The atomic mass of a carbon isotope that has 6 protons and 7 neutrons is<u> </u><u>13</u>
Explanation:
Remember that whilst the atomic number represents the number of protons in an atom, the mass number represents the summation of protons and neutrons particles in the atomic nuclei. Therefore, in this case, the carbon will have a mass number of;
6 + 7 = 13
Isotopes of an element usually have the same atomic number but different mass numbers -because they have slightly different numbers of neutrons. An example is isotopes of Carbon; C-14 and C-12
Even though the numbers are in scientific notation, they are still just numbers. Essentially the question is as simple as "An apple weighs an ounce, how much do 35 apples weigh?". So all you have to do is multiply.
3.25 x

x 6.0 x

= 195
<u>Answer:</u> The mass percent of lead in lead (IV) carbonate is 63.32 %
<u>Explanation:</u>
The given chemical formula of lead (IV) carbonate is 
To calculate the mass percentage of lead in lead (IV) carbonate, we use the equation:

Mass of lead = (1 × 207.2) = 207.2 g
Mass of lead (IV) carbonate = [(1 × 207.2) + (2 × 12) + (6 × 16)] = 327.2 g
Putting values in above equation, we get:

Hence, the mass percent of lead in lead (IV) carbonate is 63.32 %
Answer:
A sample of a gas (5.0 mol) at 1.0 atm is expanded at constant temperature from 10 L to 15 L. The final pressure is 0.67 atm.
Step by Step Explanation?
Boyle's law states that in constant temperature the variation volume of gas is inversely proportional to the applied pressure.
The formula is,
P₁ x V₁ = P₂ × V₂
Where,
P₁ is initial pressure = 1 atm
P2 is final pressure = ? (Not Known)
V₁ is initial volume = 10 L
V₂ is final volume = 15 L
Now put the values in the formula,
\begin{gathered}\rm 1\times 10 = P_2\times 15\\\\\rm P_2 = \frac{10}{15\\} \\\\\rm P_2 = 0.67\end{gathered]
Therefore, the answer is 0.67 atm.