For each balance in Model 1, circle the phrase below that best describes how closely the mass can be determined with that balance.
Econo-Balance rounded to the rounded to the rounded to the rounded to the
nearest 100 g nearest 10 g nearest 1 g nearest 0.1 g
Good Balance rounded to the rounded to the rounded to the rounded to the
nearest 100 g nearest 10 g nearest lg nearest 0.1 g
Balance Pro rounded to the rounded to the rounded to the rounded to the
nearest 100 g nearest 10 g nearest lg nearest 0.1 g
Exacto-Balance rounded to the rounded to the rounded to the rounded to the
nearest 100 g nearest 10 g nearest lg nearest 0.1 g

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂

1) estimating temperature to the nearest tenth of a degree

2) estimating the mass of the sample to the nearest tenth of a gram

4) the position of the cups of sand and water under the heat lamp