What is the change in enthalpy for a reaction if the reactants have 270 kJ of energy and the products have 150 kJ of energy?*
120 kJ
-120 kJ
420 kJ
-420 kJ

How do forces between particles in gases compare to forces in the other states of matter? o a. the forces in gases are stronger than forces in solids but weaker than forces in liquids. o b. the forces in gases are weaker than forces in solids but stronger than forces in liquids. o c. the forces in gases are weaker than forces in solids and liquids. o d. the forces in gases are stronger than forces in solids and liquids. submit

Consider three unlabeled bottles, each contain small pieces of one of the following metals. - magnesium - sodium - silver the following reagents are used for identifying the metals. - pure water - a solution of 1.0 molar hcl - a solution of concentrated hno3 (a) which metal can be easily identified because it is much softer than the other two? describe a chemical test that distinguishes this metal from the other two, using only one of the reagents above. write a balanced chemical equation for the reaction that occurs. (b) one of the other two metals reacts readily with the hcl solution. identify the metal and write the balanced chemical equation for the reaction that occurs when this metal is added to the hcl solution. use the table of standard reduction potentials (attached) to account for the fact that this metal reacts with hcl while the other does not. (c) the one remaining metal reacts with the concentrated hno3 solution. write a balanced chemical equation for the reaction that occurs. (d) the solution obtained in (c) is diluted and a few drops of 1 m hcl is added. describe what would be observed. write a balanced chemical equation for the reaction that occurs.

Which of the following signs of a chemical reaction are observed in the reaction of potassium with water? precipitate formed temperature change smell produced gas produced color change