The initial mass of sodium hydroxide is 3.3 g (answer C)
<u><em>calculation</em></u>
Step 1 : find the moles of iron (ii) hydroxide ( Fe(OH)₂
moles = mass÷ molar mass
from periodic table the molar mass of Fe(OH)₂ = 56 + [16 +1]2 = 90 g/mol
moles is therefore = 3.70 g÷ 90 g/mol = 0.041 moles
Step 2: use the mole ratio to calculate the moles of sodium hydroxide (NaOH)
from given equation NaOH : Fe(OH)₂ is 2 :1
therefore the moles of NaOH = 0.041 x 2 = 0.082 moles
Step 3: find mass of NaOH
mass = moles x molar mass
from the periodic table the molar mass of NaOH = 23 +16 +1 = 40 g/mol
mass = 0.082 moles x 40 g/mol = 3.3 g ( answer C)
Answer:
The lithosphere is made up of pieces of tectonic plates. These plates are constantly changing and move towards the mantle. Non-stop movement of tectonic plates causes stress on the earth's outermost layer i.e,the crust. When these stresses extends it leads to cause cracks called faults.
Explanation:
Answer:
+15.8°
Explanation:
The formula for the observed rotation (α) of an optically active sample is
α = [α]<em>lc
</em>
where
<em>l</em> = the cell path length in decimetres
<em>c</em> = the concentration in units of g/100 mL
[α] = the specific rotation in degrees
1. Convert the concentration to units of g/100 mL
2. Calculate the observed rotation
This correct option is C.
10^-2 = 0.001
8.7 * 10^-2 = 8.7 * 0.001 = 0.0087
Thus, 8.7 * 10^-2 is equivalent to 0.0087.
Heat of vaporization of water will be required as water is already at it's boiling point thus heat required will be 540*10=5400 cal
