Answer: TWO.
At least two groups: treatment group and control group.
The treatment group is that is exposed to the different levels of the independent variable ( a medication for example), while the control group is not treated, so the researchers can compare the effect of the medication.
Answer:
They are similar in sense that both cannot dissolve any more solid unless heat or other factors are added. For eg if a solution is saturated it can no longer dissolve the given substance. But if the solution is heated, the solid will dissolved this is now said to be supersaturated.
Explanation:
Answer: Option (C) is the correct answer.
Explanation:
In a substance, the total energy of its molecular motion is known as heat. Whereas when we measure the average energy of molecular motion of a substance then it is known as temperature.
So, any increase or decrease in temperature will lead to change in heat of a substance.
When one mole of a substance is burned then the amount of energy released in the form of heat is known as heat of combustion.
Relation between heat and temperature is as follows.
q = 
Thus, we can conclude that to measure the enthalpy of combustion it cannot be measured, only calculated using the equation; q = 
.
Answer:
Volume of ammonia produced = 398.7 dm³
Explanation:
Given data:
Volume of N₂ = 200 dm³
Pressure and temperature = standard
Volume of ammonia produced = ?
Solution:
Chemical equation:
N₂ + 3H₂ → 2NH₃
Number of moles of N₂:
PV = nRT
1 atm× 200 L = n× 0.0821 atm.L/mol.K × 273 K
n = 200 atm.L /22.41 atm.L/mol
n = 8.9 mol
Now we will compare the moles of ammonia and nitrogen.
N₂ : NH₃
1 : 2
8.9 : 2/1×8.9 = 17.8 mol
Volume of ammonia:
1 mole of any gas occupy 22.4 dm³ volume
17.8 mol ×22.4 dm³/1 mol = 398.7 dm³
Answer: Ions are formed by the addition of electrons to, or the removal of electrons from, neutral atoms or molecules or other ions; by combination of ions with other particles; or by rupture of a covalent bond between two atoms in such a way that both of the electrons of the bond are left in association with one of the ...
