6. First, write a preliminary equation for the reaction. V2O5 and H2 are the reactants, and V2O3
and H2O are the products.
Next, count the number of atoms of each element on each side of the equation. The table below
shows this information
Dipole interactions and hydrogen bonds will not affect bromine or mercury. Therefore, the
only Van der Waals forces affecting the boiling points of Br and Hg are dispersion forces. The
number of electrons in the atoms of each substance will determine how
4 As wood burns, it reacts with oxygen in the air. Therefore, preventing air from reaching the
burning wood will cut off the supply of oxygen for the reaction. Without oxygen, a combustion
reaction cannot occur, and the wood cannot burn.
First, write prel
First, write the preliminary chemical equation. Calcium carbonate is the reactant, and calcium
oxide and carbon dioxide are the products. Therefore, the preliminary chemical equation is
A quick check shows that this equation is
Aluminum and oxygen are the reactants, and aluminum oxide is the product. The preliminary
chemical equation for the reaction is shown below:
The reaction is unbalanced. Use coefficients to balance the equation, as shown below:
Count the number of atoms of each element on each side of the arrow. The table below shows
the numbers of atoms for the elements in the equation.
Table of Atoms in Reactants and Products
2. Both Dalton and Democritus envisioned atoms as tiny, indivisible particles. They both thought
that atoms were the smallest units of matter. However, Dalton's atomic theory also explained
how atoms react to form compounds, and it related elements and at
Two adjacent N atoms are triple bonded together. The left N atom has a pair of electrons to the
left. The right N atom has a pair of electrons to the right.
Brackets enclose an OH molecule with a negative sign up and to the right of the right bracket.
2The atom of bromine contains 35 protons, so its atomic number is 35. It contains 45
neutrons, so its mass number is 35+45=80. The atom of rhenium contains 75 protons, so its
atomic number is 75. It contains 111 neutrons, so its mass number is 75+111=186.
The first word in the compound name is dinitrogen. Its root is nitrogen and its prefix is
di, so each molecule contains two nitrogen atoms. The second word is tetraoxide. Its
root is ox and its prefix is tetra, so each molecule contains four oxygen atom
3. The nucleus contains positively charged protons and neutral neutrons. Because the neutrons
have no charge, they do not contribute to the overall charge of the nucleus. This leaves the
nucleus with a positive charge. The electrons outside the nucleus ba
. Sulfur is in the same group as oxygen, so it has the same number of valence electrons as
oxygen: six. Therefore, a molecule of H2S will have the same structure as a molecule of H2O
(water). The sulfur atom will share two electrons with each of the hydro
The elements in group 1A all have only one valence electron located in an s subshell. The
number of the period indicates the number of the valence subshell, so francium must be in group
1A, period 7.
The elements in group 2A all have two valence electro
Most metals are solid at room temperature and can easily be pounded into sheets, stretched
into wires, or bent into other shapes. These properties make them ideal for use in jewelry.
Of the elements on the list, only gallium lies to the left of the line
The first electron shell of an atom can hold up to two electrons, and the second electron
shell can hold up to eight electrons. A carbon atom has six electrons. Two of them will fill
the first, innermost electron shell. The remaining four will partly fi
Only nonmetals are gases at room temperature, and most nonmetals form negatively charged
ions when they react with other elements. Therefore, fluorine and chlorine are nonmetals.
Iodine, helium, and hydrogen are the only nonmetals in the list.
3. A graph of the data made in another program is shown below.
4. Although a graph shows the same data that are displayed in a data table, it shows them in a
more visual way. That is, a graph shows the data as an image, rather than as numbers. Most
5. Use conversion factors to convert Calories to calories, and calories to joules.
1,000 cal 4.186 J325 Cal = 1.36 106 J
1 Cal 1 cal
6. Use a conversion factor to solve this problem. Remember to use the correct number
of significant figures.
1 cal425.3 J
3. Carbon's atomic number is 6, so it has six electrons. The diagram below shows how
those electrons will fill the subshells:
4. Aluminum has atomic number 13, so a neutral aluminum atom must have 13 electrons.
Therefore, the electron configuration of a
2According to the electromagnetic spectrum shown in Example 2, gamma rays have more
energy than X rays do. Therefore, atom A emits lower-energy radiation than atom B does. Atom
A's emission therefore corresponds to a transition between energy levels that