When does a cold front develop?

when a cold air mass invades a warm air mass

when two masses of warm air meet

when two masses of cold air meet

when a warm air mass invades a cold air mass

What do chemical compound and mixture have in common

The density of ethanol is 0.789 g/ml. what is the density in units of kg/m3?

Why is burning is not a recommended method of disposing plastics

An atom of potassium with a mass number of 40 is known as K-40. Use the periodic table to determine how many neutrons are present in an atom of K-40. Type the correct answer in the box. Use numerals instead of words. One atom of K-40 has neutrons.

How many electrons does nitrogen have in its outer energy level?

Mass box A = 10 grams; Mass box B = 5 grams; Mass box C-made of one A and one B How much A and B would be needed to produce 30 grams of C? g of A; g of B.

How many moles of tin atoms are in a pure tin cup with a mass of 37.6 g?

Which best explains how Dmitri Mendeleev organized elements in his periodic table? O A. Elements were ordered based on their discovery date. O B. Elements were ordered based on their economic value. O C.

The rocks and minerals of the Earth consist of compounds.

Do the number of protons in an atom of an element always equals its atomic weight.