Black holes….. universe……. radiation……. time
Answer:
2.7×10⁻³ mole
Explanation:
Applying
Q = it.............. Equation 1
Where Q = amount of charge, i = current, t = time
From the question,
Given: i = 0.860 A, t = 5 minutes = (5×60) seconds = 300 seconds
Subsitute these values into equation 1
Q = (0.860×300)
Q = 258 C
If one mole of electron has a charge of 96500 C
Then, x mole of electron will have a charge of 258 C
1 mole ⇒ 96500 C
X moles ⇒ 258 C
Solve for X
X = (258×1)/96500
X = 2.7×10⁻³ mole
97.22 grams of magnesium is needed.
<u>Explanation:</u>
The molar ratio of Mg to O2 to make MgO is 2:1
Here, we have 2 moles of O2, therefore we need 4 moles of Mg.
1 mol of Mg = 24.305 g
Therefore
4 moles of Mg = 4 
24.305 g
= 97.22 g
Hence we need 97.22grams of magnesium are needed to completely reactwith 2.00 mol of O2 in the synthesis reaction that producesmagnesium oxide.
<em>c</em> = 1.14 mol/L; <em>b</em> = 1.03 mol/kg
<em>Molar concentration
</em>
Assume you have 1 L solution.
Mass of solution = 1000 mL solution × (1.19 g solution/1 mL solution)
= 1190 g solution
Mass of NaHCO3 = 1190 g solution × (7.06 g NaHCO3/100 g solution)
= 84.01 g NaHCO3
Moles NaHCO3 = 84.01 g NaHCO3 × (1 mol NaHCO3/74.01 g NaHCO3)
= 1.14 mol NaHCO3
<em>c</em> = 1.14 mol/1 L = 1.14 mol/L
<em>Molal concentration</em>
Mass of water = 1190 g – 84.01 g = 1106 g = 1.106 kg
<em>b</em> = 1.14 mol/1.106 kg = 1.03 mol/kg
