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2 years ago

How metals have been used thorough the ages PLS

1 answer:

8 0

1751 - Nickel
1774 - Manganese
1781 - Molybdenum
1782 - Tellurium
1783 - Tungsten
1789 - Uranium
1789 - Zirconium
1791 - Titanium
1794 - Yttrium
1797 - Berylium
1797 - Chromium
1801 - Niobium
1802 - Tantalum
1803 - Iridium, Palladium, Rhodium
1807 - Potassium, Sodium
1808 - Boron, Barium, Calcium, Magnesium, Strontium
1814 - Cerium
1817 - Lithium, Cadmium, Selenium
1823 - Silicon
1827 - Aluminium
1828 - Thorium
1830 - Vanadium
1839 - Lanthanum
1843 - Erbium, Terbium
1844 - Ruthenium
1860 - Cesium, Rubidium
1861 - Thallium
1863 - Indium
1875 - Gallium
1878-1885 - Holmium, Thulium, Scandium, Samarium, Gadalinium, Praseodynium, Neodynium, Dysprosium
1886 - Germanium
1898 - Polonium, Radium
1899 - Actinium
1901 - Europium
1907 - Lutetium
1917 - Protactinium
1923 - Hafnium
1924 - Rhenium
1937 - Technetium
1939 - Francium
1945 - Promethium
1940-61 - Transuranium elements – (Neptunium, Plutonium, Curium, Americum, Berkelium, Californium, Einsteinium, Fermium, Mendelevium, Nobelium, Lawrencium)

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A solution contains 15.27 grams of NaCl in 0.670 kg water at 25 °C. What is the vapor pressure of the solution?

Anvisha [2.4K]

Answer:

The vapor pressure of the solution is 23.636 torr

Explanation:

$P_{solution} = X_{solvent}*P_{solvent}$

Where;

$P_{solution$ is the vapor pressure of the solution

$X_{solvent$ is the mole fraction of the solvent

$P_{solvent$ is the vapor pressure of the pure solvent

Thus,

15.27 g of NaCl = [(15.27)/(58.5)]moles = 0.261 moles of NaCl

0.67 kg of water = [(0.67*1000)/(18)]moles = 37.222 moles of H₂O

Mole fraction of solvent (water) = (number of moles of water)/(total number of moles present in solution)

Mole fraction of solvent (water) = (37.222)/(37.222+0.261)

Mole fraction of solvent (water) = 0.993

Note: the vapor pressure of water at 25°C is 0.0313 atm

Therefore, the vapor pressure of the solution = 0.993 * 0.0313 atm

the vapor pressure of the solution = 0.0311 atm = 23.636 torr

5 0

3 years ago

Read 2 more answers

Dinitrogen tetraoxide and nitrogen dioxide are two gases that exist in equilibrium at a range of temperatures. NO2 is a reddish

Vilka [71]

Answer:

1-C

2-A

3-B

Explanation:

K=[N204]/[NO2]

In the first question the reaction is at equilibrium. When the temperature is decreased, more N2O4 if formed and K increases. When the temperature is increased, more NO2 is formed and K decreases.

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3 years ago

What is carbon? What does it do?

Archy [21]

Answer:

Carbon is in carbon dioxide, which is a greenhouse gas that works to trap heat close to Earth. Carbon is the chemical backbone of life on Earth. Carbon compounds regulate the Earth's temperature, make up the food that sustains us, and provide energy that fuels our global economy. Most of Earth's carbon is stored in rocks and sediments. The rest is located in the ocean, atmosphere, and in living organisms

Explanation:

Hope it helps. Can you give me BRAINLIEST ANSWER. Thank you

7 0

2 years ago

Mantle convection is a process of that creates circular currents in the asthenosphere. As a result, the plates slowly move.

LUCKY_DIMON [66]

Answer:

Rigid plates that move around Earth's surface is called tectonic plates. 

Explanation:

Lithosphere is rigid and relatively cold and is the outer surface of the planet. The convective motions of maintenance break the lithosphere into plates.

This place that a form can move in any direction, can move towards each other, can move away and push each other which is the reason for formation of mountains for shifting of continents for making of ocean basin.

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3 years ago

A sample of juice has a pH of 4.2. Whsat is the concentration in mol/dm3 of OH in the juice?

Annette [7]

Answer:

6 * 10^-4M

Explanation:

use this equation

[ H + ] = 10 − pH

6 0

2 years ago