Solid samples of the element phosphorus can be white, black, or red in color. The variations in color are due to different

(1) atomic masses

(2) molecular structures

(3) ionization energies

(4) nuclear charges

The vapor pressure of ethanol at 25°C is 7.828 kPa. Calculate the vapor pressure in atm.

The molar mass of oxygen is 16.00 g/mol. how many moles of oxygen are in copper oxide?

How many moles of lead (II) hydroxide (solid) can be formed when 0.0225L of 0.135M Pb (NO3) 2 solution reacts with excess sodium hydroxide?

How many molecules of H2O are equivalent to 97.2g H2O

20950 joules of heat are added to a container with 400 g of water. how much does the temperature change? Show work and formula.

What are elements and how do they differ?

Write the structire of the salt that forms when diethylamine is mixed with hydrochloric acis

The heat of combustion of propane, C3H8, is 2220 kJ/mol. The specific heat of copper is 0.385 J/g°C. How many grams of propane must be burned to raise the temperature of a 10.0 kg block of copper from 25.0°C to 65.

Which is an example of Temporal Isolation? A. Flowers that bloom in different months. B. Birds that have different mating calls C. Fruits flies that mate in different locations. D. Squirrels that have different fur colors

A chemical reaction can start when enough activation energy is added to the reactants. Do you think the activation energy for chemical reactions in living things is high or low / Explain your answer