Which of the following is a chemical change?

breaking a pencil

freezing water

rusting of an iron nail

liquid nitrogen becoming a gas

an element is a mixture of two isotopes. one isotope has an atomic mass of 34.96885 amu and has an abundance of 75.53%. The other isotope has an atomic mass of 36.96590 amu. Calculate the average atomic mass and identify the element?

True or false table salt is an example of a substance

What's the relationship between the hours of daylight and the temperature

What is the molarity of a solution of nitric acid if 0.283 g of barium hydroxide is required to neutralize 20.00 mL of nitric acid?

What characterizes the fields in Bangkok, Thailand?

A sample of methane gas occupies 4.50 gallons at a temperature of 80.0 F. If the pressure is held constant, what will be the volume of the gas at 100. degrees C?

Jack wants to know if it takes longer for warm water to freeze into ice cubes than cold water, so he performed the following experiment. Jack placed 50 mL of water in the refrigerator and allowed it to cool to a temperature of 4°C.

How to calculate average concentration

Suppose that you measure a pen to be 10.5 cm long. Convert this to meters.

How are amounts of hydrogen and oxygen gas made from the electrolytic decomposition of water related to the chemical formula of water?