An acidified solution was electrolyzed using copper electrodes. A constant current of 1.18 A caused the anode to lose 0.584 g after 1.52 3 103 s. (a) What is the gas produced at the cathode and what is its volume at STP? (b) Given that the charge of an electron is 1.6022 3 10219 C, calculate Avogadros number. Assume that copper is oxidized to Cu21 ions.
Chapter 5 Notes I. physical vs chemical changes A. physical: composition remains the same, change of state B. chemical: new substance is formed C. chemical reactions: involve chemical changes, atoms are rearranged II. chemical reactions- use formulas and symbols to represent chemical reaction “recipe” A. reactants on the left side of the equation, “ingredients” B. products on the right side of the equation, “cake” C. arrows separates reactants from products D. reactants must equal your products = balanced equation E. to balance an equation: 1.each individual compound must be written correctly before balancing 2. coefficients are used (numbers in front of the compound/element) 3. number of atoms of each element must be the same on both sides 4. coefficients must be in the lowest terms 5. watch out for diatomic elements BrINClHOF 6. practice F. symbols used= table 5.1 III. types of reactions A. combination/composition/synthesis: 2 or more elements or simple compounds to form one product A+B AB B. decomposition reaction: compound splits into two or more simple elements AB A+B C. single replacement: one element replaces another in a compound A+BC B+AC D. double replacement: two compounds reacting, negative and positive ions switch places AB+CD AD+CB E. combustion: carbon and hydrogen react on the presence of oxygen, produc
