Saturday
December 7, 2013

# Posts by marcus

Total # Posts: 208

Chemistry
When 1.150 grams of an unknown nonelectrolyte dissolves in 10.0 grams of water, the solution freezes at -2.16°C. What is the molecular weight of the unknown compound? Kf for water = 1.86°C/m. -2.16 x m/-1.86 = 1.16 1.16/ .010 kg of water= 116 1.150/116= 9.91 g/mol is t...

Chemistry
A solution contains 10.0 g pentane, C5H12, 10.0 g hexane, C6H14 and 10.0 g benzene, C6H6. What is the mole fraction of hexane? I figured the equation would be: ___ M Hexane x 10 Divided by 30 =Mole fraction of Hexane?

Chemistry
What mass of water must be used to dissolve 20.0 grams of ethanol, C2H5OH, to prepare a 0.0500 molal solution of ethanol?

Chemistry
What is the molality of an aqueous solution that is 10.0% ethanol, C2H5OH, by mass?

Chemistry
The rate of a reaction A ---> B is expressed by the rate expression rate=k(A)2. If the molar concentration of A is tripled, the rate of the reaction should increase by a factor of some many?

math
how do I write equation for the following? input a 20/28/36/44/52 output b 5/7/9/11/ ? ? is 13

Math
You have 2/3 bag of flour. Use 3/4 of the flour to make cookie dough. How much of the entire bag do you use to make cookie dough?

Math
The teacher asked Laura to give each student 2/5 sheets of paper. If there are 20 students in the class how much paper did Laura pass out?

GRAMMAR
WRITE AN ARTICAL ABOUT CALIFORNIA GOLD RUSH

chemistry
My chem book gives me the following Hess' Law example: Mg + 2HCl --> H2 MgCl2 Delta H1 MgO +2HCl --> H2O +MgCl2 Delta H2 H2 + 1/2 O2 --> H2O Delta H3=-68.3kcal The desired reaction is the formation reaction of MgO as follows: MgS +1/2 O2 --> MgO Delta H final= ...

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