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Lana71 [14]
2 years ago
7

How metals have been used thorough the ages PLS

Chemistry
1 answer:
Ilya [14]2 years ago
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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Draw a line-bond structure for CBrN. Explicitly draw all H atoms. You do not have to include lone pairs in your answer. In cases
DochEvi [55]

Answer:

Br - C ≡ N

Explanation:

To draw the Lewis line-bond structure we need to bear in mind the octet rule, which states that in order to gain stability each <em>atom tends to share electrons until it has 8 electrons in its valence shell</em>.

  • C has 4 e⁻ in its valence shell so it will form 4 covalent bonds.
  • Br has 7 e⁻ in its valence shell so it will form 1 covalent bond.
  • N has 5 e⁻ in its valence shell so it will form 3 covalent bonds.

The most stable structure that respects these premises is:

Br - C ≡ N

It does not have any H atom.

8 0
2 years ago
A 35.0 ml sample of 0.225 m hbr was titrated with 42.3 ml of koh. What is the concentration of the koh?
Lemur [1.5K]

Answer:

The concentration of KOH is 0.186 M

Explanation:

First things first, we need too write out the balanced equation between HBr and KOH.

This is given as;

KOH (aq) + HBr (aq) → KBr (aq) + H2O (l)

From the reaction above, we can tell that it takes 1 mole of KOH to react with 1 mole of HBr.

We use the acid base formular in calculating unknown concentrations. This is given as;

\frac{CaVa}{CbVb}  = \frac{na}{nb}

where;

Ca = Concentration of acid

Va = Volume of acid

Cb = Concentration of base

Vb = Volume of base

na = Number of moles of acid

nb = Number of moles of base

KOH is the base and HBr is acid.

Hence;

Ca = 0.225

Va = 35

Cb = ?

Vb = 42.3

na = 1

nb = 1

Making Cb subject of formular we have;

Cb = \frac{CaVaNb}{VbNa}

Cb = (0.225 * 35 * 1) / (42.3 * 1)

Cb = 0.186 M

5 0
3 years ago
For a particular reaction, Δ=−111.4 kJ and Δ=−25.0 J/K.
vichka [17]

Answer:

\Delta G =-103.95kJ

Explanation:

Hello there!

In this case, since the thermodynamic definition of the Gibbs free energy for a change process is:

\Delta G =\Delta H-T\Delta S

It is possible to plug in the given H, T and S with consistent units, to obtain the correct G as shown below:

\Delta G =-111.4kJ-(298K)(-25.0\frac{J}{K}*\frac{1kJ}{1000J} )\\\\\Delta G =-103.95kJ

Best regards!

6 0
3 years ago
Suppose you could watch radioactive atoms decay. It would probably get quite boring as time went by. Why?
kari74 [83]

Answer: the answer should and most definitely be D.

Explanation: I mean think about it after a while only a few radioactive nuclei are left which means it will dye down after a while which also makes it very boring hope this helps :)

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3 years ago
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Coca cola is similar to tomato juice because
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B.) Because they both are Acids

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