The half-life of sodium-24 is equal 14,959 hours.
Answer:
0.89
Explanation:
You are mixing an acid and a base, so there will be a neutralization reaction.
One of the reactants will be in excess, so we must determine its concentration and then calculate the pH.
<em>Moles of NaOH
</em>
Moles of NaOH = 25 × 0.173
Moles of NaOH = 4.32 mmol
===============
<em>Moles of HCl
</em>
Moles of HCl = 35 × 0.342
Moles of HCl = 12.0 mmol
===============
<em>Amount of excess reactant
</em>
NaOH + HCl ⟶ NaCl +H₂O
<em>n</em>/mmol: 4.32 12.0
The 4.32 mmol of NaOH reacts completely with 4.32 mmol of HCl.
Excess HCl = 12.0 – 4.32
Excess HCl = 7.6 mmol
===============
<em>Concentration of the excess HCl
</em>
Total volume = 25 + 35
Total volume = 60 mL
<em>c </em>= millimoles HCl/millilitres HCl
<em>c</em> = 7.6/60
<em>c</em> = 0.13 mol/L
===============
<em>Calculate the pH
</em>
The HCl dissociates completely to hydronium ions, so
[H₃O⁺] = 0.13 mol·L⁻¹
pH = -log[H₃O⁺]
pH = -log0.13
pH = 0.89
Answer:
1. It dissolves much more ice faster than sodium chloride
2. Calcium chloride is more effective in melting ice at lower temperatures.
Explanation:
Salts are used to melt ice on roadways and sidewalks because they help to lower the freezing point of water.
Sodium chloride and calcium chloride are both salts used for this purpose but calcium chloride is usually preferred for the following two reasons:
1. It dissolves much more ice faster than sodium chloride: Calcium chloride dissolves much more ice faster than sodium chloride because when it dissociates, it produces three ions instead of the two produced when sodium chloride. Therefore, the heat of hydration of its ions is greater than that of sodium chloride.
2. Calcium chloride is more effective in melting ice at lower temperatures. It lowers the freezing point of water more than sodium chloride. Calcium chloride is able to lower the freezing point of water to about -52°C while sodium chloride only lowers it to about -6°C.
Answer:
C the mass of the reactant molecules is the same as the mass of the product
Using the given formula, the density of the material is 2.015 g/mL
<h3>Calculating Density </h3>
From the question, we are to determine the density of the material
From the given formula
Density = Mass / Volume
And from the given information,
Mass = 65.5 g
and volume = 32.5 mL
Putting the parameters into the equation,
Density = 65.5/32.5
Density = 2.015 g/mL
Hence, the density of the material is 2.015 g/mL.
Learn more on Calculating density here: brainly.com/question/24772401
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