AC-HPAT Chemistry Questions With Complete Solutions.

AC-HPAT Chemistry Questions With Complete Solutions. double-displacement reaction A double displacement reaction, also known as a double replacement reaction or metathesis, is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products Precipitate precipitate is an insoluble solid that emerges from a liquid solution. The emergence of the insoluble solid from solution is called precipitation. Often the precipitate emerges as a suspension. Precipitates can form when two soluble salts react in solution to form one or more insoluble products. Energy Levels Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. As you go farther from the nucleus, electrons at higher energy levels have more energy. Electrons in the outermost energy level of an atom are called valence electrons Marquis Test The Marquis Test is commonly used for Ecstasy testing as MDMA turns the precipitate purple black. Cobalt thiocyanate is used to test for cocaine. The Cobalt is mixed with the questionable substance, then drowned in hydrochloric acid, doused in chloroform, and shaken. What is the relation between an atomic number and a mass number? Atomic number is actually the number of protons in an atom while mass number is the number of nucleons i. e, number of protons plus the number of neutrons. Isotopes Isotopes refer to the nuclides of a certain element that have different numbers of neutrons, or in other words, atomic nuclei that have the same number of protons but different numbers of neutrons. A radioisotope is an isotope that is unstable and therefore undergoes radioactive decay or will at some point. Chemical Synthesis Chemical synthesis, the construction of complex chemical compounds from simpler ones. It is the process by which many substances important to daily life are obtained. It is applied to all types of chemical compounds, but most syntheses are of organic molecules. Decomposition A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. These reactions often involve an energy source such as heat, light, or electricity that breaks apart the bonds of compounds single-displacement reaction A single-displacement reaction, also known as a single-replacement reaction, is a type of chemical reaction where an element reacts with a compound and takes the place of another element in that compound. This type of reaction is typically pictured like this: Here, A replaces B in the compound BC Flame test flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic emission spectrum. The color of flames in general also depends on temperature; see flame color. Precipitation reaction A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name. Precipitation reactions can help determine the presence of various ions in solution. organic compounds An organic compound is a substance that is added to a product, like food, to improve some qualities such as taste, smell, colour and texture. These substances can be both positive and negative for human health. Synthetic materials Synthetic materials which are by-products of petroleum are non-biodegradable, synthetic products take a long time to decompose, creating long-term pollution. Nylon is hard to recycle, making them hard to decompose, accumulate landfills more. Polyesters are easy to recycle, which makes them less harmful to the society. Electronegativity Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most commonly used. Fluorine (the most electronegative element) is assigned a value of 4.0, and values range down to caesium and francium which are the least electronegative at 0.7. Covalent bonds Covalent bonds are chemical bonds between two non-metal atoms. An example is water, where hydrogen (H) and oxygen (O) bond together to make (H2O). A full outer shell usually has eight electrons, or two in the case of hydrogen or helium. ... Covalent bonds are formed by atoms sharing valence electrons. Functional Group The functional group is defined as an atom or group of atoms joined in a specific manner, which gives the chemical properties of the organic compound and are the centers for chemical reactivity. Compounds having a similar functional group have undergone similar reactions. unique characteristics of the carbon atom in terms of covalent bonding Because each carbon is identical, they all have four valence electrons, so they can easily bond with other carbon atoms to form long chains or rings. In fact, a carbon atom can bond with another carbon atom two or three times to make double and triple covalent bonds between two carbon atoms. Alkenes Alkenes are a class of hydrocarbons (e.g, containing only carbon and hydrogen) unsaturated compounds with at least one carbon-to-carbon double bond. Another term used to describe alkenes is olefins. Alkenes are more reactive than alkanes due to the presence of the double bond Alkane an alkane, or paraffin (a historical name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon-carbon bonds are single. Alkyne An alkyne is a molecule that has a triple bond between two carbon atoms. They have general formula CnH2n-2. They are also called acetylenes. The smallest alkyne is acetylene, also called ethyne. Alkynes are hydrophobic: this means they dissolve well in organic solvents but not in water. Alcohol alcohol is an organic compound that carries at least one hydroxyl functional group (−OH) bound to a saturated carbon atom. ... An important class of alcohols, of which methanol and ethanol are the simplest members, includes all compounds for which the general formula is CnH2n+1OH. Aldehyde aldehyde is a compound containing a functional group with the structure −CHO, consisting of a carbonyl center (a carbon double-bonded to oxygen) with the carbon atom also bonded to hydrogen and to an R group, which is any generic alkyl or side chain. Ketone a ketone is a functional group with the structure RC(=O)R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond). carboxylic acid carboxylic acid is an organic compound that contains a carboxyl group (C(=O)OH). The general formula of a carboxylic acid is R-COOH, with R referring to the alkyl group. Carboxylic acids occur widely. Important examples include the amino acids and acetic acid. Ester an ester is a chemical compound derived from an acid (organic or inorganic) in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group. Usually, esters are derived from a carboxylic acid and an alcohol. Amines Amines are formally derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group (these may respectively be called alkylamines and arylamines; amines in which both types of substituent are attached to one nitrogen atom may be called alkylarylamines). Physical Properties of Oxygen: Liquid Oxygen: Oxygen bubbles rise through pale-blue liquid oxygen. Oxygen is more soluble in water than nitrogen is; water contains approximately one molecule of O2 for every two molecules of N2, compared to an atmospheric ratio of approximately one to four. Nitrogen Nitrogen is a chemical element with symbol N and atomic number 7. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.09 percent of Earth's atmosphere by volume. Additional Reactions Addition reactions occur when an atom is added to a compound that has a double or triple bond. Unsaturated compounds are associated with addition reactions. ... Atoms can also be added to molecules in an addition reaction. However, atoms or molecules will never be eliminated or removed during this process.