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Musya8 [376]
3 years ago
5

The half-life of thorium-227 is 18.72 days. How many days are required for three-fourths of a given amount to decay?

Chemistry
1 answer:
Pie3 years ago
7 0
T½=18.72days
therefore t¾=18.72+½ of 18.72
we have 18.72+9.36=28.08days
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Elements in Group 18 are known
o-na [289]

Answer:

C the number and placement of the electrons

Explanation:

Elements react with one another because they want to achieve a full valence shell of electrons. The noble gases already have a full valence shell of electrons, so they are unlikely to react with other elements.

6 0
3 years ago
See the questions on the sheet
Sergio [31]

Answer:

Question 1. Nonpolar covalent

Question 2. The fluorine atom is able to attract the shared electrons more strongly than a hydrogen atom

Question 3. True

Explanation:

Question 1

First of all, oxygen is a molecular compound, as it consists of non-metal atoms only (oxygen). This means we wouldn't expect to have any ionic bonding in it, as it doesn't contain a metal ion. A molecular compound has covalent bonding.

Whenever a diatomic molecule contains the same two atoms bonded by a bond, we expect to have a non-polar bond. This is due to the fact that the two atoms are identical and have the same values of electronegativity, meaning the difference in their electronegativity values is 0 and we have no net polarity within the bond.

For a bond between two different atoms, the molecule would be polar, as one atom would have a greater electronegativity (electron withdrawing force) compared to the other atom.

Question 2

Based on the principles of polarity, whenever we have a diatomic molecule, it's only non-polar when the two atoms are the same. In case of HF, we have two different atoms: hydrogen and fluorine. Since the two atoms are not identical, the molecule would be polar overall, as fluorine is more electronegative than hydrogen. Simply speaking, it means that fluorine attracts the shared electrons within the H-F bond stronger than hydrogen does. This makes a difference in electronegativity values between H and F non-zero and an overall polar bond.

Question 3

We may recall the Coulombic force equation. It states that the attraction force is directly proportional to the charge and inversely proportional to the square of a distance between the two charges.

A bond formed between two atoms or ions is the closest distance the two species can approach each other. Intermolecular forces, in contrast, are the forces that atoms experience within a distance greater than the bond length. We may conclude that for a greater distance, the Coulombic force is lower and, hence, the strength of intermolecular forces are significantly lower compared to covalent or ionic bonds.

7 0
3 years ago
What mass of dinitrogen monoxide, N2O, contains the same number of molecules as 3.00 g of trichlorofluoromethane, CCl3F?
erica [24]

Answer:

0.9612 g

Explanation:

First we <u>calculate how many moles are there in 3.00 g of CCl₃F</u>, using its <em>molar mass</em>:

  • 3.00 g CCl₃F ÷ 137.37 g/mol = 0.0218 mol CCl₃F

Now, we need to calculate how many grams of N₂O would have that same number of molecules, or in other words, <em>the same amount of moles</em>.

Thus we <u>calculate how many grams would 0.0218 moles of N₂O weigh</u>, using the <em>molar mass of N₂O</em> :

  • 0.0218 mol N₂O * 44.013 g/mol = 0.9612 g N₂O
3 0
3 years ago
Please Help Me!
S_A_V [24]

Answer:

The answer to your question is      SO₂   +   3H₂    ⇒     H₂S   + 2H₂O

Explanation:

Reaction

                                SO₂   +   H₂    ⇒     H₂S   +  H₂O

                      Reactants           Elements            Products

                              1                   Sulfur                    1

                               2                  Hydrogen               4

                              2                   Oxygen                   1

This reaction is unbalanced so we need to balance it.

                              SO₂   +   3H₂    ⇒     H₂S   + 2H₂O

                      Reactants           Elements            Products

                              1                   Sulfur                   1

                              6                  Hydrogen               6

                              2                   Oxygen                  2

Now, the reaction is balanced

3 0
4 years ago
CHEM HELP!
sweet [91]

So let's convert this amount of mL to grams:

\frac{13.6g}{1mL}*1.2mL=16.32g

Then we need to convert to moles using the molar weight found on the periodic table for mercury (Hg):

\frac{1mole}{200.59g}*16.32g=8.135*10^{-2}mol

Then we need to convert moles to atoms using Avogadro's number:

\frac{6.022*10^{23}atoms}{1mole} *[8.135*10^{-2}mol]=4.90*10^{22}atoms

So now we know that in 1.2 mL of liquid mercury, there are 4.90*10^{22}atoms present.

4 0
4 years ago
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