Answer:
d). A catalyst lowers the activation energy for a chemical reaction.
Explanation:
From the given choices, it is true that a catalyst lowers the activation energy for a chemical reaction.
The activation energy is the energy barrier that must be overcome before a chemical reaction can occur.
Some reactions have very high activation energy and would not occur without the introduction of a catalyst.
The catalyst brings the reactants into contact by removing the energy deficiency in the system.
Answer:
See explanation
Explanation:
The periodic table shows the atomic number and mass number of each element.
We know that the atomic number shows;
- The number of protons in the nucleus of the atom
- The number of electrons in the neutral atom of the element.
So we obtain the number of protons and electrons by looking at the atomic number shown in the periodic table.
We also know that;
Mass number = Number of protons + number of neutrons
Since number of protons = atomic number of the atom
Number of neutrons = Mass number - atomic number
Hence we obtain the number of protons by subtracting the atomic number from the mass number given in the periodic table.
Answer:
NaCl will only conduct electricity in solutions
Explanation:
For electrical conduction, free mobile electrons as seen in most metals must be present or ions which are charged particles must be available for solutions and molten substances.
- Sodium chloride is an ionic compound without free mobile electrons or ions despite being ionic.
- It will maintain a subtle and unique charge stability when in solid form.
- In solid, the ions are not free to move and remain locked up in the solid mass.
- When introduced into a solution, the ions becomes free to move and this will aid electrical conduction.
Answer:
I am pretty sure it is visible light
When HCl reacts with a metal, hydrogen gas will be evolved. To test this gas, insert a burning splinter into the outlet of gas, the flame will be extinguished with a pop sound. This will confirm the gas is hydrogen.
