At some point during construction, the International Space Station had a mass of 235,565 kg. When it orbited the Earth at an altitude of 400,000 m,
what was the approximate gravitational force on the Station due to Earth's
gravity? (Recall that Earth has a radius of 6.37 x 106 m, it has a mass of 5.97
x 1024 kg, and G = 6.67 * 10-11 N·m²/kg?.)

Achemistry student weighs out 0.306 g of citric acid (h3c6h5o7), a triprotic acid, into a 250 ml volumetric flask and dilutes to the mark with distilled water. he plans to titrate the acid with 0.1000 m naoh solution. calculate the volume of naoh solution the student will need to add to reach the final equivalence point. be sure your answer has the correct number of significant digits.