Most popular questions and responses by maath
  1. chemistry

    A chemist in a galaxy far, far away performed the Millikan oil drop experiment and got the following results for the charges on various drops. 2.52 ✕ 10-12 zirkombs 9.45 ✕ 10-12 zirkombs 3.78 ✕ 10-12 zirkombs 6.30 ✕ 10-13 zirkombs Use these data to

    asked on September 13, 2018
  2. math

    The volume enclosed by a sphere of radius r is (4/3)πr^3. The surface area of the same sphere is 4πr^2. You may already have noticed that the volume is exactly (1/3)r times the surface area. Explain why this relationship should be expected. One way is to

    asked on July 24, 2018
  3. Chemistry

    A 5.00 g sample of aluminum pellets (specific heat capacity = 0.89 J/°C·g) and a 10.00 g sample of iron pellets (specific heat capacity = 0.45 J/°C·g) are heated to 100.0°C. The mixture of hot iron and aluminum is then dropped into 94.9 g of water at

    asked on January 13, 2019
  4. chemistry

    Terephthalic acid is an important chemical used in the manufacture of polyesters and plasticizers. It contains only C, H, and O. Combustion of 21.79 mg terephthalic acid produces 46.18 mg CO2 and 7.10 mg H2O. If 0.250 mol of terephthalic acid has a mass of

    asked on October 8, 2018
  5. chemistry

    The enthalpy of fusion of ice is 6.020 kJ/mol. The heat capacity of liquid water is 75.4 J/mol degrees Celsius. What is the smallest number of ice cubes at 0 degrees Celsius, each containing one mole of water, necessary to cool 500. g of liquid water

    asked on January 28, 2019
  6. chemistry

    Why do some compounds and elements exist as a liquid at room temperature, while others are solids and gases? What forces are involved?

    asked on March 17, 2019
  7. chemistry

    Consider a mixture of air and gasoline vapor in a cylinder with a piston. The original volume is 40. cm^3. If the combustion of this mixture releases 950. J of energy, to what volume will the gas expand against a constant pressure of 650. torr if all the

    asked on December 23, 2018
  8. chemistry

    A 152g sample of ice at -37 degrees Celsius is heated until it turns into liquid water at 0 degrees Celsius. Find the change in heat content of the system. I'm really confused on how to solve this question knowing the fact that the state of the system is

    asked on January 14, 2019
  9. math

    If three dice are tossed, their sum could be 7. What is the probability of this? I'm guessing it's something to do with combinations?? I wrote down all the combinations of it equaling 7: 3, 3, 1 // 4, 2, 1 // 1, 5, 1 So I thought that since there are five

    asked on May 4, 2019
  10. math - probability

    What is the probability that this year's graduation will fall on the birthday of exactly one of the 336 Seniors? What is the probability that there is more than one such Senior?

    asked on April 10, 2019
  11. math

    The height of an object moving up and down is described by y=72+40cos18t (in degree mode). To at least three decimal places, confirm that the average speed of the object is 2/pi times its greatest speed.

    asked on November 26, 2018
  12. math

    Find the focus and directrix for the parabola y=ax^2. What special meaning does the expression 1/(4a) have?

    asked on November 11, 2018
  13. math

    There are many examples of graphs that have period 60 and whose y-values vary between -8 and 8. First, find a formula for such a function f, given that f(0)=8. Next, find a formula for such a function g, given that g(0)=0. For your f, also find the three

    asked on November 7, 2018
  14. english

    What is the deeper meaning of the poem, "A Lover" by Amy Lowell? This is her poem: "If I could catch the green lantern of the firefly I could see to write you a letter."

    asked on December 3, 2018
  15. chemistry

    why do molecules and ions with the same number of atoms and valence electrons have the same or similar molecular shape?

    asked on March 1, 2019
  16. math

    How do you find the value of m in the equation y=k+asin(mx)?

    asked on August 8, 2018
  17. Chemistry

    Thallium(I) hydroxide is a strong base used in the synthesis of some organic compounds. Calculate the pH of a solution containing 2.57 g TlOH per liter. I got 1.44 but I'm pretty sure that's wrong?

    asked on November 3, 2018
  18. chemistry

    Give the maximum number of electrons in an atom that can have these quantum numbers. 1. n = 3, ℓ = 2, mℓ = -1, ms = 1/2 2. n = 2, ℓ = 1, mℓ = -1, ms = -1/2

    asked on February 9, 2019
  19. chemistry

    Calculate the average kinetic energy of the N2 molecules in a sample of N2 gas at 266 K and at 532 K. I got 32.7 and 65.5 but they're wrong??

    asked on December 11, 2018
  20. math

    Let F1 = (0,2), F2 = (0,-2), and P = (x,y). Use the distance formula to convert the equation PF1 + PF2 = 6 into Cartesian form. Simplify your answer until it reaches the form hx^2+ky^2=m. I tried solving this but I got stuck with all the square roots and

    asked on August 9, 2018
  21. math

    what is the absolute value of infinity? is it just zero?

    asked on September 10, 2019
  22. math

    The focal points of a hyperbola are (0,6) and (0,-6), and the point (5,6) is on one of its branches. Find coordinates for the points where the hyperbola intersects its major axis. Also find equations for the asymptotes, and use them to help you draw the

    asked on February 22, 2019
  23. math

    Find p(p^-1(x)) when p(x)=x^2-4 I tried solving this and I got x^4-x+20 but that has no solution so I'm a little confused.

    asked on September 15, 2018
  24. chemistry

    Several compounds containing only sulfur (S) and fluorine (F) are known. Three of them have the following compositions. i. 1.188 g of F for every 1.000 g of S ii. 2.375 g of F for every 1.000 g of S iii. 3.563 g of F for every 1.000 g of S How do these

    asked on September 13, 2018
  25. chemistry

    You have a chemical sealed in a glass container filled with air. The glass container has a mass of 200.0 grams and the chemical has a mass of 650 grams. The total mass of the set-up is 850 grams. The chemical is ignited by means of a magnifying glass

    asked on September 12, 2018
  26. history

    What is a quasi-martial law? I looked this up on google but there's no direct answer to it.

    asked on October 13, 2018
  27. math

    Let F=(0,0) be the focus and the line y=-6 be the directrix. Plot several points P that are half as far from the focus as they are from the directrix. The configuration of all such points is an ellipse. Identify the four points where the ellipse crosses

    asked on October 18, 2018
  28. math

    Show that any dilation transforms any figure into a similar figure.

    asked on August 17, 2017
  29. chemistry

    What is the largest number of ions in any of your formulas? What is the total positive charge and the total negative charge in each formula with this many ions? Give two examples of these formulas.

    asked on September 23, 2018
  30. math

    Is tan(90-theta) the same as tan(theta)???

    asked on April 8, 2018
  31. math

    Show that the surface area of a sphere is two thirds of the total surface area of any cylinder circumscribed around the sphere (the sphere therefore touches both bases of the cylinder as well as its lateral surface).

    asked on July 30, 2018
  32. math

    Show that any dilation transforms any figure into a similar figure.

    asked on August 19, 2017
  33. math

    Find a vector of length 3 that is perpendicular to [2,1,-2]

    asked on August 15, 2017
  34. chemistry

    How do you write the chemical formula for ammonium acetate and ammonium hydrogen sulfate?

    asked on September 8, 2018
  35. math

    Explain the notation M^-1 used for the inverse of a square matrix M. I thought M^-1 would be a normal inverse matrix except the numbers would be vertically switched like in fractions...? Not sure though.

    asked on August 12, 2018
  1. chemistry

    Ohh okay, all these answers make sense. Thank you so much!

    posted on March 18, 2019
  2. chemistry

    how do I calculate the heat of fusion of ice??

    posted on January 14, 2019
  3. Chemistry

    Okay got it thank you!

    posted on January 14, 2019
  4. math

    Okay, that makes so much more sense. Thank you so much!

    posted on November 7, 2018
  5. math

    Ohh okay got it thank you!

    posted on September 15, 2018
  6. chemistry

    right thank you!

    posted on September 13, 2018
  7. math

    okay, that makes sense. thank you!

    posted on August 10, 2018
  8. math

    sorry my response is so late... I tried solving it again and I got the equation y=2+4sin(3x). I got the two because the graph is shifted 2 units up and I got the four from the graph being stretched vertically 4 times. Then I plugged in the point (30,6)

    posted on August 9, 2018
  9. math

    what if you had a maximum point let's say (30,6) and a y-int of (2,0) and you had to find the equation of the graph? I get how to find the other variables just not m.

    posted on August 8, 2018
  10. math

    okay thanks! also is there any way to simplify (cos^4(theta) - sin^4(theta)) / (cos^2(theta)*sin(theta))

    posted on April 8, 2018