| A | B |
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| Bromide exists naturally as a mixture of bromide-79 and bromide-81 isotopes.An atom of bromide-79 contains how many protons,neutrons, and electrons? | 35 protons,44 neutrons, 35 electrons |
| The atomic mass of rhenium is 186.2 .Given that 37.1% of natural rhenium is rhenium-185, what is the other stable isotope of the element rhenium? | 189^(Re)75 where the 189 is superscripted and the 75 is subscripted. |
| Consider the element indium, atomic number 49, atomic mass 114.8g. The nucleus of an atom of indium-112 contains how many protons,neutrons and electrons? | 49 protons and 63 neutrons |
| Gallium consists of two isotopes of masses 68.95 amu with abundances of 60.16% and 39.84%, respectively. What is the average atomic mass of gallium? | 69.55 |
| Naturally occurring iron contains 5.82% of 54^(Fe)26 {the 54 is SUPERSCRIPTED and the 26 is SUBSCRIPTED) , 91.66% of 56^(Fe)26 , 2.19% of 57^(Fe)26 and o.33% of 58^(Fe)26. The respective atomic masses are 53.940 amu, 55.935 amu, 56.935 amu, and 57.933 amu. Calculate the average atomic mass of iron. | 55.85 amu |
| What is the mass of 7 atom(s) of copper in grams? | 7.39e-22g (That is, 7.39 x 10^-22 g) |
| Iron is biologically important in the transport of oxygen by red blood cells from the lungs to the various organs of the body.In the blood of an adult human, there are approximately 2.64e13 (or 2.64 x 10^13) red blood cells with a total of 2.90g of iron. On the average, how many iron atoms are present in each red blood cell? *****Note that the Molar Mass of Fe is 55.85g per mole****** | 1.18e9 (or 1.18 x 10^9) |
| Naturally occurring copper exists in two isotope forms,Cu-63 and Cu-65. The atomic mass of copper is 63.55 amu. What is the approximate natural abundance of Cu-63? | 70% |
| Naturally occurring element "X" exists in three isotopic forms: X-28 ( 27.977 amu, 92.21% abundance) , X-29 ( 28.976 amu, 4.70% abundance) , and X-30 ( 29.974 amu, 3.09% abundance ). Calculate the atomic weight of "X". | 28.09 amu |
| A sample of ammonia has a mass of 36.6g. How many molecules are in this sample? | 1.29e24 ( 1.29 x 10^24) |
| How many moles of hydrogen sulfide are contained in a 49.7 g sample of hydrogen sulfide gas? | 1.46 mol |
| What is the molar mass of ethanol, C2H5OH ? | 46.07 g/mol |
| What is the mass of 0.256 mole of the compound CH3Cl ? | 12.8 grams |
| ROUNDUP,a brand of herbicide manufactor by Monsanto, has the formula C3H8NO5P . How many moles of molecules are there in 592.9 g sample of ROUNDUP? | 3.507 moles |
| Phosphorus has the molecular formula P4 and sulfur has the molecular formula S8. How many grams of phosphorus contain the same number of molecules as 7.96 g of sulfur? | 3.84 grams |
| A given sample of xenon fluoride contains molecules of a single type XeFn, where n is some whole number. Given that 9.03 x 10^20 molecules of XeFn weigh 0.311 g, calculate n. | 4 |
| Phosphoric Acid can be prepared by reaction of sulfuric acid with "phosphate rock" according to the equation Ca3(PO4)2 + 3H2SO4 ----> 3CaSO4 + 2H3PO4 ...What is the molar mass of Ca3(PO4)2 ? | 310.18 g/mol |
| Phosphoric acid can be prepared by reaction of sulfuric acid with "phosphate rock" according to the equation: Ca3(PO4)2 + 3H2SO4 ----> 3CaSO4 + 2H3PO4 . How many oxygens are there in 7.16 ng of Ca3(PO4)2 ? | 1.11e14 (1.11 x 10^14) |
| What is the molar mass of Ca3(PO4)2 ? | 310.18 g/mol |
| How many grams are in a 5.690-mol sample of sodium hydroxide? | 227.6 g |
| How many atoms of hydrogen are present in 2.2g of water? | 1.5e23 (1.5 x 10^23) |
| What is the molar mass of cryolite ( Na3AlF6) ? | 210.0 |
| The molar mass of calcium phosphate, Ca3(PO4)2 , is what? | 310.2 g/mol |
| Between HCL, H2O , H2SO4 , H2S , and HF -----Which compound contains the highest percen by mass of hydrogen? | H2O |
