Answer:-
Metalloids
Explanation:-
The stair step line is a line in the periodic table that divides the metals on one side and the non metals on the other side. So the elements which lie on the stair step line must have properties in between those exhibited by the metals and those by the non metals.
Such elements we know are called metalloids. Thus In the periodic table, the elements that are adjacent to the "stair step" are called metalloids.
Answer: Option (c) is the correct answer.
Explanation:
In liquids, molecules are held by slightly less strong intermolecular forces of attraction as compared to solids.
Hence, molecules of a liquid are able to slide past each other as they have more kinetic energy than the molecules of a solid.
As a result, liquids are able to occupy the shape of container in which they are placed. Also, liquids have fixed volume but no fixed shape.
Thus, we can conclude that liquids have a variable shape and a fixed volume.
Gold is the best pure substance. The answer is gold
4. A
because PbCl2 is an ionic compound and it's solid, so it's a substance.
It cannot be mixture, because it's a pure molecule.
5. D
despite that both substances are gases, colorless they are different molecules, so they should have different either chemical and physical properties
6. C
this substance made from W atoms and others are made from molecules
ANSWER
EXPLANATION
Given that
The energy released by the system is 12.4J
Work done on the surrounding is 4.2J
Follow the steps below to find the change in energy
In the given data, energy is said to be released to the surroundings
Recall, that exothermic reaction is a type of reaction in which heat is released to the surroundings. Hence, change in enthalpy is negative
Step 1; Write the formula for calculating change in energy
Since heat is released to the surrounding, then q = -12J
Recall, that work done by the system on the surroundings is always negative
Hence, w = -4.2J
Step 2; Substitute the given data into the formula in step 1
Therefore, the change i
