A Change in matter that can be seen through direct observation are called?

How many calories are in a peanut butter and jelly sandwich

One mole of any element contains the

Enter your answer in the provided box. A mixture of helium and neon gases is collected over water at 28°C and 791 mmHg. If the partial pressure of helium is 381 mmHg, what is the partial pressure of neon? (Vapor pressure of water at 28°C is 28.

A scientist has two solutions, which she has labeled Solution A and Solution B. Each contains salt. She knows that Solution A is salt and Solution B is salt. She wants to obtain ounces of a mixture that is salt.

A sample of nitrosyl bromide (nobr) decomposes according to the equation 2nobr (g) ⇌2no (g) + br2 (g) an equilibrium mixture in a 5.00-l vessel at 100 ∘c contains 3.26 g of nobr, 3.06 g of no, and 8.15 g of br2. part a calculate kc.

Which of the following is true concerning the noble gases? A. Their highest occupied s and p sublevels are filled. B. They belong to Group 8A. C. They are sometimes referred to as the inert gases. D. all of the above

Which of the following is responsible for passing albinism from a parent organism to its offspring?

Rubidium has two naturally occurring isotopes, rubidium - 85 (atomic mass = 84.9118 amu; abundance = 72.15%) and rubidium - 87 (atomic mass = 86.9092; abundance = 27.85%). Calculate the atomic weight of rubidium

You are asked to analyze an aqueous solution (X) and determine what's in it. You pour some of your sample X into a test tube and add a few drops of an acid. No observable reaction occurs.

Which of the following items represents a chemical change? burning melting evaporation freezing