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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
How many kcal are needed to raise the temperature of 120 g of water from 15°C to 75°C?

Chemistry
For each of the following precipitation reactions calculate how many grams of the first reactant are necessary to completely react with 55.8 g of the second reactant. K2SO4 + Sr(NO3)2 + SrSO4 + 2KNO3

CHEMISTRY
The enthalpy of cimbustion for Octane vapor, C8H18, a component of gasoline, is -5512.0kJ/mol. a. Write the equation for the combustion of Octane, including the energy term. b. Calculate the energy change when 45g of Octane burn. c. Calculate the energy produced when 45g of ...

Chemistry
What intermolecular forces are responsible for neoprene's stretchiness?

Chemistry
How much energy, in calories, does it take to convert 20.0 grams of solid water, at 0.0 degrees C, into liquid water, at 0.0 degrees C? (The enthalpy of fusion for H2O is 1.44 kcal/mol)

Chemistry
How many grams of AlCl3 are produced when 53.0 g of Al reacts?

chemistry
Ethanol has an enthalpy of evaporation of 38.6kJ/mol, and a normal boiling point of 78.4oC. What is the vapor pressure of ethanol at 15oC? Hint: the normal boiling point is when the vapor pressure reaches 1 atm. Use, . Pay attention to use right units

chemistry
2. 50.0 mL of 1 M NaOH(aq) and 50.0 mL of 1 M HNO3(aq), both initially at 18.6°C, were mixed in a Styrofoam cup calorimeter. The temperature of the solution rose to 25.4°C. How much heat was released? Assume that the heat capacity and density of the solution are the same as ...

Chemistry
write a balanced nuclear equation for the reaction that occurs when uranium-335 absorbs a neutron and undergoes fission to produce 3 neutrons, bromine-65 and another nucleus.

chemistry
2. 50.0 mL of 1 M NaOH(aq) and 50.0 mL of 1 M HNO3(aq), both initially at 18.6°C, were mixed in a Styrofoam cup calorimeter. The temperature of the solution rose to 25.4°C. How much heat was released? Assume that the heat capacity and density of the solution are the same as ...

chemistry
Using the electron configuration of nickel (Ni), identify its magnetic character. a. ferromagnetic b. paramagnetic c. no magnetic character d. diamagnetic

Chemistry
How many moles of carbon are in a 28.0g sample? I have no idea where to start

Chemistry
A sample of plant extract is subjected to thin layer chromatography using aluminum backed plates of 0.25 mm thickness. The sample extract is suspected to contain a series of related compounds with hydroxyl and ester functional groups. Suggest a suitable solvent or solvent ...

Chemistry
True or False? An identical cylinder filled with the same pressure of hydrogen contains more molecules because hydrogen molecules are smaller than oxygen molecules.

Chemistry
A student is given 2.94g of a mixture containing anhydrous MgCl2 and KNO3. To determine the percentage by mass of MgCl2 in the mixture, the student uses excess AgNO3 to precipitate the chlorides ios as AgCl Starting with the 2.94g sample of the mixture dissolved in water, ...

Chemistry pls help DR.BOB
What intermolecular forces are responsible for neoprene's stretchiness?

Chemistry
Calculate the pH of a solution made by mixing 60.0 ml of 0.80 M N2H4 (a weak base) with 50.0 ml of 0.50 M HCl. (Kb for N2H4=1.7 x 10^-6) Can I use the Henderson Hasselbach equation here?

chemistry
The radius of a strontium atom is 215 pm. How many strontium atoms would have to be laid side by side to span a distance of 2.66 mm?

chemistry
A metal x form different chlorides.If 12.7g of chloride A and 16.3g of chloride B contains 7.1g and 10.7g of chlorine respectively show that the figures agree with the law of multiple proportions. write their formular

chemistry
What is the predicted change in the boiling point of water when 4.00 g of barium chloride (BaCl2) is dissolved in 2.00 kg of water? Kb of water = 0.51°C/mol molar mass BaCl2 = 208.23 g/mol i value of BaCl2 = 3 A. 0.0016°C B. -0.0049°C C. -1.0°C D. 0.015°C

chemistry
What is the predicted change in the boiling point of water when 4.00 g of barium chloride (BaCl2) is dissolved in 2.00 kg of water? Kb of water = 0.51ÃÆÃ​€™Ãƒâ€ ​...

chemistry
3HgO→2Hg+O2 Which of the following can definitely be concluded from the equation and heat of reaction above? A. The reaction is spontaneous. B. The reaction is non-spontaneous. C. The reaction is endothermic. D. The reaction is exothermic. E. None of these.

Chemistry
How do you obtain pure crystals of sodium chloride from a mixture of sodium chloride and activated carbon powder

chemistry
A sample of ethanol 0.78g was burnes at a final temperature of 20.9°c. The mass of water is 50.0g. Calculate the standard enthalpy change of combustion of ethanol.

Chemistry
Assume that you have a liquid in a cylinder equipped with a movable piston. There is no air in the cylinder, the volume of space above the liquid is 200 mL, and the equilibrium vapor pressure above the liquid is 29.0 mm Hg. What is the equilibrium pressure above the liquid ...

Chemistry
solid sodium reacts violently with water producing heat, hydrogen gas and sodium hydroxide. How many molecules of hydrogen gas are produced when 65.4g of sodium are added to water? 2Na(s)+ 2H2O(l) -->. 2NaOH(aq) + H2(g). Can someone please explain this question and it's ...

chemistry
4.8g of Mg were burn in 3.2g of oxygen. The MgO produced at a mass of 8g what is the equation of the reaction

General chemistry
Calculate the molarity of 500.0 ml solution containing 26.5g Na2CO3

General chemistry
How many grams of potassium sulfate are needed to prepare 150 ml of a 6.50 m/v% potassium sulfate solutions

General chemistry
What is the m/m% of NaOH in a solution prepared with 40.0 g NaOH and 400.0 g of water

chemistry
Instead of oxalate anion, if we use ethylenediamine as the bidentate ligand, what would be the product? What are the donor atoms in en?

CHEMISTRY
Write a balanced ionic equation for the redox reaction in dilute acidic solution between trioxodate(v)anion (IO3) AND IODIDE ANION (I)

chemistry
The radius of a niobium atom is 131 pm. How many niobium atoms would have to be laid side by side to span a distance of 3.20 mm?

Chemistry
Density is an important property of matter. The density of 25oC dry air at sea level is 1.29 g/L. What is the mass unit for dry air? What is the volume unit for dry air?

chemistry
a certain volume of a gas 298k is heated such that its volume and pressure are now four times their original values. what is the new temperature

Chemistry
In my upcoming lab we are extracting caffeine from tea through distillation. I was wondering why adding CaCO3 helps this process? Is it due to the basic nature of CaCO3 which decreases the polarity of the caffeine, making it less reactive with water?

Chemistry
An isotope, X, of a particular element has an atomic number of 15 and a mass number of 31. Which of the following statements are true? I. X is an isotope of phosphorus. II. X has 16 neutrons per atom. III. X has an atomic mass of 30.973

Chemistry
A piece of metal has a mass of 0.010107 kg. When it was placed into a 100-mL graduated cylinder containing 30.0 mL of water, the volume of water increased to 32.3 mL. What is the density of the metal (g/mL)?

Chemistry
Sarin is a nerve gas with a chemical formula of C4H10FO2P. What is the mass of one molecule of sarin?

Chemistry
Need help with my last question! Given the following reaction: 2NH3 (g) + 5F2 (g) ---> N2F4 (g) + 6HF (g) If 4.00 g of NH3 and 14.0 g of F2 are allowed to react, how many grams of HF can be produced?

Chemistry
A 0.446-gram sample of iron ore is dissolved in HCl and the iron (Fe solid) is reduced to Fe2+. The solution is then titrated by 38.6mL of 0.105 N KMn)4. Calculate the percentage of Fe in the iron ore sample.

Chemistry
A gas mixture consists of equal masses of methane (molecular weight 16.0) and argon (atomic weight 40.0). If the partial pressure of argon is 200. torr, what is the pressure of methane, in torr? I am coming out with 443torr, but the listed options are 80.0 torr b. 200. torr c...

Chemistry
A gas mixture consists of equal masses of methane (molecular weight 16.0) and argon (atomic weight 40.0). If the partial pressure of argon is 200. torr, what is the pressure of methane, in torr?

chemistry
The density of diamond is 3.51g/cm^3,and the density of platinum is 21.43g/cm^3.If equal masses of diamond and platinum are transferred to equal volumes of water in separate graduated cylinders,which graduated cylinder would have the greatest volume change? can you show me a ...

chemistry
if you burned 3.0 g of magnesium and produced 5.0 g of product how much oxygen gas was used ?

chemistry
The density of diamond is 3.51 g/cm^3 and the density of platinum is 21.43g/cm^3. If equal masses of diamond and platinum are transferred to equal volumes of water in separate graduated cylinders, which graduated cylinder would have the greatest volume change? Explain or show ...

CHEMISTRY!!
What intermolecular forces are responsible for neoprene's stretchiness?

AP Chemistry Help!!
When you light a candle, the paraffin wax soon begins to melt. Paraffin wax is a covalent compound. Can you classify the melting of the wax as a chemical change or a physical change? If so, which is it? If you cannot classify it as chemical or physical, explain why not. ...

Chemistry
If 26.4 grams of nitrogen and 30.1 grams of oxygen combine to form nitrogen monoxide, how many grams of nitrogen monoxide must form? I am confused on how to do the math.

Chemistry
Determine the mass of CaCO3 in your TUMS tablet? The weight of the tablet was 0.013g Concentration of HCl was 0.1494 M Volume of HCl was 95 mL Concentration of NaOH was 0.1422 M The average amount it took to titrate was 2.13 mL I have determined that moles of HCl neutralized ...

chemistry
what mass of copper is deposited from copper sulfate when a current of 0.22 A is passed through the solution for 15 minute

Organic Chemistry
I honestly can't figure out how to draw this structure and it's especially difficult for online homework. I've used up 2 tries and only have one more left! Can someone please help? Thank you so much! CH3C≡C(CH2)3C(CH3)3

Chemistry
1) What volume of oxygen gas at 28 Celsius and 102 kPa is needed to react completely with 150 g of iron according to the following reaction. Fe(s) + O2 (g) FeO(s) 2) A bunsen burner is lit in a lab that at 24.7 Celcius and 1.07 atm. What mass of water is produced in the ...

Chemistry
The balanced equation for the synthesis of water is: 2H2 + O2 > 2H2O If I have 5.5 grams of water, at least how many grams of Oxygen gas was needed?

Chemistry
Iron (III) Oxide reacts with Aluminum to form Aluminum Oxide and Iron. If I have 255 g of Aluminum and unlimited Iron (III) oxide, how many grams of Iron will form? I am really not sure how to work with this. What does it mean when it says that the iron is unlimited, how would...

chemistry
how do you convert 7.5% w/v NaCI to mM

Chemistry
Calculate deltaH for the reaction NO (g) + O (g) ----> NO2(g) given following NO + O3 ----> NO2 + O2 deltaH=-198.9 kj O3 ---> 3/2 O2 deltaH= -142 kj O2 -----> O2(g) deltaH=495

science chemistry
Explain how Particles moves in solid lead,molten solid,gaseous lead in these three state of matter

Chemistry
A sample of metal has a mass of 24.28g, and a volume of 5.53 mL. What is the density of this metal

Chemistry
Acetone is a common solvent and has a density of 0.7899 g/mL. What volume of acetone has a mass of 28.7g

Chemistry
Does Oleic acid have larger molecules than water molecules? and what type of bonding does oleic bonds have?

Chemistry
Assume that you have a liquid in a cylinder equipped with a movable piston. There is no air in the cylinder, the volume of space above the liquid is 200 mL, and the equilibrium vapor pressure above the liquid is 29.0 mm Hg. What is the equilibrium pressure above the liquid ...

Chemistry
How much energy (in kilojoules) is released when 29.0 g of ethanol vapor at 88.0 ∘C is cooled to -10.0 ∘C? Ethanol has mp = -114.5 ∘C, bp = 78.4 ∘C, ΔHvap = 38.56 kJ/mol and ΔHfusion = 4.60 kJ/mol. The molar heat capacity is 113 J/(K⋅mol) for the liquid and 65.7 J...

chemistry
With information on the inside cover of the book, calculate how many mL of 70.4 wt% nitric acid should be diluted to 0.250 L to make 3.00 M HNO3. (Answer:47.5 mL)

Chemistry
The volume of a sample of a gas is 41.5 L at 8.28 atm and 467 K. What volume in L will it occupy at 3.03 atm at the same temperature?

chemistry
72g of Mg reacted with 32g of oxygen to form 48g of Mg. So %yield of Mgo

Chemistry
Hardness is defined as calcium and magnesium ion content. Since most hardness is caused by carbonate mineral deposits and does not distinguish calcium and magnesium ions, hardness is usually reported as parts per million (ppm) of calcium carbonate (CaCO3, by weight). A water ...

Chemistry
In this reaction: 2 HCl + Na2CO3 -> H2O + CO2 + 2 NaCl The HCl was diluted from 2M to 0.8M and I currently have 0.020 L of it. There is also Na2CO3. What would be four causes for a large error percentage? Is it possible that some of the HCl evaporated?

Chemistry
How much ice (in grams) be added to lower the temperature of 355 mL of water from 25 ∘C to 5 ∘C ? (Assume the following: the density of water is 1.0 g/mL, the ice is at 0 ∘C, the heat of fusion of ice is 6.02 kJ/mol, and the volume of water produced by the melting ice is...

Chemistry
Determine the mass of chlorine produced when 200A of current flows for 24 hours through a cell of molten NaCl.

Chemistry
Calculate the minimum time, in minutes, required to deposit 40g of copper using a current of 20A.

Chemistry
Write the symbol for the elements that fit the following descriptions 1. 10 electrons in each -3 ion 2. 18 electrons in each +2 ion 3. The alkaline earth metal in the third period

chemistry
H3PO4 + 3KOH = K3PO4 + 3 H2O What would be the percent yield if you reacted 49.0g of H3PO4 with 112g of potassium hydroxide, and collected 25.0g of water?

Chemistry
Radon-222 is a radioactive gas with a half-life of 4 days. Approximately how much of a 40 g sample of radon-222 would remain after 12 days?

Chemistry
If 23.2 grams of ammonium nitrite react to form 10.1 grams of nitrogen, how many grams of water must simultaneously be formed?

Chemistry
For the reaction of 2 HCl + Na2CO3 -> H2O + CO2 + 2 NaCl, how can I visually identify the limiting reagent, without any calculations? If I have a very high percent yield, what would be a good reason for it, considering that the HCl was diluted to 0.050 L at 0.8 M ...

Chemistry
"What volume of water must be added to 100ml of 15 M of H2SO4 to dilute to 5.0M?" I've tried using lots of different methods but keep having the same answer and don't know if the answer book is wrong or if it's me. Thanks!

chemistry
how many unpaired electrons are in this configuration 1s2 2s2 2p6 3s2 3p3

chemistry
how many unpeeled electrons are in this configuration 1s2 2s2 2p6 3s2 3p3

Chemistry help??!
A student reduces the temperature from a 300 cm3 balloon from 60°C to 20°C. What will the new volume of the balloon be? 264 cm3 <my answer choice 100 cm3 300 cm3 341 cm3

chemistry
which characteristics of solid, a liquid, and a gas are exhibited by each of the following substances? how would you classify each substance? A. a bowl of pudding will be solid and B. a bucketful of sand wiil be solid

chemistry
when water boils, there is bubbles that rise to the surface of the water. What is inside these bubbles? air

Chemistry
What is the oxidation state of Fe in Fe(CO)5

chemistry
The molecular formula of 2.68g hydrated sodium sulphate is Na2SO4.nH2O.If the mass loss on heating is 1.26g then calculate the value of n.

Chemistry
why homemade ice cream normally weighs twice the amount of commercially made ice cream

chemistry
The following unbalanced equation describes the reaction that can occur when lead (II) sulfide reacts with oxygen gas to produce lead (II) oxide and sulfur dioxide gas: PbS + O2  PbO + SO2. all i need help on is explaination of the electron transfers that would happen in ...

Chemistry
Assume that 5.00 grams of zinc react with excess HCl according to the following equation: Zn + 2HCl = ZnCl2 + H2 The hydrogen was collected over water at 20.0C and the prssure of the atmosphere is 751 mmHg. The pressure of the water vapor at 20C is 17.5 mmHg. How many moles of...

math sets
out of 320 students at a university,190 taking math,235 taking chemistry and 120 taking physics.125 are taking both chemistry and math,95 taking both chemistry AND PHYSIC,55 TAKING BOTH MATH AND PHYSICS.HOW MANY ARE TAKING ALL THE THREE SUBJECTS

Chemistry
How many moles of H are there in 8.9 moles of C4H8O2?

Chemistry
How many moles of Cl ions are there in 8.5 moles of CaCl2 ?

Chemistry
How to make 100 mL of 100mM of Tris HCl and 100 mL of 100mM of Tris Base. Follow the pH of the resulting combined solution as it is heated from 4 to 50 degrees Celsius. I did not use the HH equation in this problem. I started with just converting to moles needed and then to ...

Chemistry
How to Prepare 500mL a 50 mM pH 6 Citrate buffer starting from citric acid as the sole source of conjugate base I used the HH equation and got that citric acid concentration would be 0.035M, when converted to moles would be 3.362g. Then I was planning to add that amount to a ...

Chemistry
How is it possible that the atomic number increases in order, yet the atomic masses do not? A. There is no relationship between the atomic number and mass of the atom. B. The masses of the protons for Te, I, and Xe have slightly different masses. C. Since the numbers of ...

Chemistry
Which of the following best explains how relative atomic mass could be determined from the type of data available to Dalton? A. By determining the mass of oxygen contained in a sample of water, its exact atomic mass could be determined. B. By comparing the masses of hydrogen ...

Chemistry
2.40 L of N2, at 25 ∘C and 1.89 atm , is mixed with 2.60 L of O2, at 25 ∘C and 0.245 atm , and the mixture allowed to react. N2(g)+O2(g)→2NO(g) How much NO, in grams, is produced?

Chemistry
If we were to fill a bottle with boiling hot water than place it in a bucket filled with cold water what would happen to the bottle and why? i know the bottle would get crushed inwards but whats the science behind this can someone explain?

Chemistry
I'm doing a lab where I have to identify the oxidization state of Iron. Here's the procedure I had to go through: Use 0.5 molar concentration of CuSO4, get another beaker and add 0.1 grams of Iron to it. Add the CuSO4 to the beaker with the Iron fillings. Wait for the reaction...

chemistry
Your living room measures 45 ft by 62 ft. The cost of the carpet is $21/square yard. How much will you spend on carpet

chemistry
We have 1L of 0.1mol/l solution of ammonium chloride, with pKa 9.2 for NH4+/NH3 Place in an increasing order on a pKa axis the different conjugate acid /base pairs present in the solution. Write the equation of the different reactions that may take place

Chemistry
Calculate enthalpy of the reaction ethene+hydrogen gives ethane are -1410KJ,-286kJ and -1560KJ respectively at 25°c

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