In 1982, the composition of a penny changed from 95% copper and 5% zinc to 95% zinc and 5% copper. Compare the relative densities of a penny that was made in 1981 to a penny made in 1995.

Suppose a lab group reports a ppercent yield of sand of 105. is it really possible to collect more sand than was originally represented? what is the possible explanation for the extra product?

Which item is most likely part of the safety contract

What does a complete balanced chemical equation include? a. exothermic coefficients b. endothermic coefficients c. valence electrons d. molar coefficients