Answer:
See the answer below
Explanation:
<u>The percentage by mass of a substance in a mixture is the ratio of the mass of the substance and the mass of the entire mixture.</u>
<em>Hence, when concentrated HNO3 is said to be 69% by mass of nitric acid, it means that the solution of the acid has 69% HNO3 and 31% water in terms of mass. More specifically, 100 g of the solution of the acid would contain 69 g of HNO3 and 31 g of water respectively,</em>
By the process of Nuclear Fission:
1) We Generate Electricity. - If the process is controlled, then we can do this. It's very better way to generate electricity. 'cause of it's many advantages, all nation wants to enhance their electricity production through this mean.
2) We Create explosive. - Again, with the help of nuclear fission we can create certain helpful bombs like Atom Bomb which will help us in war.
Hope this helps!
The correct answer to this open question is the following.
Two examples of how engineers use their knowledge of atoms to create new technologies would be the following.
1.- Engineers can develop new medicines for chronic diseases when they use their knowledge about atoms. With new technologies and different scientific approaches, this new molecular medicine can be more effective in the treatment of terrible diseases that affect humans. The challenge lies in how to make these new medicines more affordable to all kinds of people, not only rich people.
2.- Engineers can also apply their knowledge about atoms to improve the water conditions so more people can have freshwater. Engineers that specialize in the environment can research the properties of water molecules and atoms, so they can develop new ways to purify and improve the quality of water, that we know that water scarcity is a major problem in many parts of the world.
The arrow that are drawn correctly are the cool air current and the upper air current. In the sea breeze, warm air moves up because it is less dense that the cool air. The cool air moves down to replace the warm air. The land breeze current moves from the land to the sea while the sea breeze moves from the sea to the land. This creates a continuous flow of current at the sea level.
Answer:
Explanation:
Valance electrons are loosely held electrons of an atom. They are involve in chemical reaction. Consider the example of metals such as group two metals. All these have two valance electrons. They needed six electrons to complete the octet or loses two valance electrons to get complete octet. Thus its easier to remove two electrons than getting six electrons. These metals remove two electrons and form cations.
Now consider the example of nonmetals such group sixteen. They needed two electrons to get complete octet or remove six electrons to get complete octet. Thus its easier for them to get two electrons and they form anion. When group two metals cation and group sixteen anions combine they form compound and chemical reaction occur.
Group two metals also combine with halogens. Two halogens atoms combine with one alkaline earth metal atom to cancel the charge and make compound neutral.
They react with oxygen and form oxide.
2Ba + O₂ → 2BaO
2Mg + O₂ → 2MgO
2Ca + O₂ → 2CaO
Oxygen carry -2 charge while Ca, Mg and Ba +2 and make the compound neutral because charges are equal in magnitude.
With sulfur,
Mg + S → MgS
Ca + S → CaS
Ba + S → BaS
Sulfer carry -2 charge while Ca, Mg and Ba +2 and make the compound neutral because charges are equal in magnitude.
