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3 years ago

100 points! Report on an element

Chemistry

2 answers:

AnnyKZ [126]3 years ago

7 0

Gold.

Atomic mass 196.96...

Metal

Anglo Saxon

Group number 11

Golf is used for money or jewelry

It is natural found in caves

Gold is valuable and beautiful

Hope this helps!

Luden [163]3 years ago

6 0

Hydrogen H weight: 81

Non-metal

Hydrogen is the simplest element; an atom consists of only one proton and one electron. It is also the most plentiful element in the universe. Despite its simplicity and abundance, hydrogen doesn't occur naturally as a gas on the Earth--it is always combined with other elements.

period 1 group 1

Hydrogen is easily the most abundant element in the universe. It is found in the sun and most of the stars, and the planet Jupiter is composed mostly of hydrogen. On Earth, hydrogen is found in the greatest quantities as water.

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The oxidation number of magnesium in magnesium chloride is _____.

LenaWriter [7]

I hope this would be able to help u
dont forget the symbol its +2

3 0

3 years ago

Can someone please help me on #17? I don’t get it :(

Dmitry [639]

Given is the specific heat of water equal to 4.18 Joule per gram per *C.

This means to raise the temperature of 1 g of water by 1 degree Celsius we need 4.18 joule of energy.

Now, look at the question. We are asked that how much amount of energy would be required to raise the temperature of 25 g of water by (54-50) = 4 degree celsius.

To do so we have formula

Q = m C (temperature difference)

Have a look at pic for answer

5 0

3 years ago

The standard enthalpy of formation (ΔHf°) of calcium carbonate is –1207 kJ/mol. Which ONE of the equations below has ΔH° = –1207

Art [367]

Answer:

A) Ca(s) + C(s) + 3/2 O₂(g) → CaCO₃(s)

Explanation:

Standard enthalpy of formation of a chemical is defined as the change in enthalpy durin the formation of 1 mole of the substance from its constituent elements in their standard states.

The consituent elements of calcium carbonate, CaCO₃, in their standard states (States you will find this pure elements in nature), are:

Ca(s), C(s) and O₂(g)

That means, the equation that represents standard enthalpy of CaCO₃ is:

<em>Is the equation that has ΔH° = -1207kJ/mol</em>

3 0

3 years ago

0.10 M potassium chromate is slowly added to a solution containing 0.20 M AgNO3 and 0.20 M Ba(NO3)2. What is the Ag+ concentrati

erastova [34]

Answer:

$[Ag^{+}]=4.2\times 10^{-2}M$

Explanation:

Given:

[AgNO3] = 0.20 M

Ba(NO3)2 = 0.20 M

[K2CrO4] = 0.10 M

Ksp of Ag2CrO4 = 1.1 x 10^-12

Ksp of BaCrO4 = 1.1 x 10^-10

$BaCrO_4 (s)\leftrightharpoons Ba^{2+}(aq)\;+\;CrO_{4}^{2-}(aq)$

$Ksp=[Ba^{2+}][CrO_{4}^{2-}]$

$1.2\times 10^{-10}=(0.20)[CrO_{4}^{2-}]$

$[CrO_{4}^{2-}]=\frac{1.2\times 10^{-10}}{(0.20)}= 6.0\times 10^{-10}$

Now,

$Ag_{2}CrO_4(s) \leftrightharpoons 2Ag^{+}(aq)\;+\;CrO_{4}^{2-}(aq)$

$Ksp=[Ag^{+}]^{2}[CrO_{4}^{2-}]$

$1.1\times 10^{-12}=[Ag^{+}]^{2}](6.0\times 10^{-10})$

$[Ag^{+}]^{2}]=\frac{1.1\times 10^{-12}}{(6.0\times 10^{-10})}= 1.8\times 10^{-3}$

$[Ag^{+}]=\sqrt{1.8\times 10^{-3}}=4.2\times 10^{-2}M$

So, BaCrO4 will start precipitating when [Ag+] is 4.2 x 1.2^-2 M

7 0

3 years ago

Wich are the disadvantages of skimming oil spills?

sweet-ann [11.9K]

Oil is sucked up through wide floating heads and pumped into storage tanks. Although suction skimmers are generally very efficient, one disadvantage is that they are vulnerable to becoming clogged by debris and ice and require constant skilled observation.

4 0

3 years ago