Suppose that 4.1 mol NO2 and 0.80 mol H2O combine and react completely. Which reactant is in excess? Express your answer as a chemical formula.

Consider the fictional element A (which has a molar mass of 7.00 g/mol) and the fictional element D (which has a molar mass of 13.00 g/mol). Suppose that 16.20 grams of an unknown hydrate of A2D are heated until a constant mass of 5.40 grams is reached. How many waters are in the empirical formula of the hydrate? (For example, if the empirical formula were Na2SO4 ⋅ 10 H2O, your answer would be 10.)

Aspirin can be made in the laboratory by reacting acetic anhydride (C4H6O3C4H6O3) with salicylic acid (C7H6O3C7H6O3) to form aspirin (C9H8O4C9H8O4) and acetic acid (C2H4O2C2H4O2). The balanced equation isC4H6O3+C7H6O3→C9H8O4+C2H4O2C4H6O3+C7H6O3→C9H8O4+C2H4O2In a laboratory synthesis, a student begins with 3.10 mLmL of acetic anhydride (density=1.08gml−1density=1.08gml−1) and 1.23 gg of salicylic acid. Once the reaction is complete, the student collects 1.22 gg of aspirin.    Determine the percent yield of aspirin for the reaction. Express your answer using three significant figures.

Solid phosphorus  P and chlorine  Cl2  gas react to form solid phosphorus pentachloride  PCl5 . Suppose you have 9.0 mol of P and 1.0 mol of Cl2 in a reactor.   Could half the P react?   yes     no   If you answered yes, calculate how many moles of PCl5 would be produced after half the P was used up. Round your answer to the nearest 0.1 mol . mol

Consider the reaction: N2(g) + 202(g) → 2NO2(g) 0.250 mol of N2(g) is reacted with 0.300 mol of O2(g). Calculate the amount of excess reagent in moles remains assuming complete reaction. [Hint: lIdentify the excess reagent first.] Select one: a. 0.150 mol of excess reagent remains. b. 0.200 mol of excess reagent remains. C. 0.050 mol of excess reagent remains. d. 0.100 mol of excess reagent remains.

In a reaction vessel, 15 mo! of P4 and 35 mol of Cl2 react. Determine which substances will be present in the con￾tainer after the reaction goes to completion and how many moles of each substance is present.

Solid phosphorus  P and chlorine  Cl2  gas react to form solid phosphorus pentachloride  PCl5 . Suppose you have 7.0 mol of P and 2.0 mol of Cl2 in a reactor.   Calculate the largest amount of PCl5  that could be produced. Round your answer to the nearest  0.1   mol .

Aspirin, C9H8O4, is prepared by reacting salicylic acid, C7H6O3, with acetic anhydride, C4H6O3, in the reaction shown below (already balanced for you):   salicylic acid +   acetic anhydride      →    aspirin +        water   2 C7H6O3   +      C4H6O3   →        2 C9H8O4 +      H20   A student is asked to prepare 85.0 g of aspirin.  How many grams of C4H6O3 should she use?

For every one molecule of NaHCO3(s) there is one molecule of CO2(g) that forms:  NaHCO3(s) + CH3CO2H(aq) --> CO2(g) + H2O(l) + NaCH3CO2(aq) This means that if we know how many moles of gas we need, we need the same number of moles of sodium bicarbonate to produce it. Now, we need something to fill with gas. I'll be filling a 1-quart sealable plastic bag. 1 quart is 946 mL (0.946 L). We can use the ideal gas law to determine how much gas (in moles) is needed to fill 946 mL. Remember there are four variables for the ideal gas law. Ideal Gas Law:    PV = nRT P = pressure: typically 715 mm Hg in Spokane  <-- unit dictates which R to use V = volume: 1 quart bag = 0.946 L   <-- must be in Liters T = room temperature: 20 °C in my lab, +273 = 293 K <-- must be Kelvin n = moles: what we are solving for I used atmospheric pressure in mm Hg, so I'll have to pick the R value with "mm Hg" in the units: R = 62.4 L × m m H g K × m o l Now, use these values to calculate how many moles of…

A 13.2010g sample of hydrated zinc sulfate, ZnSO4 • xH2O), was strongly heated until no further change in mass was recorded. The final mass of solid product was found to be 7.3997g. On heating, all of the water of crystallization had evaporated, as shown by the equation: ZnSO4 • xH2O -> ZnSO4 + xH2O  Calculate the number of moles of water of crystallization in the sample. Write in a padpaper and show the complete solution