You are to convert 3.55 moles of NaCl to formula units. Always remember that the Avogadro’s number is 6.023*10^23 units per mole of a substance. Units could be atoms, molecules or formula units. So, just multiply 3.55 moles to 6.023*10^23 formula units per mole and you will get 2.138x10^24 formula units of NaCl.
The substance that cannot be broken down by chemical change is .
Further Explanation:
Substance is the pure form of matter while a combination of atoms or molecules is termed as mixture.
Types of substances:
1. Element
The simplest form of substance that cannot be further decomposed by any chemical means is called an element. Carbon, sulfur, and cobalt are some of the examples of elements.
2. Compound
When two or more different elements are held together by chemical methods, compounds are formed. These can further be decomposed into their corresponding constituents. The properties of compounds are very different from those of their constituent elements. NaCl, and are examples of compounds.
(1) Ammonia is composed of one nitrogen and three hydrogen atoms so it is a compound. Therefore it can be broken down by chemical change.
(2) Mercury is an element so it is the simplest form in which it can exist. Therefore it cannot be broken down by chemical change.
(3) Propane is composed of three carbon and eight hydrogen atoms so it a compound. Therefore it can be broken down by chemical change.
(4) Water is composed of one oxygen and two hydrogen atoms so it is a compound. Therefore it can be broken down by chemical change.
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Answer details:
Grade: High School
Subject: Chemistry
Chapter: Elements, compounds, and mixtures
Keywords: substance, mercury, propane, water, ammonia, element, compound, chemical change, decomposed, simplest form, NaCl, CH4, carbon, sulfur, cobalt.
The substance which cannot be broken down by a chemical change is mercury as it is an element, hence option 2 is correct.
It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.
Thus, option 2 which is mercury is correct as it is an element.
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7.0
8.0
10.0
Answer: 2.0 (acidic solution)
Explanation: When a salt is formed by the reaction of strong acid and a weak base , it will be acidic in nature and thereby its pH will be less than 7.
In the process, conjugate acid will be formed which will react with water to give the hydronium ion (H_{_{3}}O ^{+})
Thus as the positive ion species is increasing, it will make the solution acidic in nature.
The pH value of a salt that is formed by the reaction of a strong acid and a weak base is: 2.0 (acidic solution)
pH value is a value on the pH scale that tells us how acidic or basic a solution can be.
When a salt is formed by the reaction of strong acid and a weak base , it will be acidic in nature and thereby its pH will be less than 7.
In conclusion, The pH value of a salt that is formed by the reaction of a strong acid and a weak base is: 2.0 (acidic solution)
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Answer:
A carbon-14 atom has 6 protons, 8 neutrons and 6 electrons. The number 12 or 14 in the name of carbon-12 and carbon-14 refers to their atomic mass.
Explanation:
Those atoms that have the same "atomic number" but differente "atomic mass" (or atomic weight) are called isotopes.
Atomic number indicates the amount of electrons that an atom has, which matchs with the number of protons it has.
Atomic mass indicates the sum of protons and neutrons that an atom has.
Example with carbon-12:
carbon atomic number = 6 (find this information in a periodic table)
electrons= 6
protons= 6
carbon atomic mass = 12 (find this information in a periodic table)
neutrons= atomic mass - number of protons= 12-6 = 6 neutrons
Using the same analysis for carbon-14:
carbon atomic number = 6
electrons= 6
protons= 6
carbon atomic mass = 14
neutrons= atomic mass - number of protons = 14-6 = 8 neutrons
In this way, carbon-14 is an isotope of carbon-12 because carbon-14 has the same atomic number than carbono-12 but different atomic mass.
a. True
b. False?
CO which is carbon monoxide is a primary pollutant for air pollution. As it contributes to the major proportion in the air pollutants amongst others. It has 48% percent of pollutants in comparison to other pollutants of air. The source of carbon monoxide is mainly from incomplete combustion of fuel mostly from the older cars.
The rise in atmospheric CO results in fatigue, drowsiness and my also sometimes lead to death of the person exposed to it.
The statement is true. Carbon monoxide (CO) is a primary pollutant, which is directly emitted into the environment from vehicles and machines burning fossil fuels and can negatively impact our health by limiting the oxygen transportation in the body.
Yes, the statement 'CO is a primary pollutant' is True. Primary pollutants are those that are directly emitted into the environment and have a damaging effect. Carbon monoxide (CO) is a significant primary pollutant that is largely produced by vehicles and other machines that burn fossil fuels. It is harmful because, when inhaled, CO can limit your body's ability to transport oxygen in your bloodstream, leading potentially to serious health problems.
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A digital thermometer is more preferable than a liquid-based thermometer because it gives accurate data than the liquid thermometer. Liquid thermometer is affected by the temperature, and when it does, the liquid expands and so des the material covering the thermometer. For the digital thermometer, it has less error because it already has a sensor inside it that determines the temperature of the substance.