Answer:
a solution color becoming less intense due to dilution- is not an evidence of a chemical reaction
bubbles (gas formation) - evidence of a chemical reaction
explosion or fire - evidence of a chemical reaction
changes in color- evidence of a chemical reaction
precipitation- evidence of a chemical reaction
changes in temperature - evidence of a chemical reaction
a solid liquifying - is not an evidence of a chemical reaction
solution colors mixing - is not an evidence of a chemical reaction
Explanation:
A chemical change is not easily reversible and yields new substances. It is often accompanied by a loss or gain of heat.
In the answer section, i have shown some evidences that lead us to conclude that a chemical reaction has taken place. The occurrence of a chemical change often goes with the formation of new substances as earlier stated and any of these signs may accompany the process.
For instance, when a metal is dropped in dilute acid solution, bubble of hydrogen gas indicates that a chemical reaction has taken place.
Properties of matter can be broadly classified into two categories:
Physical properties which usually involve a change in the state of matter and Chemical properties which involve a change in the chemical composition of matter.
Now, physical properties can be further classified as:
Extensive: these depend on the amount of the substance, eg: mass, volume
Intensive: these do not depend on the amount of the substance eg: density, color, melting point, boiling point
Here we are given a 5.0 g and 1 cm3 silver cube :
Therefore:
Extensive properties are-
1) Mass of silver = 5.0 g
2) Volume of silver = 1 cm3
Intensive properties are:
1) Density of silver = mass/volume = 5.0 g/ 1 cm3 = 5.0 g/cm3
2) Melting point of silver = 962 C
3) Color = white/gray
CaO because oxygen have 2 dots and calcium as well
(oxygen valency -2
calcium valncy +2)= CaO
Nucleus ,endoplasmic reticulum
Hi there!
D is true
the number of protons is same as atomic number in an atom
good luck!
