What is the mass, in grams, of 1.40×1021 molecules of aspirin, C9H8O4C9H8O4? Express your answer using three significant figures.

In an experiment, zinc chlorate decomposed according to the following chemical equation.Zn(ClO3)2 → ZnCl2 + O2(Molar mass of Zn(ClO3)2 = 232.29 g/mol; ZnCl2 = 136.286 g/mol; O2 = 31.998 g/mol)If the mass of zinc chlorate was 150 grams, which of the following calculations can be used to determine the mass of oxygen gas formed?    (150 × 1 × 232.29) ÷ (31.998 × 3) grams  (150 × 3 × 232.29) ÷ (31.998 × 1) grams  (150 × 1 × 31.998) ÷ (232.29 × 3) grams orr (150 × 3 × 31.998) ÷ (232.29 × 1) grams

39.7 mL of a 0.117 M Na2CO3 solution completely react with a 0.150 MHNO3 solution according to the following balanced chemical equation: Na2CO3(aq)+2HNO3(aq)→2NaNO3(aq)+CO2(g)+H2O(l) What mass (in grams) of carbon dioxide is formed? Express your answer with the appropriate units.

What is the mass of 3.5 x 10^-3 molecules of copper (II) carbonate? Use correct significant figures and units.

A student finds that they have 0.2545 g of NH4Cl, 1.1502 g of NaCl, and 1.0181 g of SiO2. Calculate the percent gained or lost during this experiment if the initial mass of the mixture was 2.5537 g.

Calculate the following to the proper significant figures:  The molecular mass of iron(II) hydroxide.  The number of moles in 145g of MgCl2 The volume of 25.0g of steam at STP(steam is gaseous water)  The concentration of a solution of table salt (NaCl) if 12g is dissolved in 1.5L of water

1.) What is the molar mass for aluminum sulfate? Please use the atomic masses on the periodic table. Express your answer with the correct significant figures and units for molar mass. Mass Choices:  123.05 342.17 6.02 x 10^23 273.08 Unit Choices:  mol mol/g g g/mol 2.) How many grams are there in 5.699 moles of copper, Cu?  Express your answer with the appropriate significant figures and units.  0.08968 g/mol Cu 362.2 g/mol Cu 362.2 g Cu 0.08968 g Cu

2 NaOH(aq) + H2C2O4 = 2H2O(s) Na2C2O4(aq) + 4 H2O(l)  Calculate the mass of H2C2O4.2H2O required in the standardization.

A chemist adds 240.0 mL of a 1.1 mol/L sodium thiosulfate (Na2S2O3) solution to a reaction flask. Calculate the mass in grams of sodium thiosulfate the chemist has added to the flask. Round your answer to 2 significant digits. g x10 × ⑤

Aspirin can be prepared from salicylic acid (C7H6O3), which has a molar mass of 138.12 g/mol, and acetic anhydride (C4H6O3), which has a molar mass of 102.04 g/mol. The density of acetic anhydride is 1.082 g/mL. C7H6O3+C4H6O3⟶C9H8O4+C2H4O2 What is the yield, in grams, of aspirin (C9H8O4), which has a molar mass of 180.15 g/mol, possible when reacting 2.18 g of salicylic acid with 1.05 mL of acetic anhydride?