Identify which statement is TRUE. Avogadro's constant is 3.00 × 108 per mole. There are 6.02 x 1023 atoms in one mole of helium. Atomic mass is measured in units of g/mol. The molar mass of hydrogen is 1.01 u

Boron forms an extensive series of compounds with hydrogen, all with the general formula BxHy. To analyze one of these compounds, you burn it in air and isolate the boron in the form of B2O3 and the hydrogen in the form of water. You find that 0.1482 g BxHy gives 0.4221 g B2O3 when burned in excess O2. Determine the empirical I formula of BxHy.

Consider the chemical reaction 2 S + 3 O2 → 2 SO3. If the reaction is run by adding S indefinitely to a fixed amount of O2, which of these graphs best represents the formation of SO3? Explain your choice.

The sugar sucrose, which is present in many fruits and vegetables, reacts in the presence of certain yeast enzymes to produce ethanol and carbon dioxide gas. Balance the following equation for this reaction of sucrose. C12H22O11(aq) + H2O(l) C2H5OH(aq) + CO2(g)

4.69 The pictures below show a molecular-scale view of a chemical reaction between H2 and CO to produce methanol, CH3OH. The box on the left represents the reactants at the instant of mixing, and the box on the right shows what is left once the reaction has gone to completion. Was there a limiting reactant in this reaction? If so, what was it? Write a balanced chemical equation for this reaction. As usual, your equation should use the smallest possible whole number coefficients for all substances.

Hydrogen cyanide is produced industrially from the reaction of gaseous ammonia, oxygen, and methane: 2NH3(g)+3O2(g)+2CH4(g)2HCN(g)+6H2O(g) If 5.00 103 kg each of NH3, O2, and CH4 are reacted, what mass of HCN and of H2O will be produced, assuming 100% yield?

The molecular formula of acetylsalicylic acid (aspirin), one of the most commonly used pain relievers, is C9H8O4. a. Calculate the molar mass of aspirin. b. A typical aspirin tablet contains 500. mg C9H8O4. What amount (moles) of C9H8O4 molecules and what number of molecules of acetylsalicylic acid are in a 500.-mg tablet?

You take 1.00 g of an aspirin tablet (a compound consisting solely of carbon, hydrogen, and oxygen), burn it in air, and collect 2.20 g CO2 and 0.400 g H2O. You know that the molar mass of aspirin is between 170 and 190 g/mol. Reacting 1 mole of salicylic acid with I mole of acetic anhydride (C4H6O3) gives you 1 mole of aspirin and 1 mole of acetic acid (C2H4O2). Use this information to determine the molecular formula of salicylic acid.

The space shuttle environmental control system handles excess CO2 (which the astronauts breathe out; it is 4.0% by mass of exhaled air) by reacting it with lithium hydroxide, LiOH, pellets to form lithium carbonate, Li2CO3, and water. If there are seven astronauts on board the shuttle, and each exhales 20. L of air pee minute, how long could clean air be generated if there were 25,000 g of LiOH pellets available for each shuttle mission? Assume the density of air is 0.0010 g/mL.

DDT (molar mass = 354.49 g/mol) was a widely used insecticide that was banned from use in the United States in 1973. This ban was brought about due to the persistence of DDT in many different ecosystems, leading to high accumulations of the substance in many birds of prey. The insecticide was shown to cause a thinning of egg shells, pushing many birds toward extinction. If a 20-L drum of DDT was spilled into a pond, resulting in a DDT concentration of 8.75 105 M, how long would it take for the levels of DDT to reach a concentration of 1.41 107 M (a level that is generally assumed safe in mammals)? Assume the decomposition of DDT is a first-order process with a half-life of 56.0 days.