Chemistry test 2
|Which of these compounds is not a base|
|What is the formula for the compound nitrogen monoxide?||NO|
|What is the formula for the compound tetraphosphorus decoxide||P4O10|
|What is the formula for the compound methane||CH4|
|What is the name of the acid whose formula is HI?||Hydroiodic acid|
|What is the formula for chlorous acid?||HClO2|
|What is the name of the acid whose formula is H2CO3?||carbonic acid|
|What is the formula for sulfurous acid?||H2SO3|
|What is the name of the covalent compound CCl4||carbon tetra chloride|
|What is the name of the covalent compound N2O5?||dinitrogen pentoxide|
|What is the name for the compound NO2||nitrogen dioxide|
|chemical formula for quartz||SiO2|
|How many oxygen atoms are in 2.80 g of quartz?||number of O atoms = 5.62×1022|
*find molar mass, divide 2.80 by molar mass. use avogadros number to get rid of moles. and multiply by 2
|What is the formula weight of Mg(NO3)2?||148.3 amu|
|Calculate the formula weight of ethanol, C2H5OH||46.1 amu|
|How much does one sucrose molecule weigh in grams?|
Express your answer with the appropriate units.
|mass of one molecule of sucrose = 5.68×10−22 g|
*342 g/mol, divided by avogadros number
|A certain ionic compound is made entirely of aluminum and oxygen.||Al2O3|
|What is the mass percentage of each element in the compound Al2O3||52.9% and 47.1%|
find mollar mass. and divide
|Enter the subscripts for C, H, and O, respectively, separated by commas (e.g., 5,6,7).||1,2,1|
|The molecular formula mass of this compound is 150 amu . What are the subscripts in the actual molecular formula?|
Enter the subscripts for C, H, and O, respectively, separated by commas (e.g., 5,6,7).
|A hydrocarbon is a compound that contains mostly carbon and hydrogen. Calculate the percent composition (by mass) of the following hydrocarbon: C 5 H 12 .|
Enter the percentages of carbon and hydrogen numerically to four significant figures, separated by commas.
mass percent=mass of element / mass of compound×100%
|A certain metal hydroxide, M(OH)2, contains 32.8% oxygen by mass. What is the identity of the metal M?|
Enter the full name of the element.
Mass of oxygen32.8g
moles of oxygen 2.05(/16)
moles of hydrogen2.05(= in formula)
mass of hydrogen 2.05g (*1)
Mass of metal 65.15g (by difference from 100)
moles of metal 1.03(O /2)
so we have 1.03 moles of metal in 65.15 g
mass of 1 mole = 63.56 g
|Give the empirical formula of dimethylmercury||HgC2H6|
|How many molecules are contained in a 7.75-g sample of dimethylmercury?|
Express your answer in molecules to three significant figures.
|What is the percentage of mercury (by mass) in the sample?|
Express your answer as a percent to four significant figures.
|mass percent of Hg = 86.96 %|
|What is the empirical formula for the compound P4O6?||P2O3|
|An unknown compound contains only carbon, hydrogen, and oxygen (CxHyOz). Combustion of 5.50 g of this compound produced 8.07 g of carbon dioxide and 3.30 g of water.|
|How many grams of each element are in this sample?|
Enter the number of grams of carbon followed by the number of grams of hydrogen, separated by a comma (e.g., 30.0,70.0).
|mass of C, mass of H = 80.0,20.0 g|
|How many moles of each element are in this sample?|
Enter the number of moles of carbon followed by the number of moles of hydrogen, separated by a comma.
|How many moles of carbon, C, were in the original sample?|
Express your answer to three significant figures and include the appropriate units
|How many moles of hydrogen, H, were in the original sample?|
Express your answer to three significant figures and include the appropriate units.
|If 5.50 g of the unknown compound contained 0.183 mol of C and 0.367 mol of H, how many moles of oxygen, O, were in the sample?||.183 mol|
|What is the empirical formula of a substance that contains 0.183 mol of carbon, 0.367 mol of hydrogen, and 0.183 mol of oxygen?||CH2O|
|Determine the molecular formula for the unknown if the molecular mass is 60.0 amu and the empirical formula is CH2O.||C2H4O2|
|The figure (Figure 1) shows the reaction of element A (lavender spheres) with element B (tan spheres). Write the balanced chemical equation for this reaction in terms of A and B.||2A+3B2→2AB3|
|Phosphoric acid reacts with magnesium hydroxide to produce magnesium phosphate and water via the following reaction:|
Balance the equation, then enter the coefficients, in order, in the answer box.
Enter four integers separated by commas.
|You carefully weigh out 17.00 g of CaCO3 powder and add it to 68.85 g of HCl solution. You notice bubbles as a reaction takes place. You then weigh the resulting solution and find that it has a mass of 78.88 g . The relevant equation is|
Assuming no other reactions take place, what mass of CO2 was produced in this reaction?
|Based on the mole ratio you determined in Part C, what is the empirical formula of this compound?|
Express your answer as a chemical formula