Chapter 2 Atoms 9 10 13 To find neutrons subtract mass number from amount of protons mass number Sodium 25 has 25 nucleons o Subtract 11 mass number from 25 14 protons Neutral atom protons and electrons are equal Dilution more solvent is added so that the volume increases and the concentration of the solute decreases Calculation Dilutions the initial and diluted solution the number of particles of solute are the same and the concentrations and volumes are related by the following equations C1V1 C2V2 Concentrated diluted Prepare Initial must be higher C1 w v V1 C2 w v V2 goal C1V1 C2V2 V2 V1C1 C2 Ex 10 09 X60 015 1 5 Density Density relates to the mass of an object m v 77 1 4 55 x Gravity Specific gravity unitless Numerically equal to density Density of substance g ml Density of water at the same temp g ml 1 Temperature How hot and cold Average kinetic energy of sample Not dependent on the size of the substance or number of molecule Convert o Kelvin o Celcius o Farenheit Heat Transfer of energy between particles o Associated with motion of particles o Transfers spontaneously from high to low o Temperature is reflection of kinetic energy of substance o Heat is energy and can be quantified Not the same as temperature Heating curve Changes of state of solid as heated Uses sloped lines to show and increase in temperature Uses plateaus to indicate a change of state Energy 4 184 joules J 1 calorie 1kj 1000 J 1 kilocalorie kcal 1000 calories Large C 1 Cal 1000 calories 1 Cal 1 kcal 1 Cal 4184 J 1 Cal 4 184 kj Caloric value of food Caloric values for foods indicte the number of kj or kcal provided for 1 gram of food Example 12 g of carbohydrates 9 g of fat 5 g of protein 4 12 48 kcal 9 9 81 kcal 5 4 20 kcal 149 kcal total Elements Building blocks of matter Gold carbon aluminum Elements are pure substances that cannot be separated into simpler substances by ordinary laborotry processes Metals found on the left side of the table Nonmetals found on the right side of the table MetalloidsNeed to know ab carbon hydrogen nitrogen oxygen phosphorus sodium potassium calcium magnesium iron zinc chlorine bromine fluorine sulfur zinc and helium Groups go down similar chemical properties Periods horizontal Groups hav common names share chemical properties Atomic Theory All matter is composed of atoms The atoms of a given element differ from the atoms of all other elements Chemical compounds consist of atoms combined with specific rations only whole atoms can combine Chemical reactuons change only the way atoms are combined in compounds Atoms Protons Electrons Neutrons Rutherford Gold Foil experiment Beams of particles into gold foil Once atoms hit another they will deflect Indicated that positive charge is concentrated o Nucleus o Protons got deflected Lots of empty space o Baseball field atom o Pea nucleus Nucleus bulk of mass Atoms Masses Masses of atoms and subatomic particles are expressed on a relative mass scale The basis for the scale is an atom of carbon that contains 6 protons and 6 neutrons This carbon atom is assigned a mass of exactly 12 atomic mass units or DALTONS Atomic number z Number above symbol Equal to number of protons in atom An atom of an element is electrically neutral the net charge of an atom is ZERO has an equal number of protons and electrons Mass number A Represents the number of particles in the nucleus sum of protons and neutrons mass number is not in periodic table Protons never change due to strong bonds electrons do Neutrons sometimes change not a big deal isotopes Electrons change big deal