Recent content by littlebearrrr

Oh, got it! Thanks for pointing that out; I fixed it above. I have a bad habit of equating the wrong things when reporting answers sometimes, even when the answer is right. I definitely need to work on that.

Ah, so it was just supposed to be 1.58s? Also, thanks for checking my answer. Appreciate it!

Homework Statement A ball of mass 125g is attached to a string .900 meters long. It is then set into vertical circular motion with 38 RPM. What is the tension of the string at the top of the circle and at the bottom of the circle? Homework Equations ∑Fy = may = marad arad = v2/R =...

Hi there! Wow, thank you for the very detailed explanation of your approach. I did not think to use vector notation to solve this problem. I'm going to try to solve this your way as soon as I get home from school! By the way, I'm wondering if your numbers were actually 5.57 ft/s and 21 degrees...

Homework Statement A rower's maximum speed in still water is 6.0 ft/s. He decides to cross a 60 ft. wide river (at his maximum speed), with an apparent heading of 30° north of east. The river's current (relative to the ground) is flowing south at a speed of 1.0 ft/s. Find the rower's speed and...

@ DrClaude and Chestermiller: Sorry for the late response. Thank you for reviewing my post. To DrClaude: I forgot to account for the temperature in my calculations, as noted by Chestermiller. I calculated the std. change in enthalpy and entropy, and used the values to find ΔG^o at 670K. Then I...

Homework Statement Estimate the value of the equilibrium constant at 670K for the following reaction: 2NO2(g)⇌N2O4(g)Homework Equations ΔG°rxn = -RT*lnKThe Attempt at a Solution This should be an easy problem. But for some reason, MasteringChem won't accept it, so I'm wondering if I did...

@ arildno: That's all right! I appreciate all of your help and patience so far; your wonderfully detailed posts helped me see this type of integral from a different perspective, and I learned the usefulness of changing the limits. I attempted to evaluate it again, and I got (1/4)(1-cos8). (or...

Hi, thank you for responding! Okay, I changed the limits of integration for y. After integrating for y and simplifying the new integrand, I got sqrt(4-z) * sin2z / 4-z = sin2z/sqrt(4-z). But since x=sqrt(4-z), then sin2z/sqrt(4-z) = sin2z/x (is that a correct statement to make?). From there, I...

Homework Statement Evaluate the triple integral of sin2z/(4-z) dydzdx where the limits of integration for outer limits (x) are from 0 to 2, the middle limits (z) are 0 to 4-(x^2), and the inner limits (y) are 0 to x.Homework Equations The Attempt at a Solution I'm not sure what the best...

Hey DrClaude, thanks for your help/checking my answers again :)

Homework Statement (NOTE: I solved the first two parts of this problem, but I included it anyway so you have background knowledge for the third question) The average kinetic energy of an electron in a ground-state helium atom is 2.4x10^3 kJ/mol. A. What is the corresponding electron...

Homework Statement I performed an experiment recently, which required me to heat a flask and an unknown compound to constant weight. The unknown was supposed to be a mixture of calcium sulfate dihydrate and NaCl. My goal for this lab was to determine the % NaCl in the mixture. My percent error...

Ahh, okay thanks! I solved it by swapping the middle and just multiplying the bottom by 4. I figured out what stumped me; it was not knowing how to get the unwanted compounds in the reactions to cancel out. I get it now though.

Homework Statement Calculate ΔH°rxn in kJ/mol for: C3H8(g) + 4 CO2(g) + 4 H2(g) → C7H16(g) + 4 O2(g) from the following given values of ΔH°rxn: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) ΔH°rxn= -2,010 kJ/mol C7H16(g) + 11 O2(g) → 7 CO2(g) + 8 H2O(g) ΔH°rxn= -4,426 kJ/mol H2(g)...