Mass of Zn 2.44 g Mass of Cu 0.063 g The mass of Zn and the mass of Cu in a coin are given in the table. How is the number of moles of Zn in the coin determined? A By multiplying 0.063 g by 65.38 g/mol By multiplying 2.44 g by 65.38 g/mol By dividing 2.44 g by 65.38 g/mol By dividing 65.38 g mol by 2.44g

Suppose you have a sample of sodium weighing 12.40 g. How many atoms of sodium are present in the sample? What mass of potassium would you need to have the same number of potassium atoms as there are sodium atoms in the sample of sodium? atoms of sodium g of potassium

CHEMWORK With the advent of techniques such as scanning tunneling microscopy, it is now possible to "write" with individual atoms by manipulating and arranging atoms on an atomic surface. a. If an image is prepared by manipulating iron atoms and their total mass is 1.30 x 10-20 g, what number of iron atoms were used? 1 mole = 6.022 x 1023 atoms Fe atoms b. If the image is prepared on a platinum surface that is exactly 22 platinum atoms high and 13 platinum atoms wide, wha is the mass (grams) of the atomic surface? g Pt c. If the atomic surface were changed to ruthenium atoms and the same surface mass as determined in part b is used, what number of ruthenium atoms is needed to construct the surface? Ru atoms

How many moles of ammonia contain 1.51 x 1024 NH3 molecules? A) 2.51 mol B) 0.399 mol C) 0.251 mol D) 3.99 mol E) 25.1 mol  How many molecules of methane gas, CH4, have a mass equal to 3.20 g? A) 1.20 x 1023 molecules B) 1.20 x 1024 molecules C) 1.93 x 1024 molecules D) 3.01 x 1023 molecules E) 3.01 x 1024 molecules

a. A 9.475 gram sample of copper is heated in the presence of excess chlorine. A metal chloride is formed with a mass of 20.05 g. Determine the empirical formula of the metal chloride. b. A 23.11 gram sample of manganese is heated in the presence of excess bromine. A metal bromide is formed with a mass of 90.32 g. Determine the empirical formula of the metal bromide.

Calculate the mass (in grams) of 4.59x1024 atoms of Cu. Calculate the number of atoms of Cu in 52.1 g of Cu. g atoms

Which of these are correct/ true? A. 1 mole of He has the same amount of atoms than 1 mole of CaB. Avogadro’s number is the number of particles it takes to make 1 mole, whichis 6.022 x 1023 particlesC. The molar mass of NaCl is the same as the molar mass of ClD. The molar mass of Ar (arsenic) is 74.922 g/mo

What is the mass of oxygen atoms in 0.305 moles of Fe(CO)5 ?A. 17.0 gB. 59.7 gC. 24.4 gD. 4.88 g

Name each compound, and then calculate its mass. Express this value in scientific notation.

A 5.70 g mixture contains both lithium fluoride, LiF, and potassium fluoride, KF. If the mixture contains 3.53 g fluorine, what is the mass of the KF in the mixture?