Recent content by fghtffyrdmns

Homework Statement A circular disk of radius r is used in an evaporator and is rotated in a vertical plane. If it is to be partially submerged in the liquids as to maximize the exposed wetted area of the disk, show that the center of the disk should be positioned at a height r/ \sqrt{1+\pi^2}...

v1 = c2v2/c1 v1 = (1.25 L)(2.75 mol/L)/(15.8585 mol/L) = 0.217 L.

If you multiply the H3PO4 by 3, you would have a ratio of 1:1 with NaOH:H3PO4. So you could write c1v1=3c2v2?

ahhh so could I write sinA = \theta?

Homework Statement Determine sin(arctan(3)) The Attempt at a Solution I do not know how to start this. No special triangles : (.

sin(pi)= 0 cos (pi) = -1 tan (pi) =0. Is that all?

Homework Statement Find the trigonometric ratios sin\theta, cos\theta, tan\theta for the angle \theta = 14\pi. If a ratio does not exist or is undefined, write "DNE". The Attempt at a Solution I know that the other equivalent angle for 15pi is just pi. But I do not know how to write the...

(0.85)(1.83 g/mL)(1000 mL/L)(1 mol/98.086 g) This gives you the concentration Then you can simply find the volume with c1v1=c2v2.

The H3PO4. This way you would have a 1:1 ration, correct?

Yes, I learned the hard way. I wrote the balanced equation of H3PO4 + 3 NaOH -> 3 H2O + Na3PO4 3CnaohVnaoh = Ch3po4Vh3po4 Is this wrong?

That's what's confusing me. If I do this, I get the wrong answer.

Homework Statement An aqueous stock solution is 85.0% H2SO4 by mass and its density is 1.83 g/mL. What volume of this solution is required to make 1.25 L of 2.75 mol/L H2SO4(aq)? Give your answer in millilitres, accurate to three significant figures. Homework Equations c1v1=c2v2 The...

But I'm trying to find the volume of NaOH. There's 3:1 ratio.

so, 3c1v1 = c2v2 then v1 = c2v2/3c1 ? This would give me 6.80x10^-2 L.

Elaborate.