 2COCl2 + CrO2Cl2 + MgCl2 I was able to solve it but I just don't
34. ## Math

Too lazy to use the calculator, lol. 22 times (90) divided by 30 times 2,000 to the 4th power plus six. Answer please!
35. ## Chemistry

Perpare 500ml of 1M HCl solution from a bottle of concentrated 37%(W/W) HCL stock with a density of 1.19g/ml. 37%= 37/100 x 100 therefore mass is 37g molarity = mol/vol 1= mol/0.5 mol=0.5 mass of Hcl needed = molxmr mass = 0.5 x 36.5 mass = 18.25g
36. ## Chemistry

I'm having a problem with a simple conversion question! "What is the molarity of 30.0 g of NH3 in 70.0 g of water? The desnity of the solution is 0.982 g/mL, and the molecular weight of ammonia is 17.0 g/mol" 1.76 mol NH3 Vsolution = mass/density V=
37. ## Chemistry

A 0.100 mol sample of H2S is placed in a 10.0 L reaction vessel and heated to 1132°C. At equilibrium, 0.0285 mol H2 is present. What is the value of Kc at this temp? 2 H2S(g) 2 H2(g) + S2(g After I do my calculations, I get Kc= (0.0057)2 X
38. ## chemistry

My work: pH = -log(x) = 4.49 x = 3.2359e-5 3.2359e-5 = 5.72/M When I solved for M, I got that large number... 176764.8987 Ka for a given weak acid is 5.72 x 100. What concentration of acid (mM/L) will give a pH of 4.49? I got 176764.8987 M (not converted
39. ## Physics

Urgent. A density bottle weigh 0.25 when empty and 0. 75 when. Filled with water and 0.65N when filled with alcohol calculate the volume of water,the density of alcohol. Take density of water=1000kg/m3 acceleration due to gravity= 10m/s
40. ## Chemistry

Benzene has a vapor pressure of 100.0 Torr at 26°C. A nonvolatile, nonelectrolyte compound was added to 0.309 mol benzene at 26°C and the vapor pressure of the benzene in the solution decreased to 60.0 Torr. What amount (in moles) of solute molecules
41. ## Chemistry

A 100 mL container is filled with 0.01 mol of A2B3. At equilibrium, it also contains 0.006 mol of B. Find the value of K. A2B3(g) --> 2A(g) +3B(g)
42. ## calculus problem I have tried 100 times

A tank in the shape of an inverted right circular cone has height 5 meters and radius 4 meters. It is filled with 2 meters of hot chocolate. Find the work required to empty the tank by pumping the hot chocolate over the top of the tank. The density of hot
43. ## Chemistry

Can you check if this is correct please? a) How many moles of sodium hydroxide are there in 19.00 cm3 of 0.100 mol dm3? My answer: 0.0019 mol b) How many moles of hydrochloric acid are, there in 25.00 cm3 of the acid solution? My answer: 0.0019 mol c) How
44. ## Chemistry URGENT

I need help to evaluate if I completed my experiment calculation. determination of water in a hydrate. 1. Mass of crucible, and cover = 18451.3 2. Mass of crucible, cover and sample = 23410.2 3. Mass of crucible, cover and sample after 1st heating =
45. ## CHEM HELP

I asked this already but for some reason the answer I got isnt being accepted online Question: In the laboratory, 3.50 grams of salicylic acid were reacted with 7.20 ml of acetic anhydride (density equal to 1.08 g/ml). Determine the limiting reagent. I

Find the length of the 3rd side of each right triangle. 1. 8^2+15^2=c^2 Answer: c=17 2. 5^2+b^2=13^2 Answer: b=12 3. 9^2+13^2=c^2 Answer: c~15.81 Simplify. Assume that all variables are nonnegative. { this means square root 4. {12 Answer: 2{3 5. 2{75
47. ## Jr. High Pressure Challenge Question

A small flask has a mass of 22.71 g. When it is filled with water the total mass is 153.38 g. When it is filled with milk the total mass is 157.67 g. What is the density of milk?

The probability of winning a game is 25%. How many times should you expect to win if you play 36 times? A. 3 times B. 7 times C. 9 times (I think it's the answer) D. 11 times Please help me! If I'm wrong can someone please explain to me why and the correct
49. ## General Chemistry I

A sample of a compound containing only Br and O reacts with an excess of H2 to give 6.601 g of HBr and 3.919 g of H2O. What is the empirical formula of this compound? a. BrO b. BrO2 c. Br2O d. BrO3 e. None of the above I already know the answer is (e), but
50. ## AP Chem

2) For a theoretical yield of 19 g and actual yield of 11 g, calculate the percent yield for a chemical reaction. Answer in units of %. 11 g / 19 g times 100 = 57.89% in your 2 sigfig problem, you might be expected to round off to 58%
51. ## Chem

I'm having a lot of trouble with a simple problem. I have a 3.0% by man solution of H2O2 in H2O. The density of thr solution is 1.0 g/mL. I need to find the molarity. How do I do this? So far I have: 3.0g H2O2 x 1 mol/34.02 g= .0881 mol I'm not sure where
52. ## Math

A cylinder has a radius of 2 feet and a height of 18 feet. Volume (to the nearest tenth) = a0 cubic feet i TRIED to work out this problem. The answer I got was 226.3 I used the cylinder volume formula which is π r2 h.! The computer says my answer is
53. ## Chemistry

I cannot understand how the mass of the system has changed. There's no need for you to do my work please just explain it to me! :) thanks so much A scientist placed copper powder into a crucible and heated it until all of the copper reacted. The resulting
54. ## physics

A density bottle has a mass of 35g when empty,85g when filled with water and 75g when filled with kerosene.Calculate the density of kerosene in g/cm3
55. ## Physics i.e science

A density bottle has a mass of 35g when empty, 85g when filled with water and 75g when filled with kerosene. Calculate the density of kerosene in g/cm3.
56. ## Chemistry-Dr.Bob, I need you!!!!

You can mix 100.mL of 1.0 M HCl with 100 mL of 1.0 NaOH, both at 25 degree Celcius. The temperature of your calorimeter rises by 5.98 degree C, and its heat capacity is 100 J/degre C. How much energy is released per mol of H2O formed? My answer: 6x10^6 J
57. ## AP Chemistry

Calculate the moles of CO2 formed when 4.2 mol of C3H8 react with 20.6 mol O2. Answer in units of mol. So, the balanced equation is C3H8 + 5 O2 ==> 3 CO2 + 4 H2O . I thought the answer would be 12.36 mol, but when I type it in it's wrong. Please help!
58. ## AP Chem

Hey guys! Thanks for any help in advance! I'm back with this problem: Calculate the percent dissociation for a 1.00 × 10-6 M solution of HCN at 25 °C. Ka = 4.90 × 10-10. So my question really is do I have to use water when I calculate the percent
59. ## Physics

A 10cm times 10cm times 10cm wood block with a density of 700kg/m^{3} floats in water. What is the distance from the top of the block to the water if the water is fresh? weight= density*volume*g weight=700*(0.001)*9.81 weight=6.86newton
60. ## Chemistry

I need help I can't seem to get the right answer. Please help! 1/2 H_2 (g) + 1/2 Cl_2 (g) --> HCl (g) -92.3 kJ/mol Na(s) + 1/2 O_2(g) + 1/2H_2(g) --> NaOH(s) -426.8 kJ/mol NaCl(s) --> Na(s) + 1/2Cl_2(g) 411.1 kJ/mol H_2O(l) -->H_2(g) +
61. ## AP CHEM

Complete and balance the reaction Al(s) + Pb2+(aq) ! using the smallest possible integers. I got: 2Al(s) + 3Pb2 ==> Al2Pb3 Calculate the standard free energy. Faraday’s constant is 96485 J V · mol Answer in units of kJ/mol. I know the formula is -nFE
62. ## Acid-Base chem

Which of the following would for a buffer if added to 250.0 mL of .150 M SnF2? a).100 mol HCl b).060 mol HCl c).040 mol HCl d).040 mol NaOH e).040 mol HF I figured I could find out the pH of the solution with HCl/NaOH/HF added, and then find the pH when
63. ## chemistry

calculate the grams of 1.8% (m/m) NaCl solution that contains 8.00 g of NaCl I tried 1.8 times 8.00g divided by 58.44g times 100 my answer is 24.6g rounded to 2 SF is 25g this truned out to be wrong I'm stumped!
64. ## Chemistry - Periodic Table+IE(check+help)

The following data lists the ionization energies for a given atom: IE1 = 738Kj/mol; IE2 = 1451Kj/mol; IE3 = 7733Kj/mol. Predict the valence electron configuration for this atom, and explain your reasoning. i do not understand this question but i will give
65. ## Chemistry - Periodic Table+IE(check+help)

The following data lists the ionization energies for a given atom: IE1 = 738Kj/mol; IE2 = 1451Kj/mol; IE3 = 7733Kj/mol. Predict the valence electron configuration for this atom, and explain your reasoning. i do not understand this question but i will give
66. ## chemistry

A 50.0 mL sample of 0.50 M HBr is titrated with 0.25 M KOH. What is the pH after the addition of 60.0 mL of KOH? A) 4.1 B) 13.4 C) 1.7 D) 2.0 E) 7.7 I'm confused on the process of solving this problem. My work so far: .050L X .50 mol/1L= .025 mol HBR .060L

Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS = 7O2 --> 2Fe2O3 + 2SO2 Calculate the % yield. My Answer: nFeS=23.4g/87.92 g/mol =0.266 mol 4mol FeS /
68. ## gr. 12 chemistry

Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS = 7O2 --> 2Fe2O3 + 2SO2 Calculate the % yield. My Answer: nFeS=23.4g/87.92 g/mol =0.266 mol 4mol FeS /

Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS = 7O2 --> 2Fe2O3 + 2SO2 Calculate the % yield. My Answer: nFeS=23.4g/87.92 g/mol =0.266 mol 4mol FeS /
70. ## Enthalpy (chemistry 105)

23.0mL of water density of water is 1.00 g/mL 1g = 1ml 23g of water Cs of water 4.18 J/(gC) moles= 2.40g/72.0(g/mol)= .033 mass = 23g+2.4g = 25.4g Ti= 14.5 C Tf= 25.0 C Calculate the enthalpy change, ΔH, for this reaction per mole of X. I'm getting -33.4
71. ## Chemistry

A student cleaned a crucible with HCl. After pouring the HCl into the waste container, the crucible was neither rinsed with water or dried before the student added the NaHCO3 and KCl mixture. The crucible contained some residual HCl. How would this
72. ## chemistry

When I have the table filled out, what would I need to do in order to calculate the solubility product for calcium hydroxide? The following is what I have in mind, please tell if I am incorrect or correct. Ksp = [Ca+2][OH-1]2 You should have an average
73. ## Chemistry

Benzene has a vapor pressure of 100.0 Torr at 26°C. A nonvolatile, nonelectrolyte compound was added to 0.309 mol benzene at 26°C and the vapor pressure of the benzene in the solution decreased to 60.0 Torr. What amount (in moles) of solute molecules
74. ## Chemistry

So I have had several homework problem like this and managed to solve them easily, but these two problems I cannot get the correct answer for. Using a Table of thermodynamic data, calculate the change in Gibbs free energy for each of the following
75. ## Chemistry

Calculate the molarity of the following solutions: 5.0g of KOH in 4.0L of KOH solution I went from grams of KOH to moles of KOH to molarity but still got the wrong answer... 5.0g KOH X 1 mol KOH/56.108g KOH = 5.0 mol KOH/56.108=0.0891 mol KOH/4.0L and got
76. ## Chemistry

hmmm...I just can't seem to get it. It looks like I got it right up to the volume of the metal point. Don't I have to divide the mass of the metal by the density of the water given before? (0.9970)? I guess I am having a problem with this which results in

T1/2(Ra-226) = 1602 years What is the activity of 1 gram of Ra-226? Give the answer in Ci and Bq? What would be this activity after 1T1/2 and 5T1/2? Someone please help me with this question.
78. ## Chemistry

An empty crucible was heated to drive off any volatile impurities and weighed after cooling (see below). A small amount of the green complex iron salt was added to the crucible, weighed again, and then heated gently to remove any waters of hydration

T1/2(Ra-226) = 1602 years What is the activity of 1 gram of Ra-226? Give the answer in Ci and Bq? What would be this activity after 1T1/2 and 5T1/2? Would appreciate if someone could show me how to do this question. Thanks.
80. ## Intro to chem

What is the volume of 19.7g of oxygen at STP? Heres what i got but did not get the same answer..pls tell me where i am wrong! (grams to moles) 19.7g x 1 mol/ 16.00 = 1.23 mol Oxygen (Pv=nRT) looking for V 1.23 mol x 0.0821 x 273K / 1.00 atm = 27.57 CORRECT
81. ## Chemistry

For a particular reaction at 195.1 °C, ΔG = -1488.09 kJ/mol, and ΔS = 288.67 J/(mol·K).? Calculate ΔG for this reaction at -20.0 °C. delta G = delta H - (T*delta S) -1488.09 kJ/mol = (delta H) - ((461.8K)*(+288.67 J/(mol x K))*(1 kJ/1000
82. ## Chem

Determine the number of moles of N atoms in 43.5 g of Mg(NO3)2. Textbook answer: 1.43 mol N My answer: 43.5 g Mg(NO3)x x (1 mol Mg(NO3)2/148.313 g Mg(NO3)2) x (2 mol N/1 mol Mg(NO3)2) = .293 Can tell me where i went wrong?
83. ## Chemistry

Given 2.05 mol Hg find mass Hg 2.05 mol Hg x 200.59g Hg / 1 mol Hg =411g Hg My question is would my answer be wrong if I put it in scientific notation 4.11E2
84. ## physical science

A rectangular container measuring 16cm times 46cm times 67 cm is filled with water what is the mass of this volume of water in kilograms and grams? (take the density of water to be 1000 kg/m cube
85. ## Science- physics

A balloon weighing 80 kg has a capacity of 1200 m3. If it is filled with helium, how great a payload can it support? The density of helium is 0.18 kg/m3 and the density of air is 1.30 kg/m3. Express your answer in Newtons. I know the answer is 12, 400
86. ## chemistry

How much pure calcium carbonate (100.09 g/mol) is required to produce 40.0 mL carbon dioxide gas according to the reaction used in this experiment? Your unknown will contain between 25-100% calcium carbonate. Answer to 3 significant figures. Do not include
87. ## For DrBob

Methods and Materials: The starting materials for this lab were: a crucible, breakfast cereal (Kix), bun cent burner, 100 mL beaker, hot plate, 100 mL volumetric flask and stopper, a funnel and filter paper. First off by taking the breakfast cereal crushed
88. ## Chemistry

An aqueous antifreeze solution is 40.0% ethylene glycol (C2H6O2) by mass. The density of the solution is 1.05 g/cm3. Calculate the molality, molarity, and mole fraction of the ethylene glycol. molality I actually can do this whole problem EXCEPT for one
89. ## Chemistry II

1. Under water where the temperature is 17oC and the pressure is 394 kPa, a diver inhales 2.1 L of air from his SCUBA tank. a) How many moles of gas are in his lungs? b) If the diver swims to the surface without exhaling where the temperature is 32oC and
90. ## math help, correction

Anna has 12 bills in her wallet, some \$5 and some \$10. The total value of the bills is \$100. HOw many of each bill odes Anna have? How do i solve these type of problems my quess was this but i don't know if i'm correct. 5(x) + 10(y) = 100 5(0) + 10y = 100
91. ## math

what is the square root of 5z-2, then it says plus 7=10 First, subtract 7 from each side so you now have: sqrt(5z-2)=3. Then square each side, so you now have: 5z-2=9. Then add 2 to each side so you have 5z=11. Then divide each side by 5 and the answer is
92. ## Chemistry

An unknown hydrate of copper (II) oxalate is to be identified in the lab. The following data was collected by a student: Mass of crucible 23.776 g Mass of crucible + hydrate 24.889 g Mass of crucible + anhydrate 24.530 g Thank you
93. ## Chemistry

A critical reaction in the production of energy to do work or drive chemical reactions in biological systems is the hydrolysis of adenosine triphosphate, ATP, to adenosine diphosphate, ADP, as described by ATP(aq) +H2O (l) --->ADP(aq) +HPO4^2- for which
94. ## Literature;Crucible.

i have to pick one character from the Crucible who decides that they have chosen the wrong action and change their behavior, this switch is often motivated by a number of factors...i have to tell their original course of action and how they change, their
95. ## Ethnics

I truely need help i just don't understand anything and I've read so many times the chapters that I just can't comprehend anything nomore. I have a test on the first friday of november. I'm trying to answer all the questions in the study sheet and these
96. ## Science

The densities of the Jovian planets are A. not more than about 0.5 times the density of water. B. not more than about 1.5 times the density of water. C. from 3.9 to 5.5 times the density of water. D. more than 5.5 times the density of water. Reset
97. ## Composite Materials

Can someone please help with this problem? A burnout test was performed to determine the volume fractions of constituents in a glass/epoxy composite. The following observations were made: Weight of empty crucible = 47.6504 g Weight of the crucible and
98. ## chemistry

hi kinda stuck :) 100.0 ml of 0.100 M H2NNH2 (kb =3.0 x10^-6) is titrated by 0.200M calculate PH after adding the following volumes of HNO3 a 0 b 25.0 ml c 50.0 ml d 60.0 ml ----------------------------------------- A) N2H4 + HNO3 --> N2H5+ + NO3- .100
99. ## science

A relative density bottle has a mass of 40g when empty, 90g when filled with water and 80g when filled with oil. Calculate the relative density of the oil.
100. ## Ochem

What volume of eugenol will be present in 30 mL of distillate? The essential oil found in cloves, eugenol, can be isolated by steam distillation because it is insoluble in water and has a measurable vapor pressure at 100 °C even though it has a much