Answer:
Explanation:
There are two kind of substances that may be classified as pure substances: elements and compounds.
Elements are the pure substances whose atoms are all of the same kind (same atomic number). Some xamples of pure substances are sodium (Na), oxygen gas (O₂), hydroge gas (H₂), nitrogen gas (N₂), helium (He), and gold (Au). There are 118 known elements. You can find all of them in a periodic table.
Elements cannot be broken down into simpler substances by chemical or physical means because the simplest substance is the atom.
The only way to break elements into other substances is by nuclear reactions: fission and fusion reactions transform the atoms of an element into different atoms, but those reactions are not considered either chemical or physical changes. Nuclear reactions are a completely different kind of changes.
On the other hand, the other kind of pure substances, compounds, are formed by two or more different elements, and they can be broken down into simpler substances by chemical means. For example, water molecules (H₂O) can be broken down into the elements that constitue them, i.e. hydrogen and oxygen.
An element is a pure substance that cannot be broken down into simpler substances by chemical or physical means. The other options - mineral, chemical, and atom - are not exact fits for the description provided in the question.
An element (option a) is the Correct response to the question. An element is a pure substance that cannot be broken down into simpler substances by chemical or physical means. Elements are the basic building blocks of matter and each element has its own unique atomic structure.
For example, gold, oxygen, and helium are all examples of elements. They each have unique properties and cannot be further broken down into simpler substances through ordinary physical or chemical methods.
The other options - mineral, chemical, and atom - do not accurately fit the description given. A mineral is typically a solid substance with a specific chemical composition and crystalline structure. A chemical may refer to a compound or substance produced by a chemical process. An atom is the smallest unit of an element, but it itself can be divided into protons, neutrons, and electrons.
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Answer:
T = 291 K
Explanation:
(2) 137Cs (4) 220Fr
Answer: The correct option is 4.
Explanation: All the options will undergo some type of radioactive decay processes. There are 3 decay processes:
1) Alpha decay: It is a decay process in which alpha particle is released which has has a mass number of 4 and a charge of +2.
2) Beta-minus decay: It is a decay in which a beta particle is released. The beta particle released has a mass number of 0 and a charge of (-1).
3) Beta-plus decay: It is a decay process in which a positron is released. The positron released has a mass number of 0 and has a charge of +1.
For the given options:
Option 1: This nuclei will undergo beta-plus decay process to form
Option 2: This nuclei will undergo beta-minus decay process to form
Option 3: This nuclei will undergo a beta minus decay process to form
Option 4: This nuclei will undergo an alpha decay process to form
Hence, the correct option is 4.
B. 3 billion years
C. 4 billion years
D. 4.5 billion years
Metal oxides M2O, peroxide M2O2, and superoxide MO are produced by alkali metals. Metal oxide is also referred to as basic oxide since basic hydroxide is the end result of interactions between metal oxide and water. As a result, their combination with acid produces salt and water in a manner similar to a regular acid-base reaction.
One of the most significant and well-characterized solid catalysts is metal oxide. Metal oxides are used in acid-base and redox processes and are regarded as heterogeneous catalysts.
Several metals are separated from their naturally occurring compounds like oxide and chloride using a breakdown reaction.
Metal oxides are crucial in various additional applications, such as energy production, conversion, and storage, as well as in environmental remediation and pollution monitoring.
Because they react with weak acids to produce salt and water, metallic oxides are basic in nature. They further react with water to create metal hydroxides, which are naturally alkaline due to the production of OH- ions in solution.
Thus, Metal oxides M2O, peroxide M2O2, and superoxide MO are produced by alkali metals.
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c. water
b. carbon dioxide
d. heat
A reaction in which the reactants splits to produce two or more products is called a decomposition reaction.
It can be represented as:
XY ------> X + Y
The correct answer is:
Option A. Sucrose
This can be explained as:
C₁₂H₂₂O₁₁ (Sucrose) + 12 O₂ -----> 12 CO₂ (Carbon dioxide) + 11 H₂O (water)
Therefore, sucrose is the reactant.
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2) ICI
3)PCI
4) HCI
Ionic bonds are formed between a metal and non-metal. Among the given compounds, KCl is the ionic compound formed from potassium metal and chlorine.
Ionic compounds are formed by electron lose and gain between metals and non-metals. Ionic bond is the strongest type of bond.
Metals are rich in electrons and they are electropositive. They will easily lose electrons to a non-metal to form an ionic bond. Non-metals with significant electronegativity are electron deficient and they will gain electrons from metals.
Potassium is an alkali metal in the first group and chlorine is a gas in the 17th group called halogen group. They form an ionic bond by losing electron from potassium and thus KCl is an ionic compound.
All compounds here, other than KCl are covalent compounds. Thus option 1 is correct.
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