January 12, 2018 F = 1 g/cubic centimeters G = .8333… g/cubic centimeters H = 2.75 g/cubic centimeters J = .8 g/cubic centimeters So the correct answer is H

I can count the # of atoms in a chemical equation. Yesterday we learned how to balance a chemical equation using the mass measurements. Recall: If 23 g of sodium reacts with 19 grams of chlorine, it will produce ________ of sodium chloride? 42 grams Today we’re going to look at actual chemical equations. Do we remember what the starting materials are called? reactants Do we remember what the final substances are called? products Chemical equations describe chemical reactions. I can count the # of atoms in a chemical equation.

I can count the # of atoms in a chemical equation. A chemical equation shows the formulas and symbols of the reactants & the products they create. A chemical equation also documents how much of each reactant went into the process and how much product came out. A chemical equation is similar to a recipe. It lists the ingredients needed to make a specific kind of cookie & it will usually tell you how many cookies can be made from the recipe. I can count the # of atoms in a chemical equation.

I can count the # of atoms in a chemical equation. Let’s see what Tim & Moby know about balancing equations. https://www.brainpop.com/science/matterandchemistry/chemicalequations/ So, in a chemical reaction the atoms may break bonds with each other and make new bonds with different atoms, but NO NEW ATOMS will be destroyed and NO NEW ATOMS will be created. The total mass is unchanged! Let’s see how this works… I can count the # of atoms in a chemical equation.

Chemical equations contain both subscripts AND coefficients I can count the # of atoms in a chemical equation.

If there is no subscript, then there is only one atom of that element. So in this molecule there is one atom of S and two atoms of O.

Practice time…subscripts a) nitrogen(1), hydrogen(5), oxygen(1)=7 atoms b) carbon(6), hydrogen(12), oxygen(6)=24 atoms c) aluminum(1), chlorine(3)=4 atoms d) carbon(1), oxygen(2)=3 atoms e) copper(1), oxygen(1)=2 atoms f) hydrogen(1), chlorine(1)=2 atoms g) magnesium(1), chlorine(2)=3 atoms h) zinc(1), carbon(1), oxygen(3)=5 atoms I can count the # of atoms in a chemical equation.

This shows that there are 4 sulfur atoms & 8 oxygen atoms. If there is a coefficient in front of a molecules, that tells us how many sets of that entire molecule… 4SO2 = SO2 SO2SO2SO2 This shows that there are 4 sulfur atoms & 8 oxygen atoms.

Practice time…subscripts & coefficients 2NaOH 4KNO3 3Fe2O3 3H2O2 4HFSbF3 3Al2O3 4Li2O a) sodium(2), oxygen(2), hydrogen(2)=6 atoms b) potassium(4), nitrogen(4), oxygen(12)=20 atoms c) iron(6), oxygen(9)=15 atoms d) hydrogen(6), oxygen(6)=12 atoms e) hydrogen(4), fluorine(16), antimony(4)=24 atoms f) aluminum(6), oxygen(6)=12 atoms g) lithium(8), oxygen(4)=12 atoms If an element is in parentheses Ca3(PO4)2 it means the molecule in parentheses is a set. So this formula has 3 calcium and 2 sets of PO4 which mean 2 phosphorus and 8 oxygen for a total of 13 atoms. I can count the # of atoms in a chemical equation.

I can count the # of atoms in a chemical equation. Exit Ticket I can count the # of atoms in a chemical equation.