Los isotopos oxigeno 16 oxigeno 17 yoxigeno 18 se diferencian en

Which statement describes evidence of a chemical reaction? a) ice melting eliminate b) water boiling c) lighting a match d) grape juice freezing

Which of the following statements is false regarding aromaticity? a. the compound must be cyclic b. the compound must be fully conjugated c. the compound must be planar d.the number of electrons in the pi system must satisfy the hückel 4n+2 rule e. the compound must have a neutral charge

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.