What is it called when matter changes directly from a solid to a gas?

When sea ice forms, the surface water beneath the ice becomes less dense?

What is a good hypothes is for this problem statement:Problem statement: Does changing the amount of water affect the time it takes water to boil?

A squirrel has a mass of 0.5 kg. What is it's weight?

Identify the elements in the compound NaCl.

What is the part of the steam engine that does the work? A. The flywheel B. The cylinder C. The piston D. The turbine

An LC circuit has a 6.00 mH inductor. The current has its maximum value of 0.570 A at t = 0s. A short time later the capacitor reaches its maximum potential difference of 66.0 V. What is the value of the capacitance?

The first law of thermodynamics states that ΔE = Q - W. Is this also a statement of the principle of conservation of energy? Yes, the heat added and the change in internal energy of the gas equal the work done by the piston.

How can we calculate the density of a sustance that has irregular volume

A two stage rocket leaves its launch pad moving vertically with an average acceleration of 4 m/s2. at 10 s after launch the first stage of the rocket (now without fuel) is released.

A liquid filled sealed system has cylinders with movable pistons on each end. The face of one piston has an area of 5 cm². The other piston has an area of 500 cm² and is supporting a weight of 2 kN on it.