Which one of the following is a double-displacement reaction?
~there can be more then one answer~

a. 2h2 (g) + o2 (g) → 2h2o (g)
b. 2h2o (l) → 2h2 (g) + o2 (g)
c. naoh (aq) + hcl (aq) → nacl (aq) + hoh (l)
d. cu (s) + 2agno3 (aq) → cu(no3)2 (aq) + 2ag (s)

Argon is adiabatically compressed from an initial volume of 16 liters to a final volume of 2 liters. by what factor do the following quantities change? do they increase or decrease? (a) the rms speed (b) the thermal energy of the gas (c) the molar specific heat cv (d) the pressure

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?

How are the crust and the inner core alike? a) they are both solid. b) they both have the same temperature. c) they are both under the same pressure. d) they are both very close to the center of the earth.