EOT COVARAGE

Explain the law of conservation of mass?

• mass neither be created nor be destroyed The overall mass of the reactant is equal to the  over all mass of the products.

• mass is create and destroyed. the overall mass of the reactant is equal to the over all mass of products

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Describe the purpose of coefficient in the chemical equations?

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•  it describes the total number of reactant in the chemical equation

• Coefficient describes the number of units of each reactant or products in the chemical equations.

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How can you tell whether a chemical equation is balanced or not balanced?

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• an equation is balanced number of atoms of one side is not same in the equation.

• An equation is balanced  if the number of  atoms of each elements of the same on the both side of the equation

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Balance this equation-NaOH(aq)+CaBr2(s)------->Ca(OH)2(s) +NaBr(aq)

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• Ca(OH)2(s)+2NaBr(aq)

• CaOH2 +2Na Br

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What happens in a combustion reaction?

• A substance combines with oxygen to produce energy

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• it is an insoluble compound that comes out of solution during the type of reaction

compare and contrast  oxidation and reduction

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• oxidation involves loss of electron and reductions involves gain of electron.

• reduction involves loss of electron and oxidation is the gain of electron.

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Consider the following reaction Ba(NO3)2(aq)+K2SO4(aq)---->BaSO4(s) +2KMNO3(aq).Which substance is the precipitate? What type of reaction is this?

• BaSO4, Double displacement reaction

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• KMNO4,  Combustion reaction

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Why is a log fire is considered to be an  exothermic reaction?

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• The reaction of the oxygen in the air   with  the carbon compounds in the log releases heat and light. the release of thermal energy means the reaction is exothermic

• the chemical reaction that release energy and that required break the bond n the reaction