Tuesday
February 21, 2017

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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 ...
Tuesday, January 24, 2017 by punch

chemistry
Using the electron configuration of nickel (Ni), identify its magnetic character. a. ferromagnetic b. paramagnetic c. no magnetic character d. diamagnetic
Tuesday, January 24, 2017 by cool

Chemistry
How many moles of carbon are in a 28.0g sample? I have no idea where to start
Tuesday, January 24, 2017 by Tyler

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 ...
Monday, January 23, 2017 by Shariah

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.
Monday, January 23, 2017 by Vivian

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, ...
Monday, January 23, 2017 by Shariah

Chemistry pls help DR.BOB
What intermolecular forces are responsible for neoprene's stretchiness?
Monday, January 23, 2017 by AP Chem!

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?
Monday, January 23, 2017 by Hayley

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?
Monday, January 23, 2017 by Anonymous

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
Monday, January 23, 2017 by Emmanuel

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
Monday, January 23, 2017 by lu

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€ ​...
Monday, January 23, 2017 by Anonymous

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.
Monday, January 23, 2017 by KO

Chemistry
How do you obtain pure crystals of sodium chloride from a mixture of sodium chloride and activated carbon powder
Monday, January 23, 2017 by Aces

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.
Monday, January 23, 2017 by feussom

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 ...
Monday, January 23, 2017 by Impossible

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 ...
Monday, January 23, 2017 by Kim

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
Monday, January 23, 2017 by makwin

General chemistry
Calculate the molarity of 500.0 ml solution containing 26.5g Na2CO3
Monday, January 23, 2017 by Chin

General chemistry
How many grams of potassium sulfate are needed to prepare 150 ml of a 6.50 m/v% potassium sulfate solutions
Monday, January 23, 2017 by Chin

General chemistry
What is the m/m% of NaOH in a solution prepared with 40.0 g NaOH and 400.0 g of water
Monday, January 23, 2017 by Chin

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?
Monday, January 23, 2017 by yibralign tageese

CHEMISTRY
Write a balanced ionic equation for the redox reaction in dilute acidic solution between trioxodate(v)anion (IO3) AND IODIDE ANION (I)
Monday, January 23, 2017 by DAVIES

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?
Monday, January 23, 2017 by lisah

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?
Sunday, January 22, 2017 by Kaitlan

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
Sunday, January 22, 2017 by sikemi

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?
Sunday, January 22, 2017 by Andy

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
Sunday, January 22, 2017 by dillon

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)?
Sunday, January 22, 2017 by tammi

Chemistry
Sarin is a nerve gas with a chemical formula of C4H10FO2P. What is the mass of one molecule of sarin?
Sunday, January 22, 2017 by Madi

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?
Sunday, January 22, 2017 by kaitie

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.
Sunday, January 22, 2017 by Kayla

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...
Sunday, January 22, 2017 by Andrew

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?
Sunday, January 22, 2017 by Andrew

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 ...
Sunday, January 22, 2017 by summer

chemistry
if you burned 3.0 g of magnesium and produced 5.0 g of product how much oxygen gas was used ?
Sunday, January 22, 2017 by madison

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 ...
Sunday, January 22, 2017 by summer

CHEMISTRY!!
What intermolecular forces are responsible for neoprene's stretchiness?
Sunday, January 22, 2017 by Ben

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. ...
Sunday, January 22, 2017 by Heather

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.
Sunday, January 22, 2017 by Anonymous

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 ...
Sunday, January 22, 2017 by Miya

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
Saturday, January 21, 2017 by Jssica

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
Saturday, January 21, 2017 by SK

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 ...
Saturday, January 21, 2017 by Peter

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?
Saturday, January 21, 2017 by Erin

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...
Saturday, January 21, 2017 by Erin

chemistry
how do you convert 7.5% w/v NaCI to mM
Saturday, January 21, 2017 by homework

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
Saturday, January 21, 2017 by John

science chemistry
Explain how Particles moves in solid lead,molten solid,gaseous lead in these three state of matter
Saturday, January 21, 2017 by salman

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
Friday, January 20, 2017 by Jackie

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
Friday, January 20, 2017 by Jackie

Chemistry
Does Oleic acid have larger molecules than water molecules? and what type of bonding does oleic bonds have?
Friday, January 20, 2017 by Sci Guy

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 ...
Friday, January 20, 2017 by Sci Guy

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...
Friday, January 20, 2017 by Sci Guy

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)
Friday, January 20, 2017 by mojji

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?
Thursday, January 19, 2017 by dubz

chemistry
72g of Mg reacted with 32g of oxygen to form 48g of Mg. So %yield of Mgo
Thursday, January 19, 2017 by mohini

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 ...
Thursday, January 19, 2017 by KO

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?
Thursday, January 19, 2017 by Benjamin

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...
Thursday, January 19, 2017 by Anonymous

Chemistry
Determine the mass of chlorine produced when 200A of current flows for 24 hours through a cell of molten NaCl.
Wednesday, January 18, 2017 by kat

Chemistry
Calculate the minimum time, in minutes, required to deposit 40g of copper using a current of 20A.
Wednesday, January 18, 2017 by kat

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
Wednesday, January 18, 2017 by Marissa

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?
Wednesday, January 18, 2017 by andi

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?
Wednesday, January 18, 2017 by Luna

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?
Wednesday, January 18, 2017 by Anonymous

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 ...
Wednesday, January 18, 2017 by Benjamin

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!
Wednesday, January 18, 2017 by Josie

chemistry
how many unpaired electrons are in this configuration 1s2 2s2 2p6 3s2 3p3
Wednesday, January 18, 2017 by Emmanuel

chemistry
how many unpeeled electrons are in this configuration 1s2 2s2 2p6 3s2 3p3
Wednesday, January 18, 2017 by Emmanuel

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
Wednesday, January 18, 2017 by Vee

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
Wednesday, January 18, 2017 by eunice

chemistry
when water boils, there is bubbles that rise to the surface of the water. What is inside these bubbles? air
Wednesday, January 18, 2017 by eunice

Chemistry
What is the oxidation state of Fe in Fe(CO)5
Wednesday, January 18, 2017 by Anonymous

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.
Wednesday, January 18, 2017 by Farha

Chemistry
why homemade ice cream normally weighs twice the amount of commercially made ice cream
Tuesday, January 17, 2017 by Denya

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 ...
Tuesday, January 17, 2017 by amtonio

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...
Monday, January 16, 2017 by Michael

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
Monday, January 16, 2017 by kelvin

Chemistry
How many moles of H are there in 8.9 moles of C4H8O2?
Monday, January 16, 2017 by Ricardo

Chemistry
How many moles of Cl ions are there in 8.5 moles of CaCl2 ?
Monday, January 16, 2017 by Ricardo

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 ...
Sunday, January 15, 2017 by Aarya Singh

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 ...
Sunday, January 15, 2017 by Aarya Singh

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 ...
Sunday, January 15, 2017 by cool

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 ...
Sunday, January 15, 2017 by cool

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?
Sunday, January 15, 2017 by Julio

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?
Sunday, January 15, 2017 by Chem

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...
Sunday, January 15, 2017 by Alex Li

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
Sunday, January 15, 2017 by sharicka

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
Sunday, January 15, 2017 by angy

Chemistry
Calculate enthalpy of the reaction ethene+hydrogen gives ethane are -1410KJ,-286kJ and -1560KJ respectively at 25°c
Sunday, January 15, 2017 by Anonymous

Chemistry
In a certain reaction 0.20g of hydrogen gas combines with 3.20g of oxygen gas.if the relative molecular mass of the compound is 34.0 find its molecular formula (H=1,O=16).
Sunday, January 15, 2017 by feyonce

Chemistry - Enthalpy
When a 37.00 g silver spoon, initially at room temperature, is placed into 250.0mL of 90.00oC tea, it reaches a temperature of 85.00°C. The spoon will have gained ? J of thermal energy. I got 5237.5 Joules as (mass)x(specific heat capacity)x(Temperature change)=Heat, which ...
Saturday, January 14, 2017 by PleaseHelp

Chemistry
What will burning of .3 liters of C2H2 produce?
Saturday, January 14, 2017 by Ron

chemistry
Calculate pH of 6ml of 3M HNO3 diluted to 18 litres of water
Saturday, January 14, 2017 by Frederick

chemistry
1) Copy and complete: Two particles can react together only if they …… and the …… has enough …… to be ……. 2) What is meant by: a a successful collision? b an unsuccessful collision? 3) Reaction between magnesium and acid speeds up when: a)the concentration of ...
Saturday, January 14, 2017 by fiyin

Chemistry
If you had a basketball that was filled with mercury, about how much would it weigh? (The density of mercury is 13.6 grams per cubic centimeter.) First Hint: If you do not know the dimensions of a basketball, you should ESTIMATE them.
Saturday, January 14, 2017 by dsk

Chemistry
A large balloon contains 65.0 L of helium gas at 25 °C and a pressure of 745 mm Hg. The balloon ascends to 3000 m, at which the external pressure has decreased by 30.%. What would be the volume of the balloon, assuming it expands so that the internal and external pressures ...
Friday, January 13, 2017 by Sav

chemistry
Calculate the energies of the states of hydrogen atom with n=2 and n=3
Friday, January 13, 2017 by donald

Chemistry
Label the following changes as CHEMICAL or PHYSICAL change 1. Fat reacting with sodium hydroxide 2. Chemical A originally is buoyant in water; after it mixed with HCI, the new substance now sinks in water Label the following reactions as exothermic or endothermic 1. Ammonium ...
Friday, January 13, 2017 by Megan

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Homework Help: Science