Which of the following always occurs in a

chemical reaction?

A) a gas is given off.

B) a solid is produced,

C) a new substance is produced.

D) a colour change takes place.

Serotonin is a compound that conducts nerve impulses in the brain. it contains 68.2 mass percent c, 6.86 mass percent h, 15.9 mass percent n, and 9.08 mass percent o. its molar mass is 176 g/mol. part a determine its molecular formula.

State the periodic law, and explain its relation to electron configuration. (Use Na and K in your explanation.)

Each family in the periodic table has its own characteristic properties based on the number of what

How many valence electron do xenon have

Based on the Lewis/electron dot representation of the two atoms, predict the ratio of metal cationic (+) atom to nonmetal anionic (-) atom in the compound. . Ca: A. 1:1 B. 1:2 C. 2:1 D. 3:1

10) A screwdriver has the density of 5.5 grams per cubic centimeter. It also has the mass of 2.3 grams. What is the screwdriver's volume?

A chemist weighed out 20.7 g of sodium. Calculate the number of moles of sodium she weighed out

If 1.00 mol of argon is placed in a 0.500-L container at 20.0 ∘C, what is the difference between the ideal pressure (as predicted by the ideal gas law) and the real pressure (as predicted by the van der Waals equation) ? For argon, a=1.

Part 2: Finding Speed and Height Using Energy Directions: Use the KE and GPE equations to solve for speed or height depending on the situation. 1. A 1,000-kg car has 50,000 joules of kinetic energy. What is its speed? 2.

Why is conductivity be the best test to find a metal, non-metal or metalloid?