Acar traveling with constant speed travels 150km in 7200 s. what is the speed of the car

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

State one important difference between a physical change and a chemical change?

If e is the symbol for an element, which two of the following symbols represent isotopes of the same element? 1. e2. e3. ea.1 and 2c.1 and 4b.3 and 4d.2 and 3