What must be true for a spontaneous reaction in an electrochemical cell? The overall cell potential must be positive.
The overall cell potential must be negative.
The cathode's standard reduction potential must be positive.
The cathode's standard reduction potential must be negative.

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils