Jack wants to find out which laundry detergent cleans the best ( gain, tide, or purex). so, he takes a cotton sheet and cuts it up into equal squares. he stains four squares with chocolate, and four with grape juice. he washes one of each of the squares in each of the 3 detergents. one from each set of squares is washed in water alone. for each wash load, he used: the same amount of water, the same amount of detergent, and the same temperature of water. find the independent variable, dependent variable, control (constants) and write a hypothesis for the outcome.

A scientific experiment should contain three variables:  

1 Dependent variable: the variable which has to be studied in the experiment.

2 Independent variable: the variable which can be manipulated or gets changed in the experiment.

3. Control variable: the variable which is kept constant or the same throughout the experiment.

In the given question.

1. Independent variable is the type of laundry reagent.

2. Dependent variable- the clean cloth after washing.

3. Control variable- the amount of water, the temperature of the water and the amount of detergent.

chemical properties of thing

  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