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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The two compounds present in unpolluted air are carbon dioxide and water. You may think that carbn dioxide is a greenhouse gas, yes it is and at the same time not. There animals in the earth that produces carbon dioxide into the atmosphere, the carbon dioxide too, is also need for plan respiration.
Unpolluted air contains small amounts of various compounds. Examples include Carbon Dioxide (CO2) which is used in the process of photosynthesis and Argon (Ar) which remains chemically inactive.
Unpolluted air primarily consists of nitrogen and oxygen, but it also contains small amounts of other gaseous compounds. Two of these compounds found in unpolluted air are carbon dioxide (CO2) and argon (Ar). Carbon dioxide (CO2), which is produced by animals during respiration and used by plants during photosynthesis, and argon (Ar), a noble gas, which is chemically inert and does not directly affect the climate or living organisms.
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concentration of calcium ions in this solution is
(1) 4.3 ppm (3) 17 ppm
(2) 8.5 ppm (4) 34 ppm
60 ml of a 0.40 m solution of h2so4 is used to neutralize 0.3 m magnesium hydroxide solution, the volume of NaOH required to neutralize the given amount of Mg(OH)2 is 160 ml.
To answer this question, we need to use the concept of stoichiometry. Stoichiometry is the calculation of the quantities of reactants and products in a chemical reaction. The balanced chemical equation for the neutralization reaction between sulfuricacid (H2SO4) and magnesium hydroxide (Mg(OH)2) is:
H2SO4 + Mg(OH)2 → MgSO4 + 2H2O
From the equation, we can see that one mole of H2SO4 reacts with one mole of Mg(OH)2. Therefore, the number of moles of Mg(OH)2 in 60 ml of 0.3 m solution is:
moles of Mg(OH)2 = concentration x volume = 0.3 x (60/1000) = 0.018 moles
Since one mole of Mg(OH)2 requires one mole of NaOH to neutralize it, we need 0.018 moles of NaOH. The concentration of the NaOH solution is not given, so we cannot directly calculate the volume of NaOH required. However, we can use the concentration and volume of the H2SO4 solution to find the number of moles of H2SO4 used in the neutralization reaction:
moles of H2SO4 = concentration x volume = 0.40 x (60/1000) = 0.024 moles
From the balanced equation, we know that one mole of H2SO4 reacts with two moles of H2O. Therefore, the number of moles of H2O produced in the reaction is:
moles of H2O = 2 x moles of H2SO4 = 0.048 moles
Since the reaction is neutralization, the same number of moles of H2O and H+ ions are produced. Therefore, the number of moles of H+ ions produced is also 0.048 moles. Each mole of NaOH can neutralize one mole of H+ ions. Therefore, the number of moles of NaOH required is:
moles of NaOH = 0.048 moles
If we assume that the concentration of the NaOH solution is also 0.3 m, then the volume of NaOH required is:
volume of NaOH = moles of NaOH / concentration = 0.048 / 0.3 = 0.16 L = 160 ml
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Answer: This is an incomplete combustion reaction.
Explanation:
Combustion reaction is defined as the reaction in which a hydrocarbon produces carbon dioxide gas and water molecule when reacted with oxygen gas. General equation for this reaction is:
Incomplete combustion is also a reaction between oxygen and hydrocarbon in which the products obtained are carbon monoxide, water and carbon. This type of combustion happens when there is insufficient supply of oxygen gas. General equation for this reaction is:
Hence, the hydrocarbon is undergoing an incomplete combustion reaction.
When 150 ml of 0.500 M silver nitrate are added to 100 mL of 0.400 M potassium chromate, a silver chromate precipitate forms. Considering the stoichiometry of the reaction and the quantities of reactants, 24.88 grams of silver chromate will precipitate.
The subject of this question is based on precipitation reactions in Chemistry. Precipitation reactions occur when two solutions combine to form an insoluble solid known as a precipitate. The moles of silver nitrate present in a 150 mL of 0.500 M solution can be calculated using the formula Molarity = Moles ÷ Volume (in Litres).
Thus, Moles of AgNO3 = 0.500 M * 0.15 L = 0.075 mol AgNO3. According to the reaction equation 2AgNO3 + K2CrO4 → 2AgCrO4(precipitate) + 2KNO3, for every mole of K2CrO4, we have two moles of AgNO3. Thus, based on stoichiometry and the given quantities of the reactants, the limiting reactant will be AgNO3, and it will totally react and form the silver chromate precipitate. The moles of Ag2CrO4 formed would therefore also be 0.075 mol. To convert this into grams, we use the molar mass of Ag2CrO4, which is approximately 331.73 g/mol. Hence, grams of Ag2CrO4 = 0.075 mol Ag2CrO4 * 331.73 g/mol = 24.88 g Ag2CrO4.
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