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3 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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Which is the best example of a new substance forming?

Hunter-Best [27]

Answer:

lighting a match is the answer.

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3 years ago

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I really need an answer by tonight!

Anton [14]

The water cycle iss a process which helps to circulate and replenish water on earth.

<h3>What is hydrology?</h3>

Hydrology is the scientific study of water bodies , the changes that occur in them as well as the various features and behavior of water bodies such as oceans and rivers.

Water circulation created by prevailing wind systems. The Gulf Stream is an example up of the Coriolis effect.

The length of open sea over which wind can blow steadily to create waves is called fetch.

Salinity is the amount of dissolved salt in a liquid

The distance from the crest of one wave to the crest of another is called wavelength

Water circulation created by differences in density deepwater currents

Energy is what moves forward and through a wave.

The cyclical process of the changing state and movement of water around the Earth through evaporation, condensation, and precipitation is called water cycle.

As the amount of salt in water increases, the density of the water increases.

The type of energy possessed by moving water is called kinetic energy.

The rising of ocean water bringing nutrients up from the deep us called upwelling.

Therefore, the water cycle helps to circulate and replenish water on earth.

Learn more about water cycle at: brainly.com/question/2164391

5 0

2 years ago

What is the difference between the number of electrons in an atom of selenium,Se, and the number of electrons in an atom of alum

aliina [53]

Answer:

A)21

Explanation:

To know the difference between the number of electrons in the two atoms, we must first know the number of electrons in the atoms.

For Selenium, Se, we have 34 electrons. The element is in group 6 on the periodic table.

Aluminum on the other hand is in the Boron family with a total of 13 electrons.

The difference,( 34-13) electrons gives a total of 21 electrons

5 0

3 years ago

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Iron has a density of 7.86 g/cm3. Calculate the volume (in dL) of a piece of iron having a mass of 4.07 kg . Note that the densi

elena-s [515]

Answer:

The volume of the piece of iron is 5.18dL.

Explanation:

The density (ρ) is equal to the mass (m) divided the volume (V).

$\rho = \frac{m}{V}$

If we rearrange it, we have:

$V=\frac{m}{\rho }$

To express the volume in dL we will need the following relations:

1 dL = 0.1 L
1 kg = 10³ g
1 cm³ = 1 mL
1mL = 10⁻³L

Then,

$\rho = \frac{7.86g}{cm^{3} } .\frac{1cm^{3} }{1mL} .\frac{1mL}{10^{-3}L } .\frac{1kg}{10^{3}g } =7.86kg/L$

Finally,

$V=\frac{m}{\rho }=\frac{4.07kg}{7.86 kg/L} =0.518L.\frac{1dL}{0.1L} =5.18dL$

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3 years ago

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How many moles of lead, Pb, are in 1.50 x 10^12 atoms of lead?

gulaghasi [49]

<h3>Answer:</h3>

2.49 × 10⁻¹² moles Pb

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

<u>Chemistry</u>

<u>Atomic Structure</u>

Using Dimensional Analysis
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<h3>Explanation:</h3>

<u>Step 1: Define</u>

1.50 × 10¹² atoms Pb

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

Set up: $\displaystyle 1.50 \cdot 10^{12} \ atoms \ Pb(\frac{1 \ mol \ Pb}{6.022 \cdot 10^{23} \ atoms \ Pb})$
Multiply: $\displaystyle 2.49087 \cdot 10^{-12} \ moles \ Pb$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 3 sig figs.</em>

2.49087 × 10⁻¹² moles Pb ≈ 2.49 × 10⁻¹² moles Pb

5 0

3 years ago