Answer:
1. an eclipse of the Sun
2. state (phase) of matter
3. 5.0 g/cm3
Explanation:
1. Eclipse of the sun occurs when the planetary bodies align in such a way that causes the moon to block sunlight from reaching the Earth. The eclipse of the Sun will be the most predictable occurrence because it follows a pattern of occurrence. Eclipse of the sun occurs after a specific period of time, hence, based on this, scientists can predict that when it will occur next using its previous pattern of occurrence.
2. Considering the following groups: Group A: water, aluminum, water vapor
Group B: gasoline, ice, air
Group C: alcohol, iron, oxygen
One would realize that each constituent of each group exists in a particular state of matter. For example, in group B, gasoline is a liquid, ice is a solid while air is a gaseous mixture. Same applies for group A and C where water and alcohol are liquids, iron and aluminum are solids, while water vapor and oxygen are gases.
This shows that the STATE (PHASE) OF MATTER was the basis of classification.
3.
Answer;
-Noble gases or Group 18 elements
Explanation;
A full valence shell is the most stable electron configuration. Group 18 elements or noble gases such as helium, neon, and argon, have a full outer, or valence, shell. Elements in other groups have partially-filled valence shells and gain or lose electrons to achieve a stable electron configuration.
They are extremely unreactive and do not form bonds with themselves. Solid helium is the the ultimate fine powder being monotomic.
M1V1=M2V2
M1 * (650 ml) = 0.675 M *450 ml
M1= (0.675 M * 450 ml) / 650 ml
M1= 0.467 M
Deep inside the core of the sun, protons can collide into eachother with enough speed that they stick together to form a helium nucleus and generate a big amount of energy at the same time.