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Law of Conservation of Matter (mass)

Law of Conservation of Matter (mass). How can you demonstrate the Law of Conservation of Matter in a chemical reaction?. When we take calcium chloride (CaCl 2 ) and combine it with sodium sulfate (Na 2 SO 4 ), they will chemically react.

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Law of Conservation of Matter (mass)

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  1. Law of Conservation of Matter (mass)

  2. How can you demonstrate the Law of Conservation of Matter in a chemical reaction?

  3. When we take calcium chloride (CaCl2) and combine it with sodium sulfate (Na2SO4), they will chemically react. • The atoms will rearrange to form calcium sulfate (CaSO4) and sodium chloride(NaCl). • Notice that in the first picture the calcium chloride (CaCl2) and sodium sulfate (Na2SO4) are in a sealed container but they have not been mixed. • The substances that you start with are called the reactants.

  4. In the middle picture, the flask is inverted so that the two chemicals can mix. • When they mix, they react together. In the last picture, • we now have 2 new substances and these are called products.

  5. How do you apply the Law of Conservation of Matter to balance chemical equations? • The Law of Conservation of Mass states that mass is neither created nor destroyed. • Therefore there must be the same number and type of each atom on the reactant side and product side so that there will be the same mass on each side of the equation.

  6. Coefficients, reactants, products

  7. Numbers at the base of each element are called subscripts. They represent the number of atoms. Students often mix up coefficients and subscripts. Subscripts represent atoms that are bonded together whereas coefficients represent how many molecules or atoms you have.

  8. How are chemical reactions classified?Reactions can be classified as synthesis,decomposition, single replacement, or double replacement.

  9. How do we balance chemical equations? • By placing a blank in front of each substance, this helps you to know where the coefficients can be placed. • ___ Na + ___Cl2 ___ NaCl Put coefficients in the blank so that the equation has the same number and kind atoms on each side. For example, there are two chlorine atoms on the left but only one on the right side so we will put a 2 as a coefficient on the NaCl side. ___ Na + ___Cl2 _2__ NaCl

  10. This is a balanced synthesis equation. Remember you only change the coefficients to balance an equation – NEVER the subscripts! • Now we have two Cl atoms on each side. We also have two Na atoms on the product side and only one on the left side. So let’s put a coefficient of two in front of the Na. • _2__ Na + ___Cl2 _2__ NaCl

  11. How can you use atomic masses to prove the Law of Conservation of Mass? Mass is conserved. There are 44 g on the reactant side and on the product side. No matter has been created nor destroyed.

  12. Formative Assessment Matter is not created or destroyed • 1.What does the Law of Conservation of Matter state? • 2. In a chemical reaction the substances at the beginning are called ___ • 3. In a chemical reaction the substances at the end are called ____? • 4. What happens to the mass of the substances after the chemical is over? • 5. In a chemical equation what do the coefficients represent? • 6. In a chemical equation what do the subscripts represent? reactants products Remains the same molecules/atoms atoms

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