The reason why some water and heat are added after Mg ribbon is reacted completely with air is to remove Mg3N2 as MgO.
Combustion reaction is a reaction in which a substance is completely burnt in oxygen. Magnesium ribbon can be converted to magnesium oxide by combustion in air.
The reaction is as follows; 2Mg(s) + O2 ----> 2MgO(s)
Since air contains nitrogen, Mg3N2 is also formed. Heat and water can be added to the reaction thereby converting magnesium nitride to magnesium oxide.
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True, it is formed from immense weathering over time. Hope it helped!
Answer:
147 g
Explanation:
<em>The number of moles of a substance is the ratio of the mass of the substance and the molar mass of that substance.</em> Mathematically,
mole = mass of substance/molar mass
In this case, Nick needs 3.5 moles of NaF, the molar mass of NaF is calculated as:
23 + 19 = 42 g/mol (Note: Na = 23, F = 19)
Hence,
mass of 3.5 mole NaF = mole x molar mass
= 3.5 x 42 = 147 g.
<em>Hence, Nick would need to measure out </em><em>147 g</em><em> NaF using a suitable weighing balance.</em>
Answer:
b) pH = 9.25
Explanation:
- NH4+(aq) + H2O(l) ↔ NH3(aq) + H3O+(aq)
- NH3 + H2O ↔ NH4+ + OH-
- 2 H2O ↔ H3O+ + OH-
⇒ Kb = [ NH4+ ] * [ OH- ] / [ NH3 ] = 1.86 E-5......from literature
mass balance NH4+:
⇒ M NH4+ = [ NH4+ ] - [ OH- ]
∴ [ NH3 ] ≅ M NH4+ = 0.26 M
⇒ Kb = (( 0.26 + [ OH- ] )) * [ OH- ] / 0.26 = 1.86 E-5
⇒ 0.26 [ OH-] + [ OH- ]² = 4.836 E-6
⇒ [ OH- ]² + 0.26 [ OH- ] - 4.836 E-6 = 0
⇒ [ OH- ] = 1.859 E-5 M
⇒ pOH = - Log ( 1.859 E-5 )
⇒ pOH = 4.7305
⇒ pH = 14 - pOH = 9.269
Answer:
O.1M
Explanation:
First let's generate a balanced equation for the reaction
NaOH + HCl —>NaCl + H2O
From the equation,
The ratio of the acid to base is 1:1.
From the question, we obtained the following:
Ma = Molarity of acid = 0.12M
Va = volume of acid = 21.35cm3
Vb = volume of base = 25.55cm3
Mb = Molarity of base =?
We obtained nA(mole of acid) and nB(mole of base) to be 1
The molarity of the base can be calculated for using:
MaVa/ MbVb = nA / nB
0.12x21.35 / Mb x 25.55 = 1
Cross multiply to express in linear form
Mb x 25.55 = 0.12x21.35
Divide both side by 25.55
Mb = (0.12x21.35) / 25.55
Mb = 0.1M
The molarity of the base is 0.1M
