What is the iodide ion concentration in a solution if the addition of an excess of 0.100 m pb(no3)2 to 42.9 ml of the solution produces 861.8 mg of pbi2?

Astudent pushes on a 20.0 kg box with a force of 50 n at an angle of 30° below the horizontal. the box accelerates at a rate of 0.5 m/s2 across a horizontal floor. what is the value of the normal force on the box? 200 n 243 n 156 n 225 n