Which phrase describes a compound that consist of two elements

Scientists often have to deal with numbers that are either very large or very small. for example, the radius of the sun is approximately 696,000 kilometers, while bacterial cells are as small as 1.9 × 10-4 millimeters. express each number in an alternate form.

Which of the following describes the entropy change as a solution is made from a liquid and solid

0.070g of hydride of carbon occupies 56cm^3 at s. t.p when vaporized and contained 14.29% by mass of hydrogen. what is the formula for the hydrocarbon