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3 years ago

Magnesium reacts with Oxygen gas forming Magnesium oxide as shown;

1 answer:

5 0

Molar mass:

O2 = 16 x 2 = 32.0 g/mol Mg = 24 g/mol

<span>2 Mg(s) + O2(g) --->2 MgO(s)
</span>
2 x 24.0 g Mg -------------> 32 g O2
5.00 g Mg -----------------> ( mass of O2)

mass of O2 = 5.00 x 32 / 2 x 24.0

mass of O2 = 160 / 48

= 3.33 g of O2

hope this helps!

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Identify the electrophilic site in the following molecule, CH_3CH_2NHCH_2CH_3. (A) H (B) N (C) CH_2 (D) CH_3 (E) there is no ele

Serhud [2]

Answer:

Explanation:

An electrophile is an atom that loves electron. For an atom to be able to pull electrons closer to itself, it must be electron deficient and with a partial positive charge.

From the structure give, N is a highly electronegative atom and it is a nucleophile. This implies it loves the nucleus which is positively charged.

The Carbon atom attached to it is an electrophile because it has a lower electronegativity thereby leaving a partial positive charge on it. Therefore, the carbon will be attracted to the nucleophile.

4 0

3 years ago

What is the ph of a 0.10 m solution of ethylamine at 25 oc? the pkb of ethylamine at 25 ºc is 3.25. ethylamine is a weak base?

denis-greek [22]

To determine the pH of a weak base, we use the equation:

pH = 14 + 0.5 log Kb

Therefore,

pH = 14 + 0.5 log 3.25
pH = 14.26

A weak base is a base which does not fully dissociates into ions when in solution. The solution would contain cations, anions and the compound itself. Hope this helps.

5 0

3 years ago

If 175mL of oxygen is produced at STP, how many grams of hydrogen peroxide, H2O2

Vlad [161]

Answer:

0.53g

Explanation:

We'll begin by converting 175mL to L. This is illustrated below:

1000mL = 1L

Therefore 175mL = 175/1000 = 0.175L

Next, we shall calculate the number of mole of O2 that occupy 0.175L. This is illustrated below:

1 mole of O2 occupy 22.4L at stp.

Therefore, Xmol of O2 will occupy 0.175L i.e

Xmol of O2 = 0.175/22.4

Xmol of O2 = 7.81×10¯³ mole

Therefore, 7.81×10¯³ mole of O2 occupy 175mL.

Next, we shall determine the number of mole of H2O2 that decomposed to produce 7.81×10¯³ mole of O2. This is illustrated below:

2H2O2 —> 2H2O + O2

From the balanced equation above,

2 moles of H2O2 decomposed to produce 1 mole of O2.

Therefore, Xmol of H2O2 will decompose to produce 7.81×10¯³ mole of O2 i.e

Xmol of H2O2 = 2 x 7.81×10¯³

Xmol of H2O2 = 1.562×10¯² mole

Therefore, 1.562×10¯² mole of H2O2 decomposed in the reaction.

Finally, we shall convert 1.562×10¯² mole of H2O2 to grams. This is illustrated below:

Molar mass of H2O2 = (2x1) + (16x2) = 34g/mol

Mole of H2O2 = 1.562×10¯² mole

Mass of H2O2 =..?

Mole = mass /Molar mass

1.562×10¯² = mass /34

Cross multiply

Mass of H2O2 = 1.562×10¯² x 34

Mass of H2O2 = 0.53g

Therefore, 0.53g of Hydrogen peroxide, H2O2 were decomposition in the reaction.

3 0

3 years ago

Write the appropriate symbol for each of the following isotopes: (a) Z 74, A 186; (b) Z 80, A 201; (c) Z 34, A 76; (d) Z 94, A 2

beks73 [17]

Answer: a) $_{74}^{186}\textrm{W}$

b) $_{80}^{201}\textrm{Hg}$

c) $_{34}^{76}\textrm{Se}$

d) $_{94}^{239}\textrm{Pu}$

Explanation:

General representation of an element is given as:_Z^A\textrm{X}

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

In an atom, when neutrons or protons are lost or gains, it directly affects the mass number of an atom.

Atomic number is defined as the number of protons or number of electrons that are present in an atom.

It is characteristic of a particular element.

Atomic number = Number of electrons = Number of proton

a) Z 74, A 186: $_{74}^{186}\textrm{W}$

b) Z 80, A 201: $_{80}^{201}\textrm{Hg}$

c) Z 34, A 76: $_{34}^{76}\textrm{Se}$

d) Z 94, A 239.: $_{94}^{239}\textrm{Pu}$

6 0

3 years ago

The following equilibrium is formed when copper and bromide ions are placed in a solution:

JulsSmile [24]

Answer:

1. Reaction will shift rightwards towards the products.

2. It will turn green.

3. The solution will be cooler..

B) It will turn green.

Explanation:

Hello,

In this case, for the stated equilibrium:

$heat + Cu(H_2O)_6 ^{+2} (blue) + 4Br^- \rightleftharpoons 6H_2O + CuBr_4^{-2} (green)$

In such a way, by thinking out the Le Chatelier's principle, we can answer to each question:

1. If potassium bromide, which adds bromide ions, is added more reactant is being added to the solution, therefore, the reaction will shift rightwards towards the products.

2. The formation of the green complex is favored, therefore, it will turn green.

3. The solution will be cooler as heat is converted into "cold" in order to reestablish equilibrium.

B) In this case, as the heat is a reactant, if more heat is added, more products will be formed, which implies that it will turn green.

Regards.

3 0

3 years ago