Chemistry Question...Help Wanted?
When solid aluminium chloride is heated above 451 K, a vapour is formed which has Mr = 267. When this vapour is heated above 1100 K, the vapour has a Mr of 133.5. What are the molecular formulae of these two forms of aluminium chloride: At 460 K_______________ At 1150 K ________________ Show your work if you please. Thank you very much in advance.
Chemistry Questions Help?
Hello! I have a few questions on my Chem review that I can't figure out! Please help! In the laboratory, students wanted to mimic the inflation of an airbag by mixing sodium bicarbonate and acetic acid in a ziplock bag. Assuming you could conduct this experiment to fill up a four liter ziplock bag, determine the mass of the baking soda and the acetic acid needed to fill the bag. The reaction is below: NaHCO3 + CH3COOH ā H2O + CO2 + NaC2H3O2 The other one is: The Delta H value for a reaction is negative. Explain the difference in energy between products and reactants for this reaction. For the combustion of methane, write and balance the reaction and determine the enthalpy for standard heats of formation. Which would have a higher energy, products or reactants? Under what conditions does Hess's Law have to be used to determine enthalpy of an overall reaction.
Help wanted with chemistry question please?
A central atom is surrounded by four bromine atoms and an unknown number of lone pair (non-bonded) electrons. Which of the follow- ing combinations is possible for the electronic arrangement and molecular shape? 1. tetrahedral / angular 2. trigonal bipyrimidal / pyramidal 3. trigonal bipyrimidal / trigonal bipyrami- dal 4. trigonal bipyrimidal / seesaw 5. octahedral / square pyramidal 6. tetrahedral / pyramidal 7. trigonal bipyramidal /T-shaped 8. octahedral / octahedral
Chemistry questions, help wanted!?
Determine the grams of an organic compound (MW= 158 g/mol) which must be dissolved in 220 g of chloroform to lower the freezing point of the resulting solution to -66.1 C. A. 11.6 g B. 0.0143 g c. 69.8 g D. 2147 g When 0.579 g of an unknown compound are dissolved in 200 mL of a solution, the osmotic pressure was observed to be 39 torr at 25 C. what is the molecular weight of the compound? A. 116 g/mol b. 1380 g/mol C. 184 g/mol d. 165 g/mol pleaseee help && thank you!! (:
Chemistry goodies! Help wanted.?
What is the concentration (in M) of an ammonia solution if 12.12 grams of ammonia are dissolved in enough water to make 560.0 mL of solution? If a chemist has a stock solution of HBr that is 10.0 M and would like to make 450.0 mL of 3.0 M HBr, how would he do it? A chemist reacts 30.0 mL of 5.6 M HCl with an excess of Mg(OH)2 (supposed to be a small two) How many grams of magnesium chloride will be produced?
Excuse me help wanted for chemistry homework questions if explained will be 5 star.?
c) If 0.0586 L of hydrogen gas is collected in 5.00 minutes, calculate the rate of the reaction in mL of hydrogen gas per second. d) Using the reaction rate you calculated above, calculate the volume of hydrogen as produced in 23.0 minutes. e) Using the reaction rate you calculated above, calculate how long in minutes it takes to produce 1.50 L H2. f) 4. Use the reaction below to answer the following questions. 2 Ag(s) + Zn(NO3)2(aq) ! Zn(s) + 2 AgNO3(aq) f(A)) It is found that the rate of production of Zn(s) is 10.7 g/s. Calculate the mass of silver (in kg) reacted in 15.2 minutes. f(B)) If 14.3g of silver is used up in 5.0 minutes, what mass of zinc (in g) is formed in 45 seconds?
Chemistry question? Please help?
If you wanted to determine how much KOH (potassium hydroxide; a strong base) was dissolved in water, you could titrate it with a known amount of KHP (potassium hydrogen phthalate; a weak acid) until a color change indicates that the base is completely neutralized. The molecular equation below depicts this neutralization reaction. KHP(aq)+KOH(aq)āK2P(aq)+H2O(l) Write the net ionic equation that depicts the neutralization of the base by potassium hydrogen phthalate. Instead of using the entire chemical formula of phthalate, use HPā to represent the acidic hydrogen phthalate ion and P2ā to represent the phthalate ion. Please do not tell me to use a calculator or figure it out myself. I have been trying to answer this for hours and need to know so I can study my test.
Urgent help needed with this chemistry question, please, I'm desperate!?
How much of each starting material would you use to prepare 2.00 L of each of the following solutions? 0.250 M NaOH from 1.00 M NaOH stock solution and 0.290 M K2CrO4 from 1.75 M K2CrO4 stock solution (answers in L) Both answers would be great, but not needed. I just need the process explained so I know how to do it. Thanks\!
Help wanted with Chemistry Homework?
Hi, I need help with my chemistry homework.. I just need help how to do the problem Here is the question: A 0.25 g sample of pretzel is burned. The heat it gives off is used to heat 50. g of water from 18 Celsius to 42 Celsius. What is the caloric value of the pretzel in kcal/g?
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The specific heat tells you how much energy you need to raise the temperature of 1 gram one degree. (degrees in K are the same as in C for this purpose). You have 180g of water and you want to raise the temperature by 30 degrees so multiply these all together.. 180 x 30 x 4.18 = 22572J or 22.572kJ There you go....