Is erasing a pencil mark a chemical or physical change?

1. The combustion of ethene, C2H4, is an exothermic reaction. Use the information below to determine the amount of energy given off when 2.3 moles of ethene is combusted. C2H4 + 3 02 02 CO2 + H2O AH = - 1390 kJ

Acetylcholine causes an end-plate potential by triggering the

What happen to the average kinetic energy of the remaining molecules as gaseous molecules evaporate from a liquid

What happens when you send the light through the diffraction lens?

How is the atomic mass of an element calculated? A. by determining the number of electrons in the outer orbital B. by determining the number of protons in the nucleus C.

What substances have an arrhenius base?

Which of the following correctly states the relationship between temperature and the solubility of a substance in water? Group of answer choices The solubility of a substance in water increases as the temperature rises, especially for gases.

How many moles of water are made from complete reaction of 1.4 moles of hydrogen gas? Given the reaction: 2H2 + O2 → 2H2O

A scientific law is 1. A university accepted conclusion based on testing 2. Always changing a new evidence is presented 3. Based on new evolving theories 4. Often debated in the scientific community 5. One step toward forming a theory

12 Two molecules of HBr collide and then form H2 and Br2. During the collision, the bonds in the HBr molecules are