By titration it is found that 49.3 ml of 0.151 m naoh(aq) is needed to neutralize 25.0 ml of hcl(aq). calculate the concentration of the hcl solution.

0.298 M The balanced equation for the reaction is HCl + NaOH = H2O + NaCl So for every mole of NaOH used, one mole of HCl is neutralized. So let's determine how many moles of NaOH we used. That will simply be the volume (in liters) of solution multiplied by the molarity. So 0.0493 L * 0.151 mol/L = 0.0074443 mol Because of that 1:1 ratio, we now know that 0.0074443 moles of HCl was in the sample. Since molarity is moles per liter, a little division will give us the molarity of the HCl solution. So 0.0074443 mol / 0.025 L = 0.297772 mol/M = 0.297772 M Rounding to 3 significant figures gives 0.298 M.

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.