A train travels 99 km in two hours and then 72 km in two hours what is it's average speed

Which of the following groups of chemical elements would you expect to be most alike in their physical and chemical properties?

A sample of ideal gas is in a sealed container. The pressure of the gas is 565 torr torr, and the temperature is 3 ∘C∘C.

The volume of a gas is 4.0 L, the pressure is 1 atm, and the temperature is 200 K. A chemist changes one factor while keeping another constant so that the new volume is 5.0 L. Which of the following could be the new conditions? A.

An atom with 39 protons and a mass number of 89 what is the number of neutrons

What occurs when sediment gets deposited as the energy of the water decreases?

Fruit flies can either have a brown body or a black body. The allele for a brown body (B) is dominant to the allele for a black body (b). A brown fruit fly was crossed with a black fruit fly as shown below.

A light-year measures the distance a light beam can travel in one year. One light-year is equal to 9 500 000 000 000 kilometers.

The first ionization energy, e, of a potassium atom is 0.696 aj. what is the wavelength of light, in nm, that is just sufficient to ionize a potassium atom? values for constants can be found here.

A gene is a to a chromosome as (A) a pea is to a pod (B) a front to a back (C) a bike is to a car (D) a building is to a window

How are you enjoying this weather? (i need good reasons}