Answer:
No, it's a physical reaction.
Explanation:
A chemical change produces new chemical compounds, but combining water and powder is just mixing the powder with the water. It's not a new compound.
I don't know how to really explain, sorry :)
Answer:
The half life is 
Explanation:
The half life of a first order reaction is mathematically represented as
Substituting
for the rate constant

Answer:
They usually lose electrons to form ions with 2 positive charges
Explanation:
Answer:
Fluid power systems perform work by a pressurized fluid bearing directly on a piston in a cylinder or in a fluid motor. A fluid cylinder produces a force resulting in linear motion, whereas a fluid motor produces torque resulting in rotary motion. Within a fluid power system, cylinders and motors (also called actuators) do the desired work. Control components such as valves regulate the system.