1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Fed [463]
4 years ago
12

Why are the average atomic masses of some of the elements in parentheses?

Chemistry
1 answer:
Pie4 years ago
4 0
Because its only representing the most stable isotope of that element but its considered the atomic mass and not average atomic mass
You might be interested in
A chemist mixes oxygen gas and hydrogen gas to form water, which is composed of one oxygen and two hydrogen atoms per molecule.
Flauer [41]
<span>When a chemist mixes oxygen gas and hydrogen gas to form water, which is composed of one oxygen and two hydrogen atoms per molecule. The hydrogen and oxygen atoms bounds together by making a bond called covalent bond.<span> In a covalent bond, two atoms are bound together because they each want to "share" each other's electrons.</span></span>
6 0
4 years ago
Read 2 more answers
For the reaction shown, calculate how many grams of oxygen form when each quantity of reactant completely reacts.
Diano4ka-milaya [45]
The balanced chemical reaction is given as follows:

<span>2 KClO3(s) → 2 KCl(s) + 3 O2(g)

The starting amount of the reactant are given above. These values would be used for the calculations. We do as follows:

</span>2.72 g KClO3 (1 mol / 122.50g )( 3 mol O2 / 2 mol KClO3 ) ( 32 g O2 / 1 mol O2 ) = 1.06 g O2
<span>
0.361 g KClO3 </span>(1 mol / 122.50g )( 3 mol O2 / 2 mol KClO3 ) ( 32 g O2 / 1 mol O2 ) = 0.14 g O2
<span>
83.6 kg KClO3 (1000g / 1kg) </span>(1 mol / 122.50g )( 3 mol O2 / 2 mol KClO3 ) ( 32 g O2 / 1 mol O2 ) = 3275.76 g O2
<span>
22.5 mg KClO3</span> (1 g / 1000 mg) (1 mol / 122.50g )( 3 mol O2 / 2 mol KClO3 ) ( 32 g O2 / 1 mol O2 ) = 0.009 g O2
4 0
3 years ago
Read 2 more answers
When 21.45 g of KNO3 was dissolved in water in a calorimeter, the temperature fell from 25.00°C to 14.14 °C. If the heat capacit
pashok25 [27]

25.9 kJ/mol. (3 sig. fig. as in the heat capacity.)

<h3>Explanation</h3>

The process:

\text{KNO}_3\;(s) \to \text{KNO}_3\;(aq).

How many moles of this process?

Relative atomic mass from a modern periodic table:

  • K: 39.098;
  • N: 14.007;
  • O: 15.999.

Molar mass of \text{KNO}_3:

M(\text{KNO}_3) = 39.098 + 14.007 + 3\times 15.999 = 101.102\;\text{g}\cdot\text{mol}^{-1}.

Number of moles of the process = Number of moles of \text{KNO}_3 dissolved:

\displaystyle n = \frac{m}{M} = \frac{21.45}{101.102} = 0.212162\;\text{mol}.

What's the enthalpy change of this process?

Q = C\cdot \Delta T = 0.505 \times (25.00 - 14.14) = 5.4843\;\text{kJ} for 0.212162\;\text{mol}. By convention, the enthalpy change \Delta H measures the energy change for each mole of a process.

\displaystyle \Delta H = \frac{Q}{n} = \frac{5.4843\text{kJ}}{0.212162\;\text{mol}} = 25.8\;\text{kJ}\cdot\text{mol}^{-1}.

The heat capacity is the least accurate number in these calculation. It comes with three significant figures. As a result, round the final result to three significant figures. However, make sure you keep at least one additional figure to minimize the risk of rounding errors during the calculation.

4 0
3 years ago
Please help! (no links)
Rus_ich [418]
It's D because I know bcz I'm smart 8 times 8 is 60-nart
5 0
3 years ago
Calculate the mass of sucrose needed to prepare a 2000 grams of 2.5% sucrose solution.
meriva

Answer:

50 g Sucrose

Explanation:

Step 1: Given data

  • Mass of solution: 2000 g
  • Concentration of the solution: 2.5%

Step 2: Calculate the mass of sucrose needed to prepare the solution

The concentration of the solution is 2.5%, that is, there are 2.5 g of sucrose (solute) every 100 g of solution. The mass of sucrose needed to prepare 2000 g of solution is:

2000 g Solution × 2.5 g Sucrose/100 g Solution = 50 g Sucrose

5 0
3 years ago
Other questions:
  • Match each alkane names and structures.
    8·1 answer
  • A storm that get its energy from warm humbid air at the ocean surface is called a
    7·1 answer
  • One brand of extra-strength antacid tablets contains 750 mg of calcium carbonate (100 g/mol) in each tablet. Stomach acid is ess
    12·1 answer
  • Under which conditions of temperature and pressure does carbon dioxide gas behave most like an ideal gas?
    12·2 answers
  • Dalton's Law of Partial pressure: The total pressure of a gas mixture is the sum of the partial pressures of each gas . Therefor
    5·2 answers
  • What is the net ionic charge of calcium ion
    12·1 answer
  • Write the Ground state electron configuration of Ca using the noble-gas shorthand notation
    12·1 answer
  • Methane gas is collected over water at 25 C and an atmospheric pressure of 775 mmHg. What is the dry pressure of the gas at this
    13·1 answer
  • Give two similarities in the products when chlorine, bromine and iodine react with iron
    14·1 answer
  • What minimum temperature is needed to dissolve 60 grams of NH4Cl in 100 g H2O?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!