How many hydrogen atoms are needed to form five water molecules

14.0L of nitrogen gas at STP to moles?

In the food chain, the frog is classified as a

A new potential heart medicine, code-named X-281, is being tested by a pharmaceutical company, Pharma-pill.

Describe what happens to the particles in a chocolate bar as it melts. a. As the chocolate bar changes from a solid to a liquid a chemical change happens. b. As the chocolate bar changes from a solid to a liquid the particles slow down. c.

Which radioactive isotope is commonly used to date wooden artifacts?

O2 (g) → O2 (l) Predict whether the reaction above would have an increase or a decrease in entropy.

The periodic law states that the physical and chemical properties tend to repeat periodically when elements are arranged according to what trend

In which of the following situations does water undergo a change in physical properties? a. The bathroom fills with steam when you take a hot shower. b. The neighbor's pond freezes over in winter. c. Water is broken down to yield H2 and O2. d. a.

Which statement best describes the ideas of two scientists who studied properties of light? Newton and Maxwell had similar ideas about light being made of particles.

As transformações estão presente em nosso cotidiano, elas nunca param de acontecer, na sua maioria invisível a olho nu. Quais critérios é preciso observar para identificar se ocorreu transformação?