# Posts by Yuli

Total # Posts: 20

**physics**

how do you find time when all you're given are two different speeds the height and the angle?

*December 12, 2011*

**physics**

A toy rocket is traveling to the right at 15.0 m/s when it undergoes a constant acceleration 3.00 m/s^2 to the left how long does it take before the rocket stops moving to the right? what distance does the rocket travel before it stops moving to the right? what distance does ...

*December 11, 2011*

**chemistry**

A gaseous mixture in a 25.00 L container is made of 16.0 g N2 and 14.0 g Ar and has a total pressure of 1.00 atm. 1.Calculate the partial pressure of the N2 in the mixture. the ans is 0.620 atm 2.Calculate the temperature of the gas mixture. can someone explain to me how to do...

*December 8, 2011*

**chemistry**

cold water mass of calimeter+ water: 68.66g mass of calimeter: 19.19g mass of water: 49.47g final temperature of water: 39.1C initial temperature of water: 25.5C delta(T) of water: 13.6C hot water mass of calimeter+ water: 79.55g mass of calimeter: 20.61g mass of water: 58.94g...

*November 30, 2011*

**physics**

A 62.7-kg person jumps from rest off a 2.98-m-high tower straight down into the water. Neglect air resistance. She comes to rest 1.09 m under the surface of the water. Determine the magnitude of the average force that the water exerts on the diver. This force is ...

*November 28, 2011*

**physics**

A 65.0-kg skier coasts up a snow-covered hill that makes an angle of 27.4° with the horizontal. The initial speed of the skier is 6.37 m/s. After coasting 2.07 m up the slope, the skier has a speed of 4.06 m/s. Calculate the work done by the kinetic frictional force that ...

*November 28, 2011*

**physics**

A cable lifts a 1220-kg elevator at a constant velocity for a distance of 39.7 m. What is the work done by the tension in the cable? can someone help me with this the answer is supposed to be in joules i tried doing it by 1220(9.81)(39.7) = 475137J but that is not the answer ...

*November 27, 2011*

**chemistry**

A total of 2.00mol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 185g of solution. The reaction caused the temperature of the solution to rise from 21.0 to 24.7C . What is the enthalpy of this reaction? Assume that no heat is lost ...

*November 25, 2011*

**chemistry**

A piston has an external pressure of 9.00 atm. How much work has been done if the cylinder goes from a volume of 0.130 liters to 0.500 liters? can someone explain to me how am i supposed to do this please? Thanks :D

*November 25, 2011*

**chemistry**

In the following experiment, a coffee-cup calorimeter containing 100mL of H2 is used. The initial temperature of the calorimeter is 23.0 C . If 3.40g CaCl2 of is added to the calorimeter, what will be the final temperature of the solution in the calorimeter? The heat of ...

*November 24, 2011*

**chemistry**

how do i change 2866.0 J to kJ/mol? can someone please help me?

*November 24, 2011*

**chemistry**

I did all my questions but there is this last one i don't get. Calculate the number of moles of zinc that must have reacted( assume that Zn is limiting and the yield of H2 gas is 100%) how do you do this? could you help me with this last one please?

*November 24, 2011*

**chemistry**

how would you calculate the temperature of H2 in kelvin? and the moles that H2 produced? do you know a formula for that? could you please explain it to me thanks for all your help so far i've understood everything thanks to you.

*November 24, 2011*

**chemistry**

A student generates H2(g) over water using the reaction between zinc and hydrochloric acid Zn(s)+ 2HCl(aq)---> ZnCl2(aq)+ H2(g) Data: Mass of vial and zinc 15.5082 mass of vial 15.3972 mass of zinc 0.111 final burette reading 45.30mL barometric pressure: Patm 100.6kPa ...

*November 24, 2011*

**chemistry**

A student generates H2(g) over water using the reaction between zinc and hydrochloric acid Zn(s)+ 2HCl(aq)---> ZnCl2(aq)+ H2(g) Data: Mass of vial and zinc 15.5082 mass of vial 15.3972 mass of zinc 0.111 final burette reading 45.30mL barometric pressure: Patm 100.6kPa ...

*November 23, 2011*

**chemistry**

i know and i found a formula to do so. But i was wondering if you could tell me the formula to find the pressure exerted by H2 gas in kPa and also the one to find the kelvin temperature.

*November 23, 2011*

**chemistry**

A student generates H2(g) over water using the reaction between zinc and hydrochloric acid Zn(s)+ 2HCl(aq)---> ZnCl2(aq)+ H2(g) Data: Mass of vial and zinc 15.5082 mass of vial 15.3972 mass of zinc 0.111 final burette reading 45.30mL barometric pressure: Patm 100.6kPa ...

*November 23, 2011*

**chemistry**

A student generates H2(g) over water using the reaction between zinc and hydrochloric acid Zn(s)+ 2HCl(aq)---> ZnCl2(aq)+ H2(g) Data: Mass of vial and zinc 15.5082 mass of vial 15.3972 mass of zinc 0.111 final burette reading 45.30mL barometric pressure: Patm 100.6kPa ...

*November 23, 2011*

**mathematics**

given tanθ= -2√10/3 and π/2<θ< π find: a.sin2θ b.tan θ/2 could some1 help me with these 2 they're the only ones i couldn't get

*November 21, 2011*

**mathematics**

given sinθ=-5/13 and π<θ<3π/2 find sin2θ cos( θ-4π/3) sin(θ/2) can some1 please help me with this?

*November 21, 2011*

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