Which of the following is a pure substance?

a. soda

b. gun powder

c. sugar water

d. steam

Explain how it is possible for a compound to have both ionic and covalent bonds

If all of the forces acting on a car are balanced, then

When communicating with Apollo astronauts, there is approximately a 1.3 second delay in one-way communication. This is because A) space is a vacuum. B) the moon has virtually no atmosphere. C) radio waves travel at a speed of 186,000 miles/s.

What is an inference?

How do the reaction rates change as the system approaches equilibrium?

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?