| A | B |
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| Define: Percent Composition | The percent by mass of each element in a compound. |
| Define: Empirical Formula | The simplest possible formula for a compound that indicated the smallest whole number ratio in a compound. |
| State: The Law of Definite Composition | A compopund always contains two or more elements combined in a definite proportion by mass. |
| What is the percent composition of NHO3 ? | H = 1.59%; N = 22.23%; O = 76,17% |
| Calculte the percent of water in MgSO4.7H2O | 51.16% |
| What does "a large dot followed by water molecules indicate ? | It indicates a "hydrated compound." |
| It was found that 11.57g of Fe combines with 4.43g of O. What is the empirical formula of the oxide ? | Fe2O4 |
| 1.40g of nitrogen is reacted to form 3.80g of oxide. What is the empirical formula of the oxide ? | N2O3 |
| A compound is found to be 36.2% Na and 25.3% S and 38.5% O. What is the empirical formula of the compound ? | Na2SO3 |
| If 11.57g of Fe compbines with 4.43g of O, what is the percent composition of the compound ? | Fe = 72.31%; O = 27.69% |
| A compound with an empirical formula of CH2 is found to have a molecular weight of 42g/mol. What is the true formula (molecular formula) ? | C3H6 |
| Calculate the percent composition of Ag2SO4 | Ag = 69.18%; s = 10.28%; O = 20.54% |
| What is the percent of water in Na2CO3.2H2O ? | 25.36% |
| What is the empirical formula of an oxide containing 49.5% manganese ? (Hint Oxide = compound of Mn with O) | Mn2O7 |
| What is the (a) percent of water (b) percent of oxygen for the hydrate MgSO4.2H2O ? | H2O = 23.04%; O = 61.38% |
| If 2.21 grams of strontium combines with 1.79 grams of chlorine to form a chloride, calculate the percent composition of the compound. | Cl = 44.75%; Sr = 55.25% |
| What is the empirical formula of a compound based on the following information: Fe = 63.5%; S = 36.5% | FeS |
| What is the empirical formula of a compound based on the following information: H = 0.83%; Mn = 45.8%; O = 53.4% | HmnO4 |
| What is the empirical formula of a compound based on the following information: C = 85.7%; H = 14.3% | CH2 |
| What is the empirical formula of a compound based on the following information: N = 25.9%; ) = 74.1% | N2O5 |
| What is the empirical formula of a compound based on the following information: K = 31.9%; Cl = 28.9%; O = 39.2% | KClO3 |
| What is the empirical formula of a compound based on the following information: C = 81.8%; H = 18.2% | C3H8 |
| 8.0g of iron when burned in air yields 11.44g oxide. What is the empirical formula of thei oxide ? | Fe2O3 |
| Given the empirical formula NO2 and a molecular weight of 92.0 g/mol, what is the molecular formula ? | N2O4 |
| A compound has the composition carbon 37.21%; hydrogen 7.83%; and chlorine 54.96%. If its MW is 385 g/mol, determine (a) the empirical formula (b) the molecular formula. | Empirical Formula = C2H5Cl; Molecular Formula = C12H30Cl6 |
| A hydrocarbon has a MW of 114 g/mol and has a composition of carbon 84.06% and hydrogen 15.94%. What is its (a) empirical formula (b) true formula ? | Empirical Formual = C4H9; True Formula = C8H18 |
| A hydrocarbon has a molecular weight of 78.0 g/mol and a composition of carbon - 92.31% and hydrogen - 7.69%. Find the (a) empirical formula and (b) molecular formula of the hydrocarbon. | Empirical Formula = CH; Molecular Formula of the hydrocarbon = C6H6 |
| Chloroform, CHCl3, is used in a laboratory experiment to extract bromine. What is the percent of chlorine in this compound ? | 89.09% |
| 1.30 grams of chromium reacts with 9.50 grams of iodine. What is the percent of chromium in this compound ? | 12.02% |
| Determine the empirical formula of a compound having the following composition: Ba = 80.1%; O = 18.7%; H = 1.2% | BaO2H2 or Ba(OH)2 |
| An organic compound has a gram molecular weight of 372 g/mol, and its composition is 38.6% carbon, 9.76% hydrogen, and 51.56% oxygen. Determine the empirical formula. | CH3O |
| An organic compound has a gram molecular weight of 372 g/mol, and its composition is 38.6% carbon, 9.76% hydrogen, and 51.56% oxygen. What is the true or molecular formula of this compound ?. | C12H36O12 |
