A sample of hydrated calcium sulphate, CaSO4.xH2O, has a relative formula mass of 172. What is the value of x?

Which of the following elements would you expect to have the lowest ionization energy value? fluorine, lithium, neon, nitrogen

Use the drop-down menus to answer each question. which runner finished the 100 m race in the least amount of time? which runner stopped running for a few seconds during the race? at what distance did anastasia overtake chloe in the race?

1) which of the following is the best example of a physical change? a) sugar dissolving in tea b) firefly glowing 2) in the combustion of ethane, what is/are the reactants? c2h6 + o2 ==> co2 + h2o a) c2h6 and o2 b) co2 and c2h6