Questions asked by Amaya K.

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• The heat of vaporization of water is 40.66 kJ/mol. How much heat is absorbed when 2.87 g of water boils at atmospheric pressure?
  
• The specific heat of a certain type of metal is 0.128 J/(g·°C). What is the final temperature if 305 J of heat is added to 83.0 g of this metal initially at 20.0 °C?
  
• How to do you find delta H?
  
• A metal foil has a threshold frequency of 5.45× 1014 Hz. Which of the colors of visible light have enough energy to eject electrons from this metal?
  
• How many photons are produced in a laser pulse of 0.210 J at 535 nm?
  
• How many subshells are in the n = 3 shell? And How many orbitals are in the n = 5 shell?
  
• What is the volume?
  
• An unknown gas at 49.1 °C and 1.10 atm has a molar mass of 16.04 g/mol. Assuming ideal behavior, what is the density of the gas?
  
• A sample of Br2(g) takes 30.0 min to effuse through a membrane. How long would it take the same number of moles of Ar(g) to effuse through the same membrane?
  
• A gas mixture is made by combining 7.0 g each of Ar, Ne, and an unknown diatomic gas. At STP, the mixture occupies a volume of 16.60 L. What is the molar mass of the unknown gas?
  
• Lewis Structure?
  
• If He(g) has an average kinetic energy of 6670 J/mol under certain conditions, what is the root mean square speed of Cl2(g) molecules under the same conditions?
  
• A gaseous mixture contains 440.0 Torr of H2(g), 365.7 Torr of N2(g), and 88.7 Torr of Ar(g). Calculate the mole fraction, X, of each of these gases?
  
• Calculate the number of collisions per second of one hydrogen molecule at 24 °C and 2.00 bar. The diameter of a hydrogen molecule is 270 pm?
  
• Molar mass and density?
  
• Verify that each equation is an identity?
  
• Why can't the Pythagorean theorem be used to solve an oblique triangle?
  
• What is the smallest time t such that I = 4?
  
• Use the formula s = r#omega#t to find the value of the missing variable. Give an exact answer?
  
• What is the empirical formula of the unknown compound?
  
• Find the reference angle θ =2π3?
  
• Fill in the blank. Let θ be an angle in standard position, with (x, y) a point on the terminal side of θ and r = #sqrt(x^2 + y^2)≠ 0#?
  
• The terminal side of θ lies on a given line in the specified quadrant. Find the values of the six trigonometric functions of θ by finding a point on the line? Line y = 1/6x Quad: III
  
• A point in polar coordinates is given. Convert the point to rectangular coordinates? (0, −3π)
  
• Convert the polar equation to rectangular form? r = 3/9 cos θ − 8 sin θ
  
• Use DeMoivre's Theorem to find the indicated power of the complex number. Write the result in standard form. (Round terms to four decimal places.)?
  
• Use DeMoivre's Theorem to find the indicated power of the complex number. Write the result in standard form?
  
• Find the square roots of the complex number. (Enter your answers as a comma-separated list. Round terms to four decimal places.) ?
  
• Use DeMoivre's Theorem to find the indicated power of the complex number. Write the result in standard form?
  
• Use this formula to find all the solutions of the equation? #x^3# + 8 =0
  
• Find the exact value of the trigonometric function given that sin u = − 3/5 and cos v = − 8/17? (Both u and v are in Quadrant III.)
  
• Write the expression as the sine, cosine, or tangent of an angle?
  
• Prove the identity of #cos(3x + 3y) + cos(3x − 3y) = 2 cos 3x cos 3y#?
  
• A rectangular page is to contain 16 square inches of print. The margins on each side are 1 inch. Find the dimensions of the page such that the least amount of paper is used?
  
• Find the length and width of a rectangle that has the given perimeter and a maximum area? Perimeter: 164 meters
  
• Find two positive numbers that satisfy the given requirements. The sum of the first number squared and the second number is 60 and the product is a maximum?
  
• Find the length of a circular arc subtended by an angle of #π/6# rad, if the radius of the circle is 48 cm?
  
• Find all values of x in the interval [0, 2π] that satisfy the equation. (Enter your answers as a comma-separated list.)? 4 + 2 cos(2x) = 6 cos(x)
  
• Find all values of x in the interval [0, 2π] that satisfy the equation. (Enter your answers as a comma-separated list.)? 16 cos(x) + 8 sin(2x) = 0
  
• Find all values of x in the interval [0, 2π] that satisfy the equation. (Enter your answers as a comma-separated list.)? 18 cos(x) − 9 = 0