Can you still answer these basic chemistry questions every student covers in high school? Whether you slept through class or knew your way around the beakers, take this quiz to see how well you remember high school chemistry concepts.
Electrons are minuscule particles identifiable via a characteristic negative charge. They easily transfer from most surfaces - every time you touch a doorknob, you transfer electrons!
Lightning is an example of plasma, which is a collection of super ionized particles. Plasma is usually extremely hot and an excellent source of energy.
Protons and neutrons share approximately the same mass, but protons have a positive charge and neutrons have a neutral charge.
Protons and neutrons are fused together at the heart of the atom. Electrons fill orbitals around the center, but they don't just travel in circles: electrons occupy regions of space at different distances and shapes, depending on the properties of the atom.
Noble gases are so named because they almost never interact with any other elements. In other words, they're like snobby nobles who don't want to mix with the peasants!
The Celsius temperature scale is ordered around the freezing and boiling points of water. Water freezes at 0 C and boils at 100 C.
The kinetic energy of gas particles is greater than that of molecules in the liquid or solid state. Molecules of a gas zoom around, bouncing off each other and the walls of their container.
This element has a patriotic name: it was first synthesized in America in1944 by a group of scientists working in a Chicago lab. They created it by smashing neutrons into plutonium at high speed.
The mole is a common measurement used in stoichiometric chemistry. One mole of a substance (such as water) is approximately 6.022 x 10^23 water molecules!
A combustion reaction typically includes heat. For example, burning wood or coal results in a combustion reaction.
NaOH (sodium hydroxide) and HCl (hydrogen chloride) neutralize each other, forming water and table salt. Thus, you have NaOH + HCl = H2O + NaCl.
Students often remember the formula for sulfuric acid with the macabre rhyme, "Johnny was a chemist's son, but Johnny is no more. What Johnny thought was H2O was H2SO4!"
Hydrophobic molecules are water (hydro-) fearing (-phobic). They cling to other hydrophobic molecules, such as lipids, and do not dissolve in aqueous solutions.
Helium has two protons and thus is the second atom on the periodic table, right after hydrogen. Incidentally, it's only less common than hydrogen, which is the universe's most ubiquitous element.
Electronegativity increases toward the top right of the periodic table, excluding the final eighteenth (or eighth) column. Fluorine is at the top of the seventh column, making it furthest to the right and up.
In many examples, an acid-base reaction involves the exchange of a positively charged hydrogen ion. A base must have free electrons in order to receive the hydrogen.
Supersaturation occurs when a solution has more of the solute than it could normally hold at that volume. When making rock candy, you heat the sugar solution in order to dissolve more sugar than would normally dissolve; during cooling, the sugar crystallizes into rock candy.
Metals easily give up their electrons, making it possible for electrons to quickly pass from atom to atom. When you consider how pliable metals are when heated, it's easy to understand why they're described as malleable.
Covalent bonds form most of the molecules we know today. In a covalent bond, electrons are shared between atoms to form a molecule. Ionic bonds, on the other hand, involve the transfer of electrons.
Group 2 elements (the alkaline earth metals) have two valence electrons; the Group number often (but not always) corresponds to the number of valence electrons the elements in that Group contain.
Group 1 alkali metals tend to be explosive when thrown in water. Pure sodium, for example, will produce fire and a whitish cloud upon contact with water.
The electrons in the outer orbital of an atom are its valence electrons. During a reaction, these electrons are the first to form a bond or leave the atom.
Both bases and acids are dangerous to organic matter if strong enough, but few bases corrode metals. In general, most bases are slippery and bitter. They're likely to increase, not decrease, OH.
A solution is aqueous if the reactants and products are in water (meaning water is the solvent). It doesn't matter whether it's overall acidic or basic.
For an equation to be balanced, several things must be true: you must have the same number of elements on each side of the equation, and you need to make sure there are enough electrons to complete the reaction. In the correct example, it takes four hydrogen ions and one diatomic oxygen molecule to make two water molecules.
Generally speaking, the world tends toward disorder over order, but only in terms of energy exchange. Think about melting a block of ice: adding energy decreases the order present as ice transitions into liquid form.
Phenolphthalein (pronounced fee-nawl-thay-leen) turns bright pink in the presence of a base and remains clear in an acidic solution. During a titration, careful students can detect a faint pink; adding a few more drops of base will cause an explosive hot pink color to fill the beaker.
The metal is reacting with oxygen in the air, making it easier to remember that it's an "oxidation" reaction. The important part of an oxidation-reduction reaction is the transfer of electrons.
The mnemonic helps students remember what is oxidation and what is reduction in a redox reaction. LEO means "losing electrons is oxidation" and the GER means "gaining electrons is reduction."
Since atomic number increases to the right and down, the heaviest elements are at the bottom right of the periodic table. It's easier to remember when you consider that hydrogen, the lightest element, is in the top left corner.
An anion is an atom that has a net negative charge, and a cation (pronounced "cat-eye-on") has a net positive charge. This means that an anion has more electrons than usual, and a cation has fewer electrons than usual.
Single, double and triple covalent bonds make regular appearances in chemistry. Whether it is possible for a quadruple covalent bond to form is still under debate.
Hydrogen bonding occurs when hydrogen atoms "cozy up" to oxygen or other similarly electronegative atoms. The weak link between electron-starved hydrogen and electron-rich oxygen in water molecules is why water exhibits surface tension.
Some reactions proceed forward and backward at such a rate that the ratio of reactants and products doesn't change, even if some reactant is still becoming product and vice-versa.
As long as the chemical composition isn't altered, changing the volume of the solution shouldn't effect chemical equilibrium. According to Le Chatelier's principle, chemical equilibrium will shift to counteract a change in temperature, concentration or pressure.