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Kisachek [45]
3 years ago
13

Determine the average atomic mass of helium, which has two isotopes having atomic masses 4.0026 amu and 3.0160 amu. The relative

abundance of the two isotopes is 99.9999 percent and 0.0001 percent, respectively.
Chemistry
1 answer:
7nadin3 [17]3 years ago
8 0
m_a=4.0026 \cdot 99.9999 \% + 3.0160 \cdot 0.0001 \%= \\ =4.0025959974+0.000003016= \\
=4,0025990134 \ [amu]

The average atomic mass of helium is 4,0025990134 amu.
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Given the following acids and their Ka values: Phenol, C6H5OH Ka = 1.00 × 10-10 Acetic acid, CH3CO2H Ka = 1.80 × 10-5 Nitrous ac
Ierofanga [76]

Answer:

NO_2^- < CH_3COO^- < C_6H_5O^-

Explanation:

K_a value is a measure of acidic strength. The larger the K_a value, the stronger is the acid and the weaker is the conjugate base.

The given K_a values are as follows -

Phenol = 1\times 10^-^1^0

Acetic acid = 1.80 \times 10^-^5

Nitrous acid = 4.50 \times 10^-^4

Order of increasing acid strength will be -

Phenol < Acetic acid < Nitrous acid

Strongest acid will have weakest conjugate base so the order of increasing base strength will be -

NO_2^- < CH_3COO^- < C_6H_5O^-

4 0
4 years ago
5. A hollow glass sphere has a volume of 350 mL and
Rina8888 [55]

Explanation:

Given that,

Volume of a hallow glass sphere is 350 mL

Specific gravity is 1.252

We need to find the weight of the sphere. The ratio of density of substance to the density of water is called specific gravity.

The density of water is 1 g/mL

\text{specific gravity}=\dfrac{\text{density of substance}}{\text{density of water}}\\\\SG=\dfrac{m}{V\times \rho_w}\\\\m=SG\times V\times \rho_w\\\\m=1.252\times 350\ mL\times 1\ g/mL\\\\m=438.2\ \text{grams}

We know that,

1 pound = 453.592 grams

So,

m = 0.97 lbs

So, the weight of the sphere is 0.97 lbs or 0.97 pounds.

5 0
4 years ago
Need help please I need to select one element for each following families on the periodic table
Aleksandr-060686 [28]

There are five Family on the periodic table that are alkali metals , Alkaline earth metals , transition metals , Halogens family and noble gas family.

1) In alkali metals, there are six elements are present and among all the elements Sodium metal should be selected. Because sodium metal is most abundant metal in the world.

  • uses of sodium are
  • sodium salt are common salt that added to the food to enhance the taste.
  • washing soda are made up of sodium salt which is used as water softener.
  • sodium salts are also used as buffer to maintain Ph.

2) In alkaline earth metal family, The magnesium element should be selected.

  • uses of magnesium are
  • since magnesium is a soft metal so it can burn easily therefore it is used in fire works.
  • magnesium is also important for proper growth and maintenance of bones.
  • Magnesium is light weight metal so it can used to make car seat , luggage and power tools etc.

3) In Halogens gas family , chlorine should be selected.

  • Uses of chlorine are
  • The chlorine is used in cleaning purpose as it act as bleaching agent.
  • Chlorine is also used to prepare the pesticides to removes pest in crops.
  • In refrigerators, the cold breeze is coming out is chlorine gas which are used to increase the shelf life of the plants.

4) In transition metals , copper metal should be choose.

  • Use of copper metal are
  • Copper is highly ductile metal so it drawn into wires and used in various electrical purpose.
  • The copper has anti corrosive properties so it can used in making kitchen utensils.
  • The copper has anti microbial property so it can used in packaging of food.

5) In noble gas elements, The helium gas should be selected

  • uses of helium gas are
  • It used as semiconductors.
  • It used in party balloons.
  • The helium is inert gas so it used to make optical fibers.

These are the daily life usage of all the elements of each family of the periodic table.

Lean more about Periodic Table here

brainly.com/question/15987580

#SPJ9

3 0
1 year ago
The decomposition of water into hydrogen gas H2 and oxygen gas 02 can be modeled by the balanced chemical equation
ivolga24 [154]

Answer:

2H20 ------> 2H2 + O2

4 0
4 years ago
Consider the diagram of the Earth, Sun, and Moon system. Which phenomenon is MOST DIRECTLY caused by the revolution of the Earth
zlopas [31]
It is commonly known that our Galaxy rotates upon the sun because of gravity. The diagrams' arrows sort of describe it. Id suggest Gravity as the answer.

5 0
3 years ago
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