Answer:
Combining the two clear colorless liquids is a chemical change.
Explanation:
Because a different solid substance is formed. Tell students that a precipitate is an insoluble solid that forms when two solutions are combined and react chemically. Insoluble means that the solid will not dissolve.
Answer: 27 neutrons
Explanation:
Recall that the number of protons in the nucleus of an atom = Atomic number.
Hence, Calcium with mass number 47 and atomic number 20 will have 20 protons
Therefore, since Mass number = number of protons + neutrons
47 = 20 + neutrons
Neutrons = 47 - 20 = 27
Thus, there are 27 neutrons in radioactive calcium nucleus.
Answer:
74mL
Explanation:
Given parameters:
Molar mass of citric acid = 192g/mol
Molar mass of baking soda = 84g/mol
Concentration of citric acid = 0.8M
Mass of baking powder = 15g
Unknown parameters:
Volume of citric acid = ?
Solution
Equation of the reaction:
C₆H₈O₇ + 3NaHCO₃ → Na₃C₆H₅O₇ + 3H₂O + 3CO₂
Procedure:
- We work from the known parameters to the unknown. From the statement of the problem, we can approach the solution from the parameters of the baking powder.
- From the baking powder, we can establish a molar relationship between the two reactants. We employ the mole concept in this regard.
- We find the number of moles of the baking powder that went into the reaction using the expression below:
Number of moles =
Number of moles = = 0.179mole
- From the equation of the reaction, we can find the number of moles of the citric acid:
3 moles of baking powder reacted with 1 mole of citric acid
0.179 moles of baking powder would react with :
This yields 0.059mole of citric acid
- To find the volume of the citric acid, we use the mole expression below:
Volume of citric acid =
Volume of citric acid = = 0.074L
Expressing in mL gives 74mL
Answer:
Explanation:
In the solution of AB , they are split to give ions as follows
AB ⇄ A⁺ + B⁻
Product of concentration of A⁺ and B⁻ in saturated solution of AB is constant .
This is called Ksp
Ksp = [A⁺] [ B⁻]
If product of concentration of A⁺ and B⁻ exceeds Ksp , the equilibrium shifts to the left side and excess ions come out of solution in the form of precipitate. So second option is the answer.
A decomposition reaction should look like
A ------> B +C+...
It has to have only one reactant and several products.
2 NO2 ⟶ 2 O2 + N2