Tuesday
May 3, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
sample of alumium has a mass 6.3g.calculate the number of mole of alumium present and the number of atom of alumium in the sample(AL=27
Saturday, January 16, 2016 by Hassan

Chemistry
Which of the following compounds contains both ionic and covalent bonds? SiO2 LiCN LiI PCl3
Friday, January 15, 2016 by Jordan

Chemistry
Aqueous hydrobromic acid will react with solid sodium hydroxide to produce aqueous sodium bromide and liquid water. Suppose 61. g of hydrobromic acid is mixed with 41.1 g of sodium hydroxide. Calculate the maximum mass of water that could be produced by the chemical reaction
Friday, January 15, 2016 by Ryan

Chemistry 101
A rectangular prism has these dimensions and mass: Length = 12.6cm, width = 1.256 feet, and thickness = 456 mm. Its mass is 1.2347 pounds. Determine its density in g/cm3.
Friday, January 15, 2016 by mike

Chemistry
hellop
Friday, January 15, 2016 by mike

chemistry
which of the following has highest binding energy (nuclear chemistry) Fe-56 , O-16 , H-3 , U-235 and explain why
Friday, January 15, 2016 by ahmed

Chemistry
When 46.0 ml of 0.18 M HNO3 and 58.0 ml of 0.23 M LiOH are mixed, the concentration of [OH-] after mixing is ?
Friday, January 15, 2016 by Has

Chemistry
When its brakes are applied, a car moving at 10 m/s undergoes an acceleration of -1.2 m/s2. How far does the car travel before it comes to a stop?
Friday, January 15, 2016 by Autumn

Chemistry
In a closed container 1L of chlorine reacts with 1L of nitrogen and 1L of hydrogen. I need to give lewis structure, vsepr, box notation for valence electrons etc. (i know how to do this) But I'm doubting on what the reaction equation would be.
Friday, January 15, 2016 by Nicolas

chemistry
why iron 56 has highest binding energy than oxygen 16 , although oxygen 16 more stable than iron 56 ???
Friday, January 15, 2016 by ahmed

chemistry
the half-life of tritium is 12.26 y what would be the rate of decay of tritium atoms per second in 1.00 L of hydrogen gas at STP containing 0.15% tritium atoms ?
Friday, January 15, 2016 by ahmed

Chemistry
Would a substance that has a granular appearance, is not soluble, melts under a bunsen flame, and does conduct as a solid or liquid have an ionic, covalent or metallic bond?
Friday, January 15, 2016 by Anonymous

Chemistry
Would a substance that is shiny, does not dissolve in water, does not melt under a bunsen flame, and does not conduct as a solid have a covalent, ionic, or metallic bond?
Friday, January 15, 2016 by Anonymous

chemistry
1 gm of magnesium is burnt in a closed container which contains 2 l of air at ntp containing 21 percent oxygen by volume find limiting reagent, mass of excess reagent left over, mass of mgo produced, number of mg and oh ion formed by dissolving it with water
Thursday, January 14, 2016 by David

Chemistry
A compound contains 69.9% iron and 30.1% oxygen. What is its empirical formula?
Thursday, January 14, 2016 by Anonymous

Chemistry
Why are the atomic masses of elements usually decimal numbers?
Thursday, January 14, 2016 by Mads

Chemistry
A student calculates the empirical formula of a compound to be C1.5H3.5. Express this as a correct empirical formula.
Thursday, January 14, 2016 by Anonymous

Chemistry
A 15.00 g chunk of lustrous silver metal is heated to 50.0 degrees C and is then placed in a coffee cup calorimeter containing 50.0 mL of water at 15.30 degrees C. After equilibrium, the water temperature is measured to be 16.56 degree C. Suggest which metal or metals could ...
Thursday, January 14, 2016 by Lana

Chemistry
Write a balanced chemical equation and determine the enthalpy of combustion for carbon in the diamond allotropic form. Is this the correct chemuc eq? C + O2 ----> CO2?
Thursday, January 14, 2016 by Lana

Chemistry
Combustion of natural gas (primarily methane) occurs in most household heaters. The heat given off in this reaction is used to raise the temperature of the air in the house. Assuming that all the energy given off in the reaction goes to heating up only the air in the house, ...
Thursday, January 14, 2016 by Lana

chemistry
A sample of nitrogen has a volume of 50.0L at a pressure of 760mmHg. What is the volume of the gas at each of the following pressures if there is no change in temperature? A. 1500mmHg B. 4.00 atm C. 0.500atm
Thursday, January 14, 2016 by brian

Chemistry
CH4 + O2 = CO2 + H2O AND the change in heat is minus 890. Now the question is what is the energy bond of (C=O)?
Thursday, January 14, 2016 by Akhter

chemistry
the half-life of tritium is 12.26 y what would be the rate of decay of tritium atoms per second in 1.00 L of hydrogen gas at STP containing 0.15% tritium atoms ?
Thursday, January 14, 2016 by ahmed

chemistry
the half-life of tritium is 12.26 y what would be the rate of decay of tritium atoms per second in 1.00 L of hydrogen gas at STP containing 0.15% tritium atoms ?
Thursday, January 14, 2016 by kiloa

chemistry
calculate the ph of a buffer solution containning 0.1M acetic acid and a 0.1M solution of sodium acetate
Thursday, January 14, 2016 by dagi

chemistry
the half-life of tritium is 12.26 y what would be the decay of tritium atoms per second in 1.00 L of hydrogen gas at STP containing 0.15% tritium atoms ?
Thursday, January 14, 2016 by kiloa

chemistry
in todays experiment what length of magnesium ribbon would be required to generate 42.00 ml's of H2?
Thursday, January 14, 2016 by Mahnoor

chemistry
What would be the mass ratio of Pb-208/Th-232 in a meteorite that is approximately 4.5 × 10^9 years old? The half-life of Th-232 is 1.39 x 10^10 years i'm used t= 3.32 t(1/2) logNo/N but the result is not correct !?
Thursday, January 14, 2016 by ahmed

Chemistry
Would a substance that is shiny, does not dissolve in water, does not melt under a bunsen flame, and does not conduct as a solid have a covalent, ionic, or metallic bond?
Wednesday, January 13, 2016 by Anonymous

Chemistry
The concentration of barium ions in any solution can also be determined via gravimetric analysis. An impure sample of barium nitrate with a mass of 1.234 g, is completely dissolved in water and the resulting solution is reacted with an excess of aqueous sodium sulfate. A ...
Wednesday, January 13, 2016 by sarah

Chemistry
How many grams of iron can be recovered from 11.8 kg Fe3O4? I tried to multiply 11.8 kg by the percent composition of iron, but that didn't work.
Wednesday, January 13, 2016 by Anonymous

CHEMISTRY
1.) 2 methylpropene is a compound used to make synthetic rubber. A sample of 2 methylpropene contains 0.566 g C and 0.0933 g H. Determine its empirical formula
Wednesday, January 13, 2016 by JESSICA

Chemistry
In a few concise sentences, explain how you could predict the products of a chemical reaction using the reaction between sodium nitrate and magnesium phosphate as an example?
Wednesday, January 13, 2016 by Anonymous

Chemistry- Dr.Bob!
Combustion of natural gas (primarily methane) occurs in most household heaters. The heat given off in this reaction is used to raise the temperature of the air in the house. Assuming that all the energy given off in the reaction goes to heating up only the air in the house, ...
Wednesday, January 13, 2016 by Lana

Chemistry
In a few concise sentences, explain how you could predict the products of a chemical reaction using the reaction between sodium nitrate and magnesium phosphate as an example?
Wednesday, January 13, 2016 by Anonymous

Chemistry
The concentration of barium ions in any solution can also be determined via gravimetric analysis. An impure sample of barium nitrate with a mass of 1.234 g, is completely dissolved in water and the resulting solution is reacted with an excess of aqueous sodium sulfate. A ...
Wednesday, January 13, 2016 by sarah

Chemistry
Combustion of natural gas (primarily methane) occurs in most household heaters. The heat given off in this reaction is used to raise the temperature of the air in the house. Assuming that all the energy given off in the reaction goes to heating up only the air in the house, ...
Wednesday, January 13, 2016 by Lana

chemistry
both beta and positron emission are observed for artifically produced radioisotopes of low atomic number bot only beta emission is observed with naturally occuring radioisotopes of high atomic number what is the reason ?
Wednesday, January 13, 2016 by hani

chemistry
isotope A require 12h for its decay rate to fall to 1/64 of its intial value . isotope B has half-life = 1.5 half life of A how long does it take for decay rate of B fall to 1/32 of its initial value ?
Wednesday, January 13, 2016 by ahmed

chemistry
A current of 5A was passed through a solution of nickel (1)(1))salt.find the time taken for 6g of nickel to be deposited
Wednesday, January 13, 2016 by dele Japhet

Chemistry Chemical Reactions pls help <3
2AgNO3 + CaCl2 ---> Ca(NO3)2 + 2AgCl all of the substances involved in this reaction are soluble in water except AgCl which forms a solid at the bottom of the flask . Suppose we mix together a solution containing 12.6 g of AgNO3 and one containing 8.4 g of CaCl2 .What mass ...
Wednesday, January 13, 2016 by Claire

Chemistry
We allow 24.0 g of CH4 to react as completely as possible with excess O2, to form CO2 and H2O . Write the balanced equation for this question . What mass of O2 reacts?
Wednesday, January 13, 2016 by Egemen

Chemistry
Ionic bond sometime known as mutualism bond justify the validity of this statement
Wednesday, January 13, 2016 by Malugu ikinah

Chemistry
A 50.0g sample of copper at 10.0 C is placed in 200.0g H20 at 40.0 C in a calorimeter. Heat flows from the water to the copper until both are at 39.3 C. What is the specific heat of copper? (Csp H20 is 4.18J/g*C.) I don't have any idea how to do this problem. If someone ...
Wednesday, January 13, 2016 by Karen

Chemistry
Are the bonds for these substances correct? Sodium chloride - ionic Sucrose - covalent Copper - metallic Calcium chloride - ionic Carbon - covalent Mercury - ionic Naphthalene - covalent Are any of these substances not strictly ionic, covalent, or metallic?
Wednesday, January 13, 2016 by Anonymous

chemistry
what are the step by step methods that are required in adding Na2CO3 to a tank of water ?
Wednesday, January 13, 2016 by bash

Chemistry
How many molecular does 36.0 grams of water represent?
Wednesday, January 13, 2016 by Anithe

chemistry
What mass of carbon dioxide can be produced from 4 moles of sodium bicarbonate according to the following unbalanced reaction, NaHCO3 --> Na2CO3 + CO2 + H2O?
Tuesday, January 12, 2016 by johnny

chemistry
an ezyme -catalysed reaction was carried out in a solution buffered with 0.05 M phosphate ph 7.2 . As a result of the reaction ,0.06M of acid was formed. (phosphoric acid has three pka values. The one required for this calculation is pka2=7.2). 1) what was the pH at the end of...
Tuesday, January 12, 2016 by josh

Chemistry
An ion of sulfur has a smaller atomic radius than a neutral atom of sulfur because it loses an electron when becoming an ion. True or False?
Tuesday, January 12, 2016 by Jessica

chemistry
can someone explain to me what happens when zinc and copper sulfate react? I know its a redox reaction and it gives off heat making it exothermic, but don't know whats actually happening in that reaction. can someone explain to me that reaction?
Tuesday, January 12, 2016 by will

Chemistry
What mass of sulfur must be used to produce 12.6L of sulfur dioxide (SO2) at STP? S8 + O2  SO2
Tuesday, January 12, 2016 by Donovan

Reposting chemistry help!!!
A metal x forms two different chloride.if 12.g of chloride A and 16.3g of chloride B contain 7.1g and 10.7g of chlorine respectively,show that the figure agree with the laws of multiple proportions.write there formulea plz i need the working.....
Tuesday, January 12, 2016 by Daniel

chemistry
how many liters (at STP) of chlorine gas are required to produce .050L of hydrogen chloride gas?
Tuesday, January 12, 2016 by k

Chemistry
What does potassium nitrate form when it decomposes
Tuesday, January 12, 2016 by Nicole

Chemistry chlorine plz help
A metal x forms two different chloride.if 12.g of chloride A and 16.3g of chloride B contain 7.1g and 10.7g of chlorine respectively,show that the figure agree with the laws of multiple proportions.write there formulea plz i need the work....no hint plz
Tuesday, January 12, 2016 by Daniel

chemistry
Calcium carbonate was reacted with hydrogen chloride. What is the percentage yield of carbon(iv)oxide produced if 3.65g of the gas is collected when 10g of calcium(iii)oxocarbonate reacts
Tuesday, January 12, 2016 by tracia

Chemistry
pepe is tasked with carefully measuring precisely one mole of aluminum. How should pepe go about completing this assignment?
Monday, January 11, 2016 by Ivan

chemistry
What is the percentage by mass of sodium (Na) in a formula unit of sodium hydrogen carbonate (NaHCO3)?
Monday, January 11, 2016 by juan

chemistry
If I wanted to make two solutions. In one I will mix Chemical A into 1 Liter of water. In the second I will mix Chemical B into 1 Liter of water. If I want my two solutions to be the same concentration they should contain the same number of PARTICLES. How can I make sure both ...
Monday, January 11, 2016 by anthony

Chemistry
Part 1 : a.) How many grams of Hydrogen will be contained in a 100.000 g sample of magnesium hydroxide.? c.) How many grams of nitrogen will be contained in a 120.0 g sample of calcium cyanide? ________________________________________​ Part 3: d.) How many grams of ...
Monday, January 11, 2016 by Amber Deana B.

Chemistry
I'm confused on how to do these. Please show and explain how to do these. Test/quiz may be tomorrow. Pop Quiz!!! How do you calculate the percent composition of each of the following compounds? a.) Magnesium hydroxide b.) Calcium Cyanide c.) Nickel (ii) Iodide d.0 Copper (...
Monday, January 11, 2016 by Amanda

Chemistry
Why does magnesium burn with a white flame? What does it say about the electron transitions that take place?
Monday, January 11, 2016 by Anonymous

math/ chemistry
so I have this chemistry problem which involves math and basically I need to convert 62 g/mol into mol/L but I don't know how. like do you DIVIDE the g/mol by 1000 to convert g to L? and then how to you get the mol to become the numerator?
Monday, January 11, 2016 by kayla

Chemistry
One atmosphere of pressure will push a column of mercury to a height of 760 mm when the closs sectional area of the column is 1.00 cm.what would be the height of the column of mercury supported by the atmosphere if its cross sectional area were 0.500cm? How High would the ...
Monday, January 11, 2016 by gases laws and kinetic theory

Chemistry-Dr.Bob
You are at your cabin in the woods. Will you be able to take a hot bath tonight if only 0.1 lb of propane remains in the tank? Explain. My answer: No, I will not be able to take a hot bath. By making assumptions and approximations, I got... energy released for combustion is ...
Monday, January 11, 2016 by Sanaya

Chemistry-Dr.Bob
Why is gasoline (octane) better than diesal (cetane)?
Monday, January 11, 2016 by Sanaya

chemistry
A 20.00 g sample of metal is warmed to 165˚C in an oil bath. The sample is then transferred to a coffee cup calorimeter that contains 125.0 g of water at 5.0˚C. The final temperature of the water is 8.8˚C. mrtal water m=20g m=125g t1=165c t1=5 c=? t2=8.8 c...
Monday, January 11, 2016 by mariam

Chemistry
What is the chemical symbol for dihydrogen monoxide? I heard from the classmates and they laughed at each other. I can't understand!!
Monday, January 11, 2016 by Water-melon

chemistry
A flask containing 200 mL of solution is labeled 0.300 M CuBr2. A sample containing 0.0500 moles of Br− is added to the solution. What is the molarity of the Br− ion solution? Assume no volume change. a) 0.850 M b) 0.667 M c) 1.10 M d) 1.00 M e) 0.400 M
Monday, January 11, 2016 by bilawal

Chemistry
In what part of the electromagnetic spectrum would transition lines of n = 7 be expected to be found?
Monday, January 11, 2016 by Anonymous

Chemistry
Can a flame test and emission spectrum test be used to identify a mixture with two or three elements?
Sunday, January 10, 2016 by Anonymous

Chemistry
Why can't a single spectral line be used to identify an element?
Sunday, January 10, 2016 by Anonymous

Chemistry-Dr.Bob
Since most chemical reactions are conducted in containers open to the armisphere, why is the energy transfer associated with a chemical reaction generally expressed as the change in enthalpy? Is it because the enthalpy of reaction measures the change in energy of a chemical ...
Sunday, January 10, 2016 by Sanaya

chemistry
A lighter contains 3.59 g of butane. How many moles of butane are present at STP? Thoughts: So, correct me if I'm wrong however is it appropriate just to calculate its molar mass, and then use that molar mass and the given mass to figure out moles??
Sunday, January 10, 2016 by Gerry

Chemistry
In the lab, 5.8 L of methane gas is burned with excess oxygen gas at SATP. How much carbon dioxide gas is produced? **Based on the balanced chemical equation the ratio of methane gas to carbon dioxide is 1:1, this being said, does it make sense that as 5.8 L of methane gas is ...
Sunday, January 10, 2016 by Bob

chemistry
How many formula units are in 1.31 mg of hydrogen peroxide (H2O2)? Answer in units of formula units. For 508 g of butadiene (C4H6) calculate the number of moles. Answer in units of mol. Calculate the number of molecules. Answer in units of molec. 016 1.0
Sunday, January 10, 2016 by Erika

chemistry
How many molecules are in 24.0 g NO2? Answer in units of molec.
Sunday, January 10, 2016 by Erika

chemistry
How many molecules are in 0.0700 mol NH3? Answer in units of molec.
Sunday, January 10, 2016 by Erika

chemistry
How many molecules are contained in 1.30 mol O2? Answer in units of molec.
Sunday, January 10, 2016 by Erika

chemistry
How many grams do 6.2×1024 atoms of argon weigh? Answer in units of g.
Sunday, January 10, 2016 by Erika

Chemistry
Is this equation for acetic acid + sodium chloride balanced? C2H4O2 + NaCl ---> HCl + C2H3NaO2
Sunday, January 10, 2016 by Anonymous

chemistry
calculate the concentration of potassium in grams per liter after mixing 100ml of 0.250m and 200ml of 1.00m k2s04
Sunday, January 10, 2016 by Divao

chemistry
Mno4- + So3-2 = Mno2 + sO4-2 (in neutral solution,but H+ ions will appear in the final question) solve this redox reaction and give me the method also Thank you
Sunday, January 10, 2016 by taylor

Chemistry
Salts of barium, barium sulfate Particularly, When applied orally and because of its low solubility (Ksp = 1 x 10 ^ -10) Increase contrast for X-rays in medical diagnosis of the digestive system. Considering que Were reacted 7 × 10 -5 moles of CaCl2 with an equivalent ...
Saturday, January 9, 2016 by Igor

Chemistry
Salts of barium, barium sulfate Particularly, When applied orally and because of its low solubility (Ksp = 1 x 10 ^ -10) Increase contrast for X-rays in medical diagnosis of the digestive system. Considering que Were reacted ^ 7 × 10 -5 mol of CaCl2 with an equivalent ...
Saturday, January 9, 2016 by Igor

Chemistry
How much of a 50.0 grams sample of Uranium-238 would remain after 26 minutes IF the half-live is 13.0 minutes?? This question has stummed me and I can't do it, ugh.
Saturday, January 9, 2016 by Isbale

Chemistry-Dr.Bob
An unknown piece of metal weighing 100. g is heated to 90.0 degrees Celcius. It is dropped into 250 g of water at 20.0 degrees Celcius. When equilibrium is reached, the temperature of both the water and piece of metal is 29.0 degrees Celcius. Determine the specific heat of the...
Saturday, January 9, 2016 by Sanaya

chemistry
Is bp of para and meta and ortho isomer are same
Saturday, January 9, 2016 by debobrata

Chemistry
calculate the initial concentration of HCOONa you would add to 0.10M HCOOH to make a buffer with a pH of 4.00 [Ka (HCOOH) = 1.8 x 10^-4]
Saturday, January 9, 2016 by Christabel

chemistry
explain why metal oxides tend to be basic if the oxidation number of the metal is low and acidic if the oxidation number of the metal is high
Saturday, January 9, 2016 by Faye

Chemistry
100 mL 0.1 M sodium acetate solution is mixed with 50 mL 0.1 M acetic acid. If now 0.937 mL of 1 M sodium hydroxide is added to the buffer what is the change in pH? pKa (acetic acid) = 4.76
Saturday, January 9, 2016 by Jamie

Chemistry
reacting 3 mol C4H10 and 12 mol O2 will occur as a complete combustion, true or false
Saturday, January 9, 2016 by RN

Chemistry
The standard free energy of formation of nitric oxide, NO, at 1000. K (roughly the temperature in an automobile engine during ignition) is 77.5 kJ/mol. Calculate the equilibrium constant for the reaction
Saturday, January 9, 2016 by Anonymous

chemistry
55 gm laughng gas contains ---------gm N.
Saturday, January 9, 2016 by G.raju

chemistry
If 6.00g of carbon is heated in air, the mass of the product obtained could either be 22.0g or 14.6g depending on the amount of air present. Using calculations with what law will this be in accordance?
Saturday, January 9, 2016 by Divine phyavuh

Chemistry
20.0 mL of ethanol initially at 7.2 degrees Celsius is mixed with 31.7 mL of water initially at 28.9 degrees Celsius in an insulated beaker. Assuming no heat is lost, what is the final temp? I did not include the density, but I solved for mass, and have the SHC, for both. Don...
Friday, January 8, 2016 by Jennifer

chemistry
what is the total number of atoms in the compound (NH4)3PO4?
Friday, January 8, 2016 by Cayden

Chemistry
Will 100g of copper completely replace all the silver in 200g of silver nitrate
Friday, January 8, 2016 by T

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 per mol H2O I think we...
Friday, January 8, 2016 by Sanaya

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