All categories

3 years ago

6. Why are the atomic masses of elements usually decimal numbers?

1 answer:

3 0

The atomic mass of elements are usually decimals as it makes the atomic masses more accurate and exact. The mass of an atom is also the weighted average of the elements known isotopes and since it’s the average, the number is most likely going to be a decimal number.

I hope this helps :)

You might be interested in

Question 2 of 50

wolverine [178]

The thermal decomposition of calcium carbonate will produce 14 g of calcium oxide. The stoichiometric ratio of calcium carbonate to calcium oxide is 1:1, therefore the number of moles of calcium carbonate decomposed is equal to the number of moles of calcium oxide formed.

Further Explanation:

To solve this problem, follow the steps below:

Write the balanced chemical equation for the given reaction.
Convert the mass of calcium carbonate into moles.
Determine the number of moles of calcium oxide formed by using the stoichiometric ratio for calcium oxide and calcium carbonate based on the coefficient of the chemical equation.
Convert the number of moles of calcium oxide into mass.

Solving the given problem using the steps above:

STEP 1: The balanced chemical equation for the given reaction is:

$CaCO_{3} \rightarrow \ CaO \ + \ CO_{2}$

STEP 2: Convert the mass of calcium carbonate into moles using the molar mass of calcium carbonate.

$mol \ CaCO_{3} \ = 25 \ g \ CaCO_{3} \ (\frac{1 \ mol \ CaCO_{3}}{100.0869 \ g \ CaCO_{3}})\\ \\\boxed {mol \ CaCO_{3} \ = 0.2498 \ mol}$

STEP 3: Use the stoichiometric ratio to determine the number of moles of CaO formed.

For every mole of calcium carbonate decomposed, one more of a calcium oxide is formed. Therefore,

$mol \ CaO \ = 0.2498 \ mol$

STEP 4: Convert the moles of CaO into mass of CaO using its molar mass.

$mass \ CaO \ = 0.2498 \ mol \ CaO \ (\frac{56.0774 \ g \ CaO}{1 \ mol \ CaO})\\ \\mass \ CaO \ = 14.008 \ g$

Since there are only 2 significant figures in the given, the final answer must have the same number of significant figures.

Therefore,

$\boxed {mass \ CaO \ = 14 \ g}$

Learn More

Learn more about stoichiometry brainly.com/question/12979299
Learn more about mole conversion brainly.com/question/12972204
Learn more about limiting reactants brainly.com/question/12979491

Keywords: thermal decomposition, stoichiometry

5 0

3 years ago

Thirty grams of lead oxide and fifteen grams of ammonia react completely to produce solid lead, nitrogen gas, and liquid water.

Kitty [74]

45 g Thirty grams of lead oxide and fifteen grams of ammonia react completely to produce solid lead, nitrogen gas, and liquid water.

8 0

4 years ago

Read 2 more answers

Describe how you could use two LB/agar plates, some E. coli, and some ampicillin to determine how E. coli cells are affected by

KiRa [710]

Answer:

For this experiment we are going to take plate 1 as the control plate, so, in it there will be just E. coli in LB/agar; in plate 2, we are going to put E. coli in LB/agar and some ampicillin. Then, we have to wait for the E. coli colonies to form. After a while, the E. coli growth can be compared on both plates and determine if ampicillin affects or not the E. coli colonies.

Explanation:

If the ampicillin affects negatively E. coli colonies, we are going to observe that in plate 1 (control plate) there are E. coli colonies growing, but in plate 2, there is no E. coli colonies or, at least, there is a fewer number of colonies on it. If ampicillin doesn't affect E.coli, plate 1 (control) and plate 2 (ampicillin experiment) are going to be similar in number of colonies.

8 0

3 years ago

The elements cu, o, la, y, ba, tl, and bi are all found in high-temperature ceramic superconductors. write the expected electron

timama [110]

Part 1)
Cu- [Ar] 3d¹⁰4s¹ atomic number: 29

O- [He] 2s2 2p4 atomic number:8

La- [Xe] 5d¹ 6s² atomic number:57

Y- [Kr] 4d¹5s² atomic number:39

Ba- [Xe] 6s² atomic number:56

Tl- [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹ atomic number:81

Bi- [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³ atomic number:83

Part 2)
You are able to this by consulting the periodic table and following this steps:
-Find your atom's atomic number;
-Determine the charge of the atom (these were all uncharged)
-Memorize the order of orbitals (s, d, p, d.. and how many electrons they can fit)
-Fill in the orbitals according to the number of electrons in the atom
- for long electron configurations, abbreviate with the noble gases

4 0

3 years ago

Scientists examine fossils from three different animals. They determine that all three animals share similar structures and

mezya [45]

Answer:

C,B,A

Explanation:

C has the most similar structure

B has the second most similar structure

A has the least similair structure

6 0

3 years ago