(a) You can apply the following rule of three: if by stoichiometry of the reaction 1 mole of Fe₂O₃ produces 2 moles of Fe, 1.25 moles of Fe₂O₃ produces how many moles of Fe?įinally, 2.5 moles of Fe can be made from 1.25 moles of Fe₂O₃. (c) 665.5699 of Fe₂O₃ are needed to make 12.50 moles of H₂O.īy reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each product participate in the reaction: (b) 4.875 moles of H₂ are needed to make 3.75 moles of Fe. (a) 2.5 moles of Fe can be made from 1.25 moles of Fe₂O₃. Therefore, the density of the sugar solution will be 0.5 g.Ĭonsidering the reaction stoichiometry, you get: The volume is equal to the mass divided by the density, The mass is said to be equal to the volume multiplied by the density, Density also offers a very convenient method for obtaining the mass of a body from its volume or for obtaining the volume of a body from its mass. Density is also expressed in the terms of kilograms per cubic meter or in meter-kilogram-second or SI units.įor the common solids, liquids, and gases, the densities are mentioned in the textbooks and handbooks. The formula for density isĬommonly, density is expressed in units of grams per cubic centimeter.
So the density of the sugar solution will be 0.5 g.ĭensity is defined as the mass of a unit volume of a material substance. Therefore, the longest wavelength of the radiation will be 343.7 nmĪ 10.0 ml sample of a sugar solution has a mass of 5.0 g. Therefore, making λ (wavelength) the subject H is the plank's constant = 6.626 × 10^-34 J/sĬ is the speed of light in vacuum = 2.9998 × 10^8 m/sĮ is the energy of a photon = 5.778 x 10^-19 Joules Hence energy per bond = 5.778 x 10^-19 Joulesīreaking one bond requires energy equivalent to energy of a photon. Step 1: Energy required to break one bond (kJ/bond) We are required to find the longest wavelength with enough energy to break the C-C bonds. We know that 1 mole of bonds = 6.022 × 10^23 bonds. We are given 348 kJ/mol required to break carbon-carbon bonds. In this question we need to first use the concept of energy of a photon.Įnergy of a photon, E, is given by the formula, E = hf, where h is the plank's constant, f is the frequency.īut since, f is given by dividing speed, c, by wavelength, λ, then Longest wavelength = 343.7 nm Solution and Explanation: This means Marc arrived late for his dinner. Hence, it must have taken Marc 6 hours and 40 minutes to get to his mom's house, meaning he arrived his mom's house at 18:40 (6:40 p.m). In order to get the actual time (in hours and minutes) spent on the road, the ".67" in the answer above will have to be converted to minutes because the clock is not represented in decimal places.Īfter the decimal, 100 will represent 60 minutes hence, The speed and distance are 45 mph and 300 miles respectively (as provided in the question). Speed (in mph) = distance (in miles) ÷ time (in hours) Marc needed to spend at most 6 hours on the road in order to get to his mom's house early. Marc left home 12:00 p.m, and his dinner was ready 6:00 p.m (18:00), he needed
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