A 0.622 g sample of sodium carbonate was treated with sulfuric acid (H2SO4) instead of hydrochloric acid. Calculate the mass of sodium sulfate (Na2SO4) expected.

△JKL ≅ △XYZ by HL congruency for right triangles

Step-by-step explanation:

If only given two sides and an uncontained angle, the triangles may not necessarily be congruent. However, since the given angle is a right angle, they are congruent.

When given that the hypotenuse and any "leg" of the right triangles are equal, the triangles are congruent.

Since one angle is 90°, the other two angles must be acute. This is unlike the ambiguous case when given an uncontained acute angle, where two possible triangles can be made by making another angle obtuse.

Imagine an isosceles triangle cut in half at the altitude, creating two right triangles (JKL and XYZ). They have the same angle measures. Each with a right angle, the angle that had an equal measure in the isosceles, and the unequal angle bisected. For the triangles' sides, the isosceles base was bisected by the altitude, and they have the same altitude.