A spherical ball of lead has a diameter of 2.5 cm . What is the mass of the sphere if lead has a density of 11.34 g/cm3? (The volume of a sphere is (43)πr3 where r is the radius.)

Answer : The volume of of rectangle is,

Explanation : Given,

Length of rectangular solid = 1.0 m

Width of rectangular solid  = 5.6 cm = 0.056 m

conversion used : (1 cm = 0.01 m)

Height of rectangular solid = 2.1 mm = 0.0021 m

conversion used : (1 mm = 0.001 m)

Formula for volume of rectangle :

where,

V = volume of rectangular solid

l = length of rectangular solid

b = width of rectangular solid

h = height of rectangular solid

Now put all the given values in the above formula, we get:

Therefore, the volume of of rectangle is,

Answer:

To determine the number of constitutional isomers of C4H9Br, we can generate different structures by rearranging the atoms. The molecular formula C4H9Br implies a carbon chain with four carbon atoms, and one bromine atom.

Here are the constitutional isomers for C4H9Br:

1. **n-Butyl Bromide**: This is the straight-chain isomer where the bromine atom is attached to the end carbon atom.

2. **Isobutyl Bromide**: This is an isomer with a branched chain. The bromine atom is attached to one of the middle carbon atoms in the chain.

3. **sec-Butyl Bromide**: Another branched isomer where the bromine atom is attached to one of the middle carbon atoms but in a different position compared to isobutyl bromide.

4. **tert-Butyl Bromide**: This isomer has a highly branched structure where the bromine atom is attached to a carbon atom that is part of a tertiary (3°) carbon center.

So, there are four constitutional isomers of C4H9Br. Therefore, the correct answer is (c) Four.

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The answers are (1) and (3). Because the number of atoms in magnesium is 12.

Further Explanation

The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus. The amount is identical to the amount of charge in the core. The atomic number uniquely identifies chemical elements. In uncharged atoms, the atomic number is also the same as the number of electrons. The sum of atomic numbers Z and the number of neutrons N gives the mass number A of an atom. Because protons and neutrons have roughly the same mass (and the mass of electrons is ignored for many purposes) and nucleon bond energy is always small compared to nucleon mass, when the atomic mass of each atom is expressed in units of integrated atomic mass (into a quantity called "mass relative isotope "), worth about 1% of all A. numbers. Atoms with the same atomic number Z but neutron N numbers are different, and therefore have different atomic masses, known as isotopes. More than three-quarters of the elements present in nature are in a mixture of isotope conditions, and the average mass of the isotope for the mixture of isotopes of an element (called relative atomic mass) in the environment on Earth, determines the standard atomic weight of the element. Historically, the weight of these atomic elements (compared to hydrogen) is the amount that can be measured by chemists in the 19th century.

The writing of the elemental symbol was introduced in the Middle Ages by John Dalton (1810) who made a very simple elemental symbol as a circle. Along with the development of the discovery of the element J.J Berzelius (1779-1848) made the symbol of the element that is used as the basis for writing the element symbol until now, with the provisions: one symbol element consisting of one letter, then the writing must be in capital letters. Two symbol elements consisting of two letters, then the writing with capital letters in the first letter, and lowercase letters for the second.

The chemical formula of a substance states the type and the relative number of atoms contained in that substance. The number that states the number of atoms of an element in a chemical formula is called the index number. Chemical formulas may be either molecular formulas or empirical formulas.  

The formula could be a formula that states the number of atoms of the weather that frame one molecule of a compound. So the molecular formula expresses the actual arrangement of matter molecules.

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Details

Grade: High School

Subject: Chemistry

keywords: The atomic number

Answer: Option (b) is the correct answer.

Explanation:

Insulator are the substances which do not conduct electricity. It is known that metals are good conductors of electricity. Whereas non-metals do not conduct electricity.

Out of the given options, silver, and calcium is a metal that means they are good conductors of electricity and are not insulators.

On the other hand, silicon is a metalloid, that is, it shows properties of both metals and non-metals. Hence, it will also show conductivity.

Phosphorus is a non-metal and therefore, it does not conduct electricity. As a result, out f the given options it will act as the best insulator.