In a chemical reaction, atoms are created or destroyed. true or false user: heat, gas production, and color change can all be evidence of chemical change. true or false

What is a 'phase transition'? Using water as an example explain the major differences between the three physical states (phases) of water.

A sample that weighs 107.75 g is a mixture of 30% helium atoms and 70% krypton atoms. How many particles are present in the sample?

What volume of a 0.303 m hydroiodic acid solution is required to neutralize 20.5 ml of a 0.167 m calcium hydroxide solution?

A new and effective antibiotic becomes widely used for a particular species of bacteria. After some time, an antibiotic-resistant strain of the bacteria becomes prevalent. Which mechanism explains this phenomenon?

When conducting this experiment some procedures call for heating the substance several times and recording the mass after each heating continuing until the mass values are constant. explain the purpose and how it might reduce error.

Is made by the ears to prevent pathogens from entering the body A) wax. B) bile. C) mucus. D) pus

Pieces of sediment settle out of water and wind during

Is Vitamin E an element?

Which gas sample would likely not act like an ideal gas? Choose one of the following, 1. A sample of oxgen gas at low pressure 2. A sample of oxygen gas at high temperature 3. A sample of argon gas at high pressure 4.

Ryan is a 13-year-old male who has just entered puberty. Which change can Ryan expect during this stage of his life? a thinning of body hair an increase in high-risk behaviors a more restful sleep pattern a decrease in vocal ability