An atom of potassium has 19 protons and 20 neutrons. what is its mass number?

A bird is able to easily soar when it flies over a thermal. A thermal is a current of warm air that is heated by the ground and rises up into the sky, taking the bird with it. What is this an example of? A. Conduction B. Radiation C. Contusion D.

What type of calorimeter would be best to use if you wanted to measure the heat that is released when gasoline is burned? Constant Density Calorimeter Constant Temperature Calorimeter Constant Volume Calorimeter Constant Pressure Calorimeter

Ethyl chloride vapor decomposes by the first-order reaction c2h5cl → c2h4 hcl the activation energy is 249 kj/mol and the frequency factor is 1.6 * 1014 s-1.

The model below shows an atom of an element. 9 light grey and 8 dark grey balls sit at the center with 2 concentric black rings around them. The inner ring has 2 medium grey balls on it, and the outer ring has 6 medium grey balls on it.

Which is a physical change? A Strawberries left out to mold B Strawberries liquified in a blender C Strawberries cooked into jelly

Identify the spectator ions in the following complete ionic equation. 2k (aq) s2 - (aq) pb2 (aq) 2no-3 (aq) →pbs (s) 2k (aq) 2no-3 (aq) express your answers as ions separated by a comma.

4. A bird left its post and flew in a triangular path. It flew 21 yards south, 72 yards east and 75 yards diagonally to end back at the post. Is it a right triangle?

Condension occurs in the inside of your windows in Winters, why?

How can you use Hess's law to determine a reaction's enthalpy?

7. How much energy in KJ is released when 15.0 g of steam at 100.0 degrees Celsius is condensed and then frozen to ice at 0.0 degrees Celsius?