You can promote collisions between molecules when you increase their kinetic energy by either increasing the temperature or pressure conditions of the systems. However, it is indicated that you must not change the energy. So, we eliminate choices C and D. Choice B is contradictory to the limitation that you do not increase the concentration of the reactants. Technically, all of the choices promote frequent collisions. But due to the limitations set, the accepted answer is letter A. When you increase the surface area by using powdered reactants instead of cubes, you increase the areas for susceptibility of collisions.
Answer:
1. evaporation of ethanol
2. condensation of ethanol
Explanation:
The first and second process imply a change of phase, which is essentially a physical change because the matter change from liquid to gas and from gas to liquid respectively and it can ve reversed.
The options 3 to 6 are related to a chemical reaction because the outcomes of the process are different compounds than the ones we had at the beginning. The main reaction that implies process 3 to 6 is represented by:
C6H12O6 + impurities → 2 C2H5OH + 2 CO+ C
For option 5. burning of natural gas
, we have:
Natural gas(Mainly a mix of CH4 and C2H10) +O2→COn+H2O
Therefore, justo 1 and 2 are a physical change
Answer:
[NaCH₃COO] = 2.26M
Explanation:
17% by mass is a sort of concentration. Gives the information about grams of solute in 100 g of solution. (In this case, 17 g of NaCH₃COO)
Let's determine the volume of solution, by density
Mass of solution / Volume of solution = Solution density
100 g / Volume of solution = 1.09 g/mL
100 g / 1.09 g/mL = 91.7 mL
17 grams of solute is contained in 91.7 mL
Molarity (M) = Mol of solute /L of solution
91.7 mL / 1000 = 0.0917L
17 g / 82 g/m = 0.207 moles
Molariy = 0.207 moles / 0.0917L → 2.26M
Answer:
The answer to your question is:
a) The gold cube is larger.
b) lenght = 1.67 cm
Explanation:
Data
Platinum density 21.45 g/cm3 100 gram cube
Gold density 19.3 g/cm3 100 gram cube
Formula
density = mass / volume
a) Calculate volume
volume = mass / density
Platinum volume = 100 / 21.45 = 4.66 cm3
Gold volume = 100 / 19.3 = 5.18 cm3
b) Volume = lenght³
4.66 cm³ = lenght³
lenght = ∛4.66
lenght = 1.67 cm