Cesium is a very ductile metal with the second-lowest boiling point after mercury. It is liquid at room temperature and has chemical properties similar to that of potassium. Before failure, Cesium can sustain and withstand plastic deformation under tensile stress. This makes it metal with high ductility.

In the solubility of substances, the law that “like dissolves like” is strictly adhered to. Polar compounds are therefore soluble in polar solvents and non-polar compounds are soluble in non-polar solvents. Water is a polar solvent and then an excellent solvent for polar solutes. Water cannot dissolve non-polar solutes. When polar solutes are dissolved in water, they are surrounded by water molecules and as a result of the high dielectric constant of water, the polar molecules are separated from one another and eventually get dissolved in the water.

Oxygen gas was most likely not present in the primitive atmosphere of the earth. The atmosphere of primitive earth was composed mainly of carbon dioxide and methane as a result of the high level of volcanic activity that existed then. The activities of bacteria, one of which involves their distinct photosynthetic power, was what caused the enrichment of the earth’s atmosphere with oxygen.

Basic solutions are solutions with pH higher than 7 while acidic solutions are solutions with pH lower than 7. On the pH scale, the value from 0 to 6.9 indicates that the solution is an acidic one while the value from 7.1 to 14 indicates that the solution is a basic one. With this, a higher pH means a more basic solution. A base is known to dissociate in an aqueous solution to form Hydroxide ions. A higher pH, therefore, means more concentration of Hydroxide ion and therefore, a more basic solution.

Firstly, glucose is a compound composed of twenty-four atoms of which contain carbon, hydrogen, and oxygen. Option A is wrong because glucose as a molecule cannot contain other molecules. In option B, glucose is not an element. Option C is incorrect as glucose is not an atom. A compound is composed of two or more elements. When these elements are bonded chemically to one another, a compound is formed. Glucose is a good example of a compound.

Hydrolysis is simply the process whereby substances are broken down chemically by water. This depends on the solubility, oxidation, oxidation-reduction reaction, and the pH of the compound. By hydrolysis, feldspar is altered to release hydrogen. Reaction between an ion of feldspar and a molecule of water releases a solution called Kaolinite. Kaolinite is a gray or white gray clay mineral composed of aluminum silicate hydroxide.

Ozone is made up of three oxygen atoms and is formed when sunlight and heat lead to chemical reactions between nitrogen dioxide and a volatile organic compound also known as hydrocarbons. This reaction can occur high in the atmosphere and low to the ground. As a result of the increasing amount of UV radiation emitted during the long days of summer, higher ground-level ozone occurs often. It is worthy to note that ozone is good up high and bad near the ground.

The major products of fermentation are lactic acid, ethanol, hydrogen gas, and carbon dioxide. Fermentation involves the breaking down of substances containing sugar substances using chemical means which sometimes involves microorganisms with the release of heat. The end products always include alcohol and carbon dioxide. The foaming seen in the production of wine and beer is a form of fermentation and it is a process that takes close to 10,000 years. Fermentation destroys a couple of harmful microbes and replaces them with beneficial bacteria.

A proposed explanation, formulated on the grounds of limited evidence with the aim of further investigation is known as a hypothesis. For a hypothesis to be good enough to be adopted, it must possess some distinct characteristics.

Of the options listed, a hypothesis should never be a general statement as a good hypothesis is only formulated for a specific problem and does not include generalization. A hypothesis depicting generalization cannot be used to get correct conclusions.

Sodium is the most reactive element in the options listed. With an atomic number of 11, sodium is ready to give out one electron to create a fully stable L shell and attain an octet state. When this electron is given out, it makes sodium a cation, therefore, becoming very reactive due to the positive charge. This valency of sodium tends to make it extra reactive.

When the composition of a mixture is not uniform, such a mixture is called a heterogeneous mixture. With this, it is clear that two or more different phases are required to build a heterogeneous mixture. Mixing two solids will therefore not produce one. Some examples include sand and water, kerosene and water, etc.

The scientific method is generally used when conducting experiments as well as for exploring observations. In order to discover the link or relationship between cause and effect in a variety of applications and situations, the scientific method has proven to be a standard in performing many experiments today. Observation entails asking questions on a natural phenomenon in order to formulate a hypothesis that will in turn, answer the question. To make observations, the human senses are well utilized and this sometimes makes the process ineffective as the human senses are extremely subjective leading to difficulty in comparing and recording.

Therefore, the reactants of cellular respiration are glucose and carbon dioxide.

By lowering the activation energy of the reaction, enzymes help to speed up rate of reaction without affecting the chemical composition of that reaction. Without enzymes in the body, there will be no reaction in the body as most reactions happening in the body are entirely catalytic. While the enzyme catalyzes the reaction, the substrate is the molecule which an enzyme acts on. Generally, the substrate is changed into a product or products and then released from the active site of an enzyme. So in summary, the substrate binds with the enzyme at a point called the active site, undergoes a series of chemical reactions, and then is released from the same active site as a whole new product.

Food particles are processed in aerobes by combining the food with oxygen and then diverting the energy gotten from it using the mitochondria. The energy is then stored using ATP and used in fueling other processes. . This whole process is known as cellular respiration. The first step of this process is known as glycolysis and in this step, energy is gotten from glucose in as many as ten steps. In this process, water is consumed which in turn removes it from the atmosphere. As a result of this, the water cycle is affected.

In chemical weathering, particles are disintegrated by a series of chemical reactions. Reactions like acidification, hydrolysis, oxidation, and carbonation, tend to alter the chemical composition of minerals. In limestone, rain mixes with carbon dioxide to create carbonic acid. With this, carbonation occurs and this acid flows through the limestone. A reaction is formed and calcium bicarbonate is formed. This bicarbonate solution becomes soluble in the limestone and this in turn weathers the limestone and washes it away.

The molecules upon which enzymes act are known as substrates. These substrates are later converted into different molecules known as products. Generally, enzymes, which are biological catalysts of the reactions of the body, are proteins with the ability to bind substrates in their active state and then chemically modify the bound substrate gotten to form the product of the reaction. The substrate is also known as the reactant. So, the enzyme binds with the substrate, a series of reactions happen and the product is released from the active site of the enzyme. Since enzymes are catalysts, they help in altering the rate of the reaction by lowering the activation energy of the reaction but are in no way part of the reaction itself.

The process in which a substance changes from a gaseous state to a liquid state is called condensation, so option B is the correct answer.

Absolute zero is the coldest possible temperature, where all motion stops.

Evaporation is liquid changing to gas, and at a critical temperature, a substance is liquefied.

The kind of transport system required to transport Ca2+ throughout the body is the active transport system. The Ca2+ ATPase found in the sarcoplasmic reticulum makes use of ATP as a direct energy source, hence it is classified as a form of active transport.

The glucose-Na+ transporter of intestinal epithelial cells makes use of a concentration gradient that must be created by a different transporter. The system of transport is known as the secondary active transport system. Only the primary active transport system can use ATP as energy.

To calculate the mass percentage of nitrogen in a compound, we use

Mass percentage= (mass element÷total mass of compound)×100

Nitrogen (N) is 14g/mol, and 2N Is 28g/mol

– (NH4)H2PO4= 115.02g/mol

= (14÷115.02)×100 =12.17%

– (NH4)2SO4= 132.14g/mol

= (28÷132.14)×100 =21.18%

– (NH4)2HPO4= 132.06g/mol

= (28÷132.06)×100 =21.20%

– KNO3 = 101.1g/mol

= (14÷101.1)×100 =13.84%

– NH4NO3 = 80.04g/mol

= (28÷80.04)× 100 =34.98%

– NH3 = 17g/mol

= (14÷17)×100 =82.35%

Four main principles govern the scientific method. They are:

• Making observations

• Creating a hypothesis from the observation

• Testing the hypothesis

• Draw reasonable conclusions from the hypothesis

Three of the listed principles can be found in the options above. However, the fourth option does not describe any scientific method. It is most definitely the Answer.

It is important to keep a high level of food hygiene so they do not meet materials like zinc which would erode and contaminate the food.

4. PbCO3 (s) → PbO (s) + CO2 (g)

In (2), limestone is decomposed under heating to give rise to quicklime and CO2, while (4), is the thermal decomposition of lead to produce PbO and CO2.

Explanation: In the first reaction, methane (CH4 (g)) undergoes a combustion reaction to produce CO2 and H2O.

The third reaction is a combination reaction.

For example, both acids and bases cause a chemical reaction when applied to litmus paper -acid changes blue litmus paper to red, while bases turn red litmus paper to blue.

Also, when present in concentrated amounts, both acids and bases have been known to have corrosive properties. Another similarity is that both acids and bases are soluble in water -meaning that they can be diluted to a weaker concentration when mixed with water.

Also, when dissolved in water, they both produce hydrogen ions -hydrogen ions in the case of acids, and hydroxyl ions in the case of bases. Both acids and bases are good conductors of electricity, as they are electrolytes. Both acids and bases produce extreme results when measured on a pH scale -acids measure less than 7, while bases measure above 7.

Explanation: The periodic table is divided into rows and columns. The rows run across the table from one end to the other and are called periods. The columns run from the top of the periodic table to the bottom, and each is referred to as a group.

Explanation: The overall three-dimensional folded structure of a polypeptide is referred to as the tertiary structure. The structure is due to the relationship between the R-groups of the amino acids that constitute the building blocks of proteins.

The sequence initiated by amino acids that proteins tread is what gives the three dimensional shape to the tertiary state of a polypeptide.

The bond is a major contributing factor for the three dimensional shape of the tertiary structure. This formidable bond is known as the disulfide bond, which is a special kind of chemical covalent bonding.

Explanation: The phosphorus cycle differs from other cycles because it does not particularly cycle through the atmosphere, unlike carbon.

The phosphorus that exists in the earth mostly occurs in forms except in gaseous form. This means that it is almost always found in either solid or liquid forms, and never in gaseous form.

Explanation: Unlike carbon, nitrogen, water, and phosphorus which can be converted and recycled as it moves from one level of an ecosystem’s food chain to another, energy can only be transferred from one form to another, but it can never be recycled.

However, energy is lost at each transfer.

High-spin complex ions:

4)[Co F6 ] 3- four unpaired e-‘s

5)[Mn (H2O) 6 ] 2+ five unpaired e-‘s

Low-spin complex ions:

1) [Fe (CN)6 ] 4- no unpaired e-

2) [Fe (CN)6 ] 4- one unpaired e-

3) [Co (NH3) 6 ] 2+ three unpaired e-‘s