Chemistry uncertainty and sig figs

Question

can anyone help me with this

1) which number if the measure value is 8.4I26, which of the numbers has uncertainty

2) if the scale division 0.1 unit, and the measurement values at 3.2 units, how do u record to show where the uncertainty is located

4) if the smallest division on the scale is 0.1mL. and a flask reading was on the 10mL mark, how should u record it

a) 10ml

b) 10.00 ml

c)10.0ml

d)10.001 mL

Answer 1

1) The last significant digit is uncertain. That is what it is indicating.

2) Nonzero digits are always significant. 3.2 units is rounded to the nearest .1 units.

4) Measuring to the nearest .1 ml you must write the measurement of 10 as 10.0 ml to tell people that you measured 10.0 rather than 10.1 or 9.9. If you write 10 ml, that actually implies one sig fig, so it indicates 10, not 20 or 0 ml.