Calculate the weight in grams of the primary standard solid oxalic acid needed to prepare 250 ml of a 0.200 n solution to be used in this laboratory exercise.

2.25 g.

Explanation:

N = (mass / equivalent mass) of the solute x (1000 / V of the solution)

The solute is oxalic acid.

N is the normality of the solution (N = 0.2 N),

mass of the solute (oxalic acid) (??? needed to be calculated),

equivalent mass of the oxalic acid = molar mass / n (the no. of reproducible H) = (90.03 g/mol) / (2) = 45.015.

V is the volume of the solution (V = 250 ml).

∴ The mass of the oxalic acid in g = (N x equivalent mass x V) / 1000 = (0.2 N) (45.015) (250.0 ml) / 1000 = 2.25 g.

Very important note:

If the solute source is oxalic acid dihydrate:

The molar mass = 126.07 g/mol.

The equivalent mass = 63.035 g.equ./mol.

∴ The mass of the oxalic acid in g = (N x equivalent mass x V) / 1000 = (0.2 N) (63.035) (250.0 ml) / 1000 = 3.15 g.

away from the curb

explanation:

the wheels would then hit the curb if it started to rolling, decreasing the chance of an accident.

the transfer of heat by electromagnetic radiation is called thermal radiation . it is usually carried out by electromagnetic waves in an energy range just below the visible spectrum, which is the infrared range.

so the answer would be radiation.

: )