The hypothesis is that salt water freezes faster than fresh water.
The dependent variable is time taken for ice to appear.
The independent variable is presence or absence of salt
The constants are the amount of water in each tray, freezing conditions and length of time of exposure to freezing condition.
The control group is the tray to which salt was not added
The experimental group is the tray to which salt was added
The presence of solutes in a solution causes the freezing point depression.
A solution is made up of a solute and a solvent. In the presence of a solute, the freezing point of a pure solvent is decreased. This is because freezing point is a colligative property.
Colligative properties depend on the amount of solute present.
Hence, the pure water freezes faster (ice begin to appear earlier) than the salt water.
The hypothesis put forward in this experiment was found to be invalid by the experiment.
For more about colligative properties, see
brainly.com/question/10323760
Answer:
there are 20 oxygen atoms in 4.00 moles of Dinitrogen pentoxide
Explanation:
there are 2 atoms in an oxygen molecule , so each oxygen molecules has at least 2. Dinitrogen pentoxide is N2O5, which has 7 atoms, 2 nitrogen and 5 oxygen. 1 molecule of N2O5 has 5 oxygen atoms, so 4 of then would be 20
A decomposition reaction should look like
A ------> B +C+...
It has to have only one reactant and several products.
2 NO2 ⟶ 2 O2 + N2
