In 1912, research into the atomic mass of different elements ran into problems. Some elements seemed to have forms with different masses, but the same chemical properties. When they were from the same element, they had the same atomic number or number of protons. The mass differences were connected to their number of neutrons. The elements weren’t new, just different forms of previously identified elements.
In 1913, Frederick Soddy, a British chemist, called chemically identical elements with different atomic weights, isotopes, from the Greek word meaning “same place.” These were placed in the same spot on the Periodic Table.
Isotopes are different types of atoms with the same number of protons (i.e., atomic number), but different numbers of neutrons (i.e., atomic mass).
I'm having a hard time drawing out CH3CClHCH(NH2)CH3 and CH3NHCH(NHCH3)CHOHCH3 . the placment of the NH is putting me off. I'm meant to find draw out the mirror image of each of them and determine if they are enatiomers or diastermers (superimposible or not). if you can help me with drawing those two or all (just for confirmation) I will greatly appreciate it
Menthol is a crystalline substance with a peppermint taste and odor. When 1.67 g of menthol is dissolved in 25.0 g of cyclohexane, the freezing point of the solution is lowered by 8.91 °C. The freezing point and Kf constant for cyclohexane can be found here. Calculate the molar mass of menthol. in g/mol•
A solution is made by dissolving 0.594 mol of nonelectrolyte solute in 773 g of benzene. Calculate the freezing point, Tf, and boiling point, Tb, of the solution. Constants may be found here.
in degrees C
If your air conditioner is more than several years old, it may use the chlorofluorocarbon CCl2F2as the heat transfer fluid. The normal boiling point of CCl2F2 is − 29.8 °C, and the enthalpy of vaporization is 20.1 1 kJ/mol. The gas and the liquid have molar heat capacities of 11 7.2 J/mol ∙ K and 72.3 J/mol ∙ K, respectively. How much energy is evolved as heat when 20.0 g of CCl2F2 is cooled from + 40 °C to − 40 °C? I was told the answer is -4800 and I can't get my answer to match. Please show all the steps.•
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In science there are many key concepts and terms that are crucial for students to know and understand. Often it can be hard to determine what the most important science concepts and terms are, and even once you’ve identified them you still need to understand what they mean. To help you learn and understand key science terms and concepts, we’ve identified some of the most important ones and provided detailed definitions for them, written and compiled by Chegg experts.