Questions

The law of conservation of mass states that in any closed system the mass of the system is neither created nor destroyed over time i.e, the mass cannot be changed overtime.

Hence, the given statement is true.

Sound waves cannot be transmitted through vacuum. 

The oxygenated blood  flows through pulmonary veins then leaves the lungs, which return it to the left heart, completing the pulmonary cycle.

Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na+ and hydroxide anions OH−.

Properties:

1. It is highly soluble in water, and readily absorbs moisture and carbon dioxide from the air.

2. NaOH is insoluble in ether and other non-polar solvents.

3. It is an odorless compound.

Uses:

Sodium hydroxide is used in many industries: in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents, and as a drain cleaner.

The kilowatt hour (kW⋅h) is a composite unit of energy equivalent to one kilowatt (1 kW) of power sustained for one hour.

One watt is equal to 1 J/s. One kilowatt hour is 3.6 megajoules.

Proxima Centauri is the nearest star to the Earth.