Answer: A
Explanation: mechanical weathering —Water gets into the cracks, freezes and expands making the cracks bigger. When there is thawing, the ice melts into water and more water gets into the rock. Freezing can happen again and the cracks get bigger.
First of all, you need to convert mL to L; 120mL = 0.12L, 300mL = 0.3L.
n (moles of carbonic acid) = C (concentration) x V (volume)
n = 0.15M (0.15 mol L-1) x 0.12L
n = 0.018 mol
C (conc. of NaOH) = 0.018 mol x 2 moles (because there’s 2x NaOH) = 0.036 mol
C = n / V
C = 0.036 mol / 0.3 L
C = 0.12 mol L-1
John Dalton in d year 1808 proposed d atomic theory..
1.All elements are made up of small, indivisble particles called atoms.
2.Atoms can neither be created nor destroyed.
3.Atoms of d same element are alike in every aspect, &differ from atoms of all other elements.
4. When atoms combine with other atoms, they do so in simple ratios.
Answer: (although the question does not sate whether if you separate them physically or through energy. so i did both)
1. can be separated (When high-energy ultraviolet rays strike ordinary oxygen molecules (O2), they split the molecule into two single oxygen atoms, known as atomic oxygen)
2. can be separated, but through electrolysis, fiscally moving a crane to generate electricity to separate the molecules
3. Most solid particles, composed of diamagnetic or weak paramagnetic materials, cannot be extracted by a conventional magnetic separator. physically cannot be separated. but through heat yes
4. but there is a catch: doing so requires energy. ... If energy from coal were applied to drive the decomposition reaction, more CO2 would be released than consumed, because no process is perfectly efficient. so it cant be separated physically
5. it can be separated but it needs energy physically cannot be separated.
Explanation:
Answer : The value of 
for the reaction is, -135.2 kJ
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The formation of 
will be,
The intermediate balanced chemical reaction will be,
(1) 
(2) 
(3) 
We are dividing the reaction 1, 2 and 3 and reversing reaction 3 and then adding all the equations, we get :
(1) 
(2) 
(3) 
The expression for enthalpy of formation of will be,
Therefore, the value of for the reaction is, -135.2 kJ
