Answer is: D. It is not sodium bicarbonate.
Balanced chemical reaction of heating sodium bicarbonate: 2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O.
This is chemical change (chemical reaction), because new substances are formed (sodium carbonate, carbon(IV) oxide and water), the atoms are rearranged, so there is no sodium bicarbonate (NaHCO₃) in the test tube.
Answer:
The adjustable legs and the table of sand.
<em>Note:The question is incomplete. The complete question is given below.</em>
Using Models to Answer Questions About Systems
Armando’s class was looking at images of rivers formed by flowing water. Most of the rivers were wide and shallow, but one river was narrow and deep. Armando’s class thinks that this river is narrow and deep because:
- the hill that the water flowed down was very steep, or
- the sand grains that the water flowed through were very small.
Armando designed the model below to try to answer the question: Why is this river so narrow and deep?
Explanation:
The model designed by Armando will be helpful to answer the question because of the following features it possesses:
1. An adjustable leg- since one of the hypotheses put forward by the class to explain why the river was narrow and deep was that the hill that the water flowed down was very steep, the adjustable legs can be lowered or raised in order to make the slope shallower or steeper so that their hypothesis can be tested.
2. A table of sand- the table of sand serves as the streambed. By adjusting the size of the sand grains to be larger or smaller, the students will be able to to test their second hypothesis that the small size sand grains that the water flowed through was the reason for the river to be narrow and deep.
The results of their experiments will enable them to come to a conclusion.
Answer: p2 = 1.06p1
Explanation: pressure increases with temperature increase.
According to Gass law
P1/T1 = P2/T2
T1 = 20°c = 20 +273 = 293k
T2 = 40°c = 40 +373 = 313k
Therefore
P2 = P1T2/T1 = 313P2/293
P2 = 1.06P1
Answer:
- 7.48
Explanation:
Given:
Concentration of the sugar solution, C = 0.3 M
Temperature, T = 27° C = 273 + 27 = 300 K
Now,
The solute potential is given as:
solute potential = - iCRT
where,
i is the number of particles the particular molecule will make in water
i = 1 for sugar
R is the universal gas constant = 0.0831 liter bar/mole-K
on substituting the respective values, we get
solute potential = - 1 × 0.3 × 0.0831 × 300
or
The solute potential = - 7.479 ≈ - 7.48
Answer:
12.78 kJ
Explanation:
The correct balanced reaction would be
Mass of methanol = 
Moles of methanol can be obtained by dividing the mass of methanol with its molar mass 
Enthalpy change for the number of moles is given by
The change in enthalpy is 12.78 kJ.
