look at the two question marks between zinc (zn) and arsenic (as). at the time, no elements were known with atomic weights between 65.2 and 75. but mendeleev predicted that two elements must exist with atomic weights in this range.
what led mendeleev to predict that two undiscovered elements existed in that range?

Ascientist measures the speed of sound in a monatomic gas to be 449 m/s at 20∘c. what is the molar mass of this gas?

Acm ruler with main graduations from 1 to 10 from left to right there are 10 secondary graduations between each of the main graduations there is a line that begins. at the left end of the ruler 10 secondary graduations to the left of the “1 main graduation the right end of the line ends on the eighth secondary graduation to the right of 3 how long is the line

Asample of sea water contains 6.28g of sodium chloride per litre of solution. how many milligrams of sodium chloride would be contained in 15.0ml of this solution?