Answer:
Air is a qualified element
This lesson is the first in a three-part series that addresses a concept that is central to the understanding of the water cycle—that water is able to take many forms but is still water. This series of lessons is designed to prepare students to understand that most substances may exist as solids, liquids, or gases depending on the temperature, pressure, and nature of that substance. This knowledge is critical to understanding that water in our world is constantly cycling as a solid, liquid, or gas.
In these lessons, students will observe, measure, and describe water as it changes state. It is important to note that students at this level "...should become familiar with the freezing of water and melting of ice (with no change in weight), the disappearance of wetness into the air, and the appearance of water on cold surfaces. Evaporation and condensation will mean nothing different from disappearance and appearance, perhaps for several years, until students begin to understand that the evaporated water is still present in the form of invisibly small molecules." (Benchmarks for Science Literacy<span>, </span>pp. 66-67.)
In this lesson, students explore how water can change from a solid to a liquid and then back again.
<span>In </span>Water 2: Disappearing Water, students will focus on the concept that water can go back and forth from one form to another and the amount of water will remain the same.
Water 3: Melting and Freezing<span> allows students to investigate what happens to the amount of different substances as they change from a solid to a liquid or a liquid to a solid.</span>
Answer:
Because of oxygen toxicity.
Explanation:
Oxygen toxicity.
Oxygen has been known to cause central nervous system (CNS) toxicity when the pressure gets higher. This toxicity can cause convulsions, and this can cause the diver to drown.
The current standard maximum safe oxygen working pressure is 1.4 atm ppO2. This is equal to 56.5m/185′ when breathing air (21% O2 / 79% N). Below that depth the fraction of oxygen in a breathing gas must be reduced, and in order to maintain this maximum pressure of 1.4 ppO2, Helium must be added.
Answer:
Corrosion
Explanation:
Silver, although known as a nobble metal, is also subject to corrosion process such as having silver tarnish when exposed to sulfur and air.
Tarnishing occurs on the surfaces of some metals such as brass, copper, and silver, which results in a corroded layer. Silver tarnish occurs from the chemical reaction that takes place when silver is exposed to sulfur which results in the formation of black Ag₂S
In order to restore the original silver surface, the silver tarnish (silver sulfide) layer is removed.
We have the statement presented here as follows;
The forks shown are made of silver (Ag). Some of the silver forks shown have lost their luster - they have become tarnished. This is an example of <u>Corrosion.</u>
Answer:
9.1 = basic 1.2= very acidic 5.7= acidic
Explanation:
