Answer:
Explanation:
Attach is the net ionic equation
Matter is predominantly know to exist in three states-
-Solid
-Liquid
-Gas
The three states can be interconverted at appropriate temperature and pressure conditions. Each state exhibits unique properties which are influenced by the intermolecular forces that hold the atoms together in these states.
Ans: Thus, Every time matter changes from a liquid to a gas, the matter also experiences a change in the <u>state (or phase)</u>
Answer:
Approximately 
.
Explanation:
This question can be solved using Hess's Law.
Start by considering: how can the first three reactions (with known 
values) be combined to produce the reaction 
?
Here's one possible combination:
- Include the first reaction once, without inverting.
- Invert the second reaction and include it once.
- Include the third reaction after multiplying all its coefficients by two.
In other words, if 
, 
, and 
denote the three reactions with know values, respectively, then 
will give the required reaction .
By Hess's Law, the value of the reaction will thus be:
.
Answer:
- Question 19: the three are molecular compounds.
Explanation:
<em>Question 19.</em>
All of them are the combination of two kinds of different atoms in fixed proportions.
- C₂H₄: two carbon atoms per four hydrogen atoms
- HF: one hydrogen atom per one fluorine atom
- H₂O₂: two hydrogen atoms per two oxygent atoms
Thus, they all meet the definition of compund: a pure substance formed by two or more different elements with a definite composition.
Molecular compounds are formed by covalent bonds and ionic compounds are formed by ionic bonds.
Two non-metal elements, like H-F, C - C, C - H, H-O, H - H, and O - O will share electrons forming covalent bonds to complete their valence shell. Thus, the three compounds are molecular and not ionic.
<em>Question 20. </em>Formula of copper(II) sulfate hydrate with 36.0% water.
Copper(II) sulfate is CuSO₄. Its molar mass is 159.609g/mol
Water is H₂O. Its molar mass is 18.015g/mol
Calling x the number of water molecules in the hydrate, the percentage of water is:
From which we can solve for x:
Thus, there are 5 molecules of water per each unit of CuSO₄, and the formula is:
Telephones began as large, clunky devices capable of transmitting and receiving voice messages over short distances, then evolved to lighter, transportable cellular devices capable of enabling communications over large distances. In the United States, Alexander Graham Bell receives credit for producing the first telephone in 1876. Bell established a basic system of communications allowing people to talk with each other remotely over short distances through receivers. <span>As with other technologies, phone technologies improved dramatically and rapidly following Bell's introduction of the telephone to American life. In addition to improvements in the device itself, transmissions methods improved as well. By 1900, telephone companies established communication lines through many American cities, allowing people to connect over larger distances. These lines contained special coils to reduce static and expedite transmissions. Telephone calls remained limited to local regions within the borders of the United States through 1915. Then, Alexander Graham Bell completed the first transcontinental call with Thomas Watson. Rotary phones emerged just before 1920, and a numbering plan arrived in the late 1940s to allow fast and direct connections between callers. In 1956, telephone cables permitted transcontinental calls for the first time. In the 1960s and 1970s, phone use extended to emergency service and the military. Portable phones arrived in the early 1970s; by 2000, thousands of Americans carried lightweight, compact phones wherever they went. AND THEY HAVE IPHONES NOW XDD
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