Which of these is an example of a chemical change?
2 answers:
Answer: Forming oxygen By bubbling flourine through water
Explanation:
Chemical change is the change in which chemical composition of the substance changes by rearrangement of atoms.
Physical change is a change in which only the physical properties such as size, shape etc change and there is no rearrangement of atoms.
1. Dissolving two cups of flour in a liter changes the state and hence is a physical change.
2. Pouring water from a large trough into a beaker is a physical change.
3. Decreasing the motion of water molecules by freezing changes the state and hence is a physical change.
4. Forming oxygen By bubbling flourine through water involve rearrangement of atoms and thus is a chemical change.
You might be interested in
Answer:
23.0733 L
Explanation:
The mass of hydrogen peroxide present in 125 g of 50% of hydrogen peroxide solution:
Mass = 62.5 g
Molar mass of = 34 g/mol
The formula for the calculation of moles is shown below:
Thus, moles are:
Consider the given reaction as:
2 moles of hydrogen peroxide decomposes to give 1 mole of oxygen gas.
Also,
1 mole of hydrogen peroxide decomposes to give 1/2 mole of oxygen gas.
So,
1.8382 moles of hydrogen peroxide decomposes to give
So,
Pressure = 746 / 760 atm = 0.9816 atm
Temperature = 27 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T₁ = (27 + 273.15) K = 300.15 K
Using ideal gas equation as:
PV=nRT
where,
P is the pressure
V is the volume
n is the number of moles
T is the temperature
R is Gas constant having value = 0.0821 L.atm/K.mol
Applying the equation as:
0.9816 atm × V = 0.9191 mol × 0.0821 L.atm/K.mol × 300.15 K
<u>⇒V = 23.0733 L</u>