It's a test
2naoh + h2so4 → na2so4 + h2o
the equation is [balanced/unbalanced], because the number of hydrogen atoms and [oxygen/sodium] atoms is [equal/not equal] in the reactants and in the products.

Asolid cylinder and a cylindrical shell have the same mass, same radius, and turn on frictionless, horizontal axles. the cylindrical shell has light-weight spokes connecting the shell to the axle. a rope is wrapped around each cylinder and tied to blocks of equal masses that are held the same height above the ground. both blocks are released simultaneously. the ropes do not slip. which block hits the ground first? or is it a tie?

Heterogeneous mixture with larger particles that never settle is

Ascientist wants to test ways to reduce pollution in lake . what is the bestway of doing this