[olivetree]

i need help on my sig figs can anyone give some advice on my math?

1. Volume of the acid (final - Initial)
29.10 - 20.30= 8.80 mL

2. Volume of the base (final - initial)
16.80 - 5.20= 11.60 ml

3. Concentration of acid ( MA x #H⁺ x VA = MB x #H⁺ x VB)
X × 1 × 8.80= .50 × 1 × 11.60
8.80x=5.8
8.80 8.80
x=0.66M
Part 2
1. Volume of the acid (final - Initial)
35.30 - 20.10= 15.20 mL

2. Volume of the base (Final - Initial)
41.40- 16.80= 24.60 mL

3. Concentration of the acid ( MA x #H⁺ x VA = MB x #H⁺ x VB)
X × 1 × 15.20= .50 × 1 × 24.60
15.20x=12
15.20 15.20
x=0.81 M

4. Moles of acetic acid ( M=moles / liters)
.81= x ÷ .015
x=0.01 mols

5. Grams of acetic acid ( # moles= grams / gfm)
.01= x ÷ 60
x= .7g

6. % acetic acid (% acetic acid= Grams acetic acid × 100)
Grams vinegar
x= .7 × 100
15.20
x=4% acetic acid

7. % error(true value 5.0%)
% error= Measured value - accepted value × 100
accepted value
x= .04 - .05
.05
x= I -0.05× 100 I
x= I -5 I
x= 5% error

[Dan]

4. Moles of acetic acid ( M=moles / liters)
.81= x ÷ .015
x=0.01 mols

1. Don't round until the end - you have rounded 0.01520 L to 0.15 before doing the calculation
2. The least accurate number is concentration 0.81 M. This is 2sf, so you should give your answer to 2sf. Your answer is currently to 1sf (and 2dp).

http://en.wikipedia.org/wiki/Significance_arithmetic

[Borek]

Also: all your volumes are given as xx.x0 - is the last digit (zero) really significant?