Questions and Answers - Recent questions and answers in Chemistry

Answered: What is the fourth most abundant element in the universe in terms of mass?

Tue, 05 Nov 2019 09:45:31 +0000

According Wikipedia it would be Carbon, because it is the 4th most abundant and it has quite a lot of mass compared to other ones like Hydrogen

Answered: True or false? A proton carries a positive charge

Tue, 05 Nov 2019 09:43:52 +0000

A proton has positive charge of 1, that is, equal but opposite to the charge of an electron. A neutron, like the name implies, is neutral with no net charge. The charge is believed to be from the charge of the quarks that make up the nucleons (protons and neutrons).

Answered: Atoms of the same chemical element that have different atomic mass are known as?

Tue, 05 Nov 2019 09:42:13 +0000

Atoms of chemical elements having same atomic mass but a different atomic number are called Isobars. The sum of the number of protons and neutrons together form the atomic mass. Therefore, we can also say the number of nucleons present in the nucleus is equal to the atomic mass of an atom.

Answered: Is sodium hydroxide (NaOH) an acid or base?

Tue, 05 Nov 2019 09:40:30 +0000

NaOH, or sodium hydroxide, is a compound. A compound is classified as either an acid, base, or salt. All bases contain OH- (hydroxide) ions, while all acids contain H+ (hydrogen) ions.

Answered: True or false? Bases have a pH level below 7.

Tue, 05 Nov 2019 09:26:34 +0000

Acids and bases are assigned a value between 0 and 14, the pH value, according to their relative strengths. Pure water, which is neutral, has a pH of 7. A solution with a pH less than 7 is considered acidic, and a solution with a pH greater than 7 is considered basic, or alkaline.

Answered: What is the name given to substances that are initially involved in a chemical reaction?

Tue, 05 Nov 2019 09:25:11 +0000

The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants.

Answered: What is the third most common gas found in the air we breathe?

Tue, 05 Nov 2019 09:23:58 +0000

It is also one among the noble gases. The noble gas Argon is the third most common gas in the air we breath. Argon is the gas. Argon is the third most common gas found in the atmosphere.

Answered: What is H20 more commonly known as?

Tue, 05 Nov 2019 09:22:21 +0000

The chemical name of H2O is Dihydrogen Monoxide. Its commonly known as water. It is a liquid compound at room temperature.

Answered: A nuclear reaction where the nucleus of an atom splits into smaller parts is known as nuclear fission or nuclear fusion?

Tue, 05 Nov 2019 09:21:14 +0000

Fission and Fusion. The energy harnessed in nuclei is released in nuclear reactions. Fission is the splitting of a heavy nucleus into lighter nuclei and fusion is the combining of nuclei to form a bigger and heavier nucleus. The consequence of fission or fusion is the absorption or release of energy.

Answered: True or false? A neutron has no net electric charge.

Tue, 05 Nov 2019 09:19:21 +0000

A neutron, like the name implies, is neutral with no net charge. The charge is believed to be from the charge of the quarks that make up the nucleons (protons and neutrons). ... A neutron is made up of two Down quarks with a negative 1/3 charge each and one Up quark with a positive 2/3 charge.

Answered: At room temperature, what is the only metal that is in liquid form?

Tue, 05 Nov 2019 09:16:19 +0000

Liquid metal consists of alloys with very low melting points which form a eutectic that is liquid at room temperature. The standard metal used to be mercury, but gallium-based alloys, which are lower both in their vapor pressure at room temperature and toxicity, are being used as a replacement in various applications.

Answered: What orbits the nucleus of an atom?

Tue, 05 Nov 2019 09:14:53 +0000

The nucleus is orbited by the third type of subatomic particle, electrons. ... Electrons exist in an "electron cloud," which consists of the highly energetic orbits of these particles as they surround the nucleus.

Answered: K is the chemical symbol for which element?

Tue, 05 Nov 2019 09:13:04 +0000

Potassium was discovered in 1807 and named for potash, the substance from which potassium was first isolated. Potassium's symbol, K, comes from kalium, the Latin word for potash.

Answered: What is the chemical symbol for gold?

Tue, 05 Nov 2019 09:11:10 +0000

Gold is a chemical element with the symbol Au (from Latin: aurum) and atomic number 79, making it one of the higher atomic number elements that occur naturally. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal.

Answered: Famous New Zealand scientist Ernest Rutherford was awarded a Nobel Prize in which field

Tue, 05 Nov 2019 09:09:11 +0000

Chemist and physicist Ernest Rutherford was born August 30, 1871, in Spring Grove, New Zealand. A pioneer of nuclear physics and the first to split the atom, Rutherford was awarded the 1908 Nobel Prize in Chemistry for his theory of atomic structure.

Answered: True or false? An electron carries a positive charge

Tue, 05 Nov 2019 09:06:49 +0000

Electron does not carries a positive charge. Proton carries the positive charge and electron carries negative charge so atoms of elements are neutral. ... Atoms differs from one another according to the varied number of protons, neutrons as well as electrons

Answered: What is the main gas found in the air we breathe?

Tue, 05 Nov 2019 09:05:42 +0000

Oxygen only makes up about 21% of air. About 78% of the air you breathe is made up of another gas called nitrogen. There are also tiny amounts of other gases like argon, carbon dioxide and methane.

Answered: True or false? Acids have a pH level below 7

Tue, 05 Nov 2019 09:03:35 +0000

A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic. The pH scale is logarithmic and as a result, each whole pH value below 7 is ten times more acidic than the next higher value

Answered: What is the centre of an atom called?

Tue, 05 Nov 2019 07:13:54 +0000

An atom a fundamental piece of matter. ... An atom itself is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of the atom called the nucleus and the electrons fly around above the nucleus in a small cloud.

Answered: What is the first element on the periodic table?

Tue, 05 Nov 2019 07:10:36 +0000

The elements are ordered by atomic number, which is the number of protons in the nucleus -- and atomic number 1 is hydrogen.

Write the structure and function of nervous system.

Fri, 23 Nov 2018 00:34:04 +0000

Write the structure and function of nervous system.

Answered: Explain reflex action with an example.

Fri, 23 Nov 2018 00:33:03 +0000

The reflex arc describes a sequence of events leading to an action that takes place rapidly in response to a stimulus without having to think about it i.e. without an impulse travelling to the brain for coordination. For example, the response to touching a sharp object is to remove your finger from it quickly.

Answered: Describe the relationship between chromosomes,genes and DNA.

Fri, 23 Nov 2018 00:31:28 +0000

Chromosomes are paired long chains within a cell nucleus that are composed of genes (about 20,000 genes perchromosome pair), which are made up of the chemical substance called DNA.

Answered: Explain mitosis.

Fri, 23 Nov 2018 00:13:48 +0000

In cell biology, mitosis is a part of the cell cycle when replicated chromosomes are separated into two new nuclei. Cell division giving rise to genetically identical cells in which the chromosomes number is maintained

Write a detailed note on human brain?

Fri, 23 Nov 2018 00:09:57 +0000

Write a detailed note on human brain?

Answered: In which cell NaOH is manufactured?

Thu, 22 Nov 2018 23:54:03 +0000

Nelson's cell

Answered: What do you mean by stain less steel?

Thu, 22 Nov 2018 23:52:00 +0000

"The best example of alloying is the "stain less steel" which is a good combination of iron, chromium and nickel.

Answered: Why alkali metals are more reactive than alkaline earth metals?

Thu, 22 Nov 2018 23:49:59 +0000

Alkali metals are more reactive than alkaline earth metals. This is because they have low ionization energies than alkaline earth metals

Answered: Define supersaturated solution?

Thu, 22 Nov 2018 23:45:08 +0000

A solution that is more concentrated than a saturated solution is called super saturated solution.

Answered: What are the use of Silver?

Thu, 22 Nov 2018 23:44:03 +0000

1) Alloys of silver with copper are used in making coins, silver wares and ornaments.

2) Compounds of silver are used on photographic films and in filling teeth.

3) Its compounds are used in mirror industry

Answered: Why reactivity of metals increases down the group?

Thu, 22 Nov 2018 23:32:48 +0000

Reactivity of metals increases down the group because down the group, size of atoms increases due to addition of shells. When the shells are added and the size of atoms increases the electropositive character or metallic character increases due to which it becomes easier to lose it valence electrons.

Answered: How does the nature of attractive force of solute-solute and solvent-solvent affect the solubility?

Thu, 22 Nov 2018 23:31:42 +0000

If attractive forces between solute particles are strong enough than solute-solvent forces, solute remains insoluble and solution is not formed.

Answered: Does the percentage calculation require the chemical formula of the solute?

Thu, 22 Nov 2018 23:30:29 +0000

The percentage calculations does not require the chemical formula of the solute. This is because molar mass is not required in these calculations.

Answered: Define molarity?

Thu, 22 Nov 2018 23:29:10 +0000

The number of moles of solute dissolved in one dm³ of solution is called morality. It is represented by M

Answered: Which group of metals are highly reactive?

Thu, 22 Nov 2018 23:27:50 +0000

The highly reactive group of metals is Group I.

Write down uses of calcium

Thu, 22 Nov 2018 23:25:13 +0000

Write down uses of calcium

Answered: How you make relationship of solution to different products in the community? Explain briefly

Thu, 22 Nov 2018 23:23:59 +0000

Our body is made up of tissues, which are all composed of water based chemicals. The water becomes the best solvent in our body. We need an adequate supply of chemicals in the form of food. vitamins, hormones and enzymes. For taking care of our health we need medicines.

Answered: Define solute? Give an example.

Thu, 22 Nov 2018 23:22:26 +0000

The component of solution which is presented in smaller quantity is called solute. I

n sugar solution, sugar is solute, in sodium chloride solution, sodium chloride is solute, in copper sulphate solution, copper sulphate is solute, in air excepts N ₂ all other gases are solutes.

Answered: Write four physical properties of Metals.

Thu, 22 Nov 2018 23:19:36 +0000

1. They are made into jewellery due to their hard and shiny appearance.

2. They are used to make pans, since they are good conductors of heat.

3. They are used in electrical cables, because they are malleable, ductile and good conductors of electricity.

4. They are strong so used to build scaffolding and bridges.

5. They make a ringing sound, sonorous, hence their use in bell making.

Answered: Define the characteristic of solution?

Thu, 22 Nov 2018 23:17:56 +0000

1. The particles exist in their simplest form i.e. as molecules or ions. Their diameter is10-s cm.

2. Particles are so small that they can't be seen with naked eye.

3. Solute particles can pass easily through a filter paper.

Write the preparation of molar solution?

Thu, 22 Nov 2018 23:16:05 +0000

Write the preparation of molar solution?

Answered: How can you justify that milk is a colloid?

Thu, 22 Nov 2018 23:14:12 +0000

Milk is a colloid. This is because

1. If appears to be a homogeneous mixture but actually it is a heterogeneous mixture.

2. Particles do not settle down for a long time. Therefore, it is quite stable.

3. Particles are large but cannot be seen with naked eye.

4. Although particles are big but they can pass through a filter paper.

5. It shows a Tyndal effect.

Answered: Why the Oxygen is called nonmetal?

Thu, 22 Nov 2018 23:12:30 +0000

Oxygen is a nonmetal. This is because it has low boiling and melting points, no luster, neither malleable nor nor ductile, poor conductor of heat and electricity, low density, gas at room temperature. Chemically, it has a tendency to form negative ions when it reacts with metals.

Answered: What is the simplest way to distinguish between a solution and pure liquid.

Thu, 22 Nov 2018 23:01:08 +0000

The simplest way to distinguish between a solution and a pure liquid is evaporation. The liquid which evaporates completely, leaving no residue is a pure compound, while a liquid which leaves behind a residue on evaporation is solution.

Answered: What is an aqueous solution?

Thu, 22 Nov 2018 22:58:36 +0000

7.5: Aqueous Solutions and Solubility: Compounds Dissolved in Water. When some substances are dissolved in water, they undergo either a physical or a chemical change that yields ions in solution. These substances constitute animportant class of compounds called electrolytes.

Answered: What is the shape of Cathode in Nelson's Cell? Why is it perforated?

Thu, 22 Nov 2018 22:55:42 +0000

The shape of cathode in Nelson's cell is U-shaped.

The cathode is made perforated to percolate sodium hydroxide solution slowly into a catch basin.

Answered: Which force drives the non spontaneous redox reaction to take place?

Thu, 22 Nov 2018 22:54:09 +0000

The force which drives the non spontaneous redox reaction to take place is electric current using a source of electric current (DC battery).

Answered: Define electrolytic cell.

Thu, 22 Nov 2018 22:52:57 +0000

The type of electrochemical cell in which a non-spontaneous redox reaction is carried out by passing electric current is called electrolytic cell." "

An electrochemical cell in which electrolysis occurs is called electrolytic cell."

Answered: When the solute settles down at bottom of container?

Thu, 22 Nov 2018 22:50:45 +0000

When a small amount of solute is added in a solvent, solute dissolves very easily in the solvent. If the addition of solute is kept on, a stage is reached when solvent cannot dissolve any more solute. At this stage, further added solute remains undissolved and it settles down at the bottom of container.

Answered: Explain with an example that solubility of salt increase with the increase of temperature?

Thu, 22 Nov 2018 22:49:12 +0000

As the salt dissolves, the positive and negative ions are pulled apart and become surrounded by water molecules. ... Forexample, sugar and salt are more soluble in water at highertemperatures. But, as the temperature increases, the solubilityof a gas in a liquid decreases.