Which of the following involve endothermic reactions? (select all that apply) a. a chemical cold pack b. gasoline in a car engine c. cooking rice d. a candle flame

What does the symbol (–hfus) indicate in a phase change?

What is a number added in front of a formula in order to balance the equation

Imagine if during the cathode ray experiment, the size of the particles of the ray was the same as the size of the atom forming the cathode. which other model or scientific observation would have also been supported? 1. this would support dalton's postulates that proposed the atoms are indivisible because no small particles are involved. 2. this would support bohr's prediction about electrons moving in orbits having specific energy. 3. this would support bohr's prediction about electrons being randomly scattered around the nucleus in the atom. 4. this would support dalton's postulates that proposed that atoms combine in fixed whole number ratios to form compounds.