PLEASE HELP Ariana and Alissa performed the synthesis of Ag2SO4. They measured a known mass of AgNO3, dissolved the salt in water and added this solution to an excess of aqueous K2SO4. They filtered the precipitate of silver sulfate, rinsed it with distilled water, and let it dry overnight. Next day, the mass of silver sulfate was measured. The collected results are shown in the Data Table below.
2 AgNO3(aq) + K2SO4(aq) à Ag2SO4(s) + 2 NaNO3(aq)

After doing the calculations of the theoretical yield and the percent yield, Ariana reports the % yield to be 91.0%, while Alissa claims it is 83.5%. Explain, by doing the corresponding calculations, which of the two students is correct.
Mass of watch glass
2.589 g

Mass of watch glass + AgNO3

5.739 g

Mass of beaker
15.486 g

Mass of beaker + Ag2SO4

18.116 g

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol

some sources quote the lethal dose, for an average 170lbs opiate-naive individual is between 75 and 375 mg