Determine whether the statements given below are true or false. (a) The mass of an atom can have the unit mole. (b) In N204, the mass of the oxygen is twice that of the nitrogen. (c) One mole of chlorine atoms has a mass of 35.45 g. (d) Boron has an average atomic mass of 10.81 amu. It has two isotopes, B-10 (10.01 amu) and B-11 (11.01 amu). There is more naturally occurring B-10 than B-11. (e) The compound C 6 H 12 O 2 N has for its simplest formula C 3 H 6 ON 1/2 . (f) A 558.5-g sample of iron contains ten times as many atoms as 0.5200 g of chromium. (g) If 1.00 mol of ammonia is mixed with 1.00 mol of oxygen the following reaction occurs, 4NH 3 ( g ) + 5O 2 ( g ) → 4NO ( g ) + 6H 2 O ( l ) All the oxygen is consumed. (h) When balancing an equation, the total number of moles of reactant molecules must equal the total number of moles of product molecules.
Determine whether the statements given below are true or false. (a) The mass of an atom can have the unit mole. (b) In N204, the mass of the oxygen is twice that of the nitrogen. (c) One mole of chlorine atoms has a mass of 35.45 g. (d) Boron has an average atomic mass of 10.81 amu. It has two isotopes, B-10 (10.01 amu) and B-11 (11.01 amu). There is more naturally occurring B-10 than B-11. (e) The compound C 6 H 12 O 2 N has for its simplest formula C 3 H 6 ON 1/2 . (f) A 558.5-g sample of iron contains ten times as many atoms as 0.5200 g of chromium. (g) If 1.00 mol of ammonia is mixed with 1.00 mol of oxygen the following reaction occurs, 4NH 3 ( g ) + 5O 2 ( g ) → 4NO ( g ) + 6H 2 O ( l ) All the oxygen is consumed. (h) When balancing an equation, the total number of moles of reactant molecules must equal the total number of moles of product molecules.
Capsaicin, the compound that gives the hot taste to chili peppers, has the formula C18H27NO3.(a) Calculate its molar mass.(b) If you eat 55 mg of capsaicin, what amount (moles) have you consumed?(c) Calculate the mass percent of each element in the compound.(d) What mass of carbon (in milligrams) is there in 55 mg of capsaicin?
(a) Atoms are very small compared to objects on the macroscopic scale. The radius of a nickel atom is 125 pm. What is this value in meters
and in centimeters?
cm
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(b) The mass of a single nickel atom is 9.75×10 g. Suppose enough Ni atoms were lined up like beads on a string to span a distance of
31.3 cm (12 inches). How many atoms would be required?
atoms
What mass in grams of Ni would be used?
Could you weigh out this amount of nickel using a typical laboratory balance?
(c) Taking the density of nickel metal to be 8.91 g/cm, calculate the mass of metal needed to form a piece of Ni wire with the same length
as the distance in b, but with a diameter of 1.00 mm. Hint: The volume of a cylinder is n times its radius squared times its height. (V = nr
h)
How many nickel atoms does this represent?
atoms
Obtain an estimate for the number of atoms in the universe. Make the following assumptions: (a) All of the atoms in the universe are hydrogen atoms in stars. (This is not a ridiculous assumption because over threefourths of the atoms in the universe are in fact hydrogen. Gas and dust between the stars represent only about 15% of the visible matter of our galaxy, and planets compose a far smaller fraction.) (b) The sun is a typical star composed of pure hydrogen with a density of 1.4 g/cm^3 and a radius of 7x10^8 m. (c) Each of the roughly 100 billion stars in the Milky Way galaxy contains the same number of atoms as our sun. (d) Each of the 10 billion galaxies in the visible universe contains the same number of atoms as our Milky Way galaxy.
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Step by Step Stoichiometry Practice Problems | How to Pass ChemistryMole Conversions Made Easy: How to Convert Between Grams and Moles; Author: Ketzbook;https://www.youtube.com/watch?v=b2raanVWU6c;License: Standard YouTube License, CC-BY