Which substance can not be broken down by chemical means?

(1) ammonia (3) methane

(2) antimony (4) water

Calculate the mole fraction of phosphoric acid (H3PO4) in a 25.4% (by mass) aqueous solution.

List four observation that suggest a chemical change is occuring

Which one of the following is not a true statement about water purification. Group of answer choices a. water can be desalinated by reverse osmosis b. water can be desalinated by distillation c. water can be purified by chlorination d.

Why is the amount of usable energy lower for anaerobic respiration than for aerobic respiration

Why would an eclipse not occur every time the moon and the earth are in these positions?

Which of these is a mixture? salad sugar water potassium

Explain the steps to determine presence of pb2 + ions

A 2-kg box is pushed from rest to a speed of 29.7 m/s in 21 seconds. What is the power require to accelerate the box.

Gamma rays are produced by applying

Which of the following is an example of a chemical change? A bike rusting Mixing salt and pepper A brick breaking Gold melting