3 bc Hf is an element hafnium and HF is compound hydrogen flouride
Answer:
Explanation:
From the given information:
mass = 3.42 kg = 3420 g
molar mass of = 59 g
Number of moles of
Number of moles of
= 57.966
number of hydrogen atoms present =
where;
number of hydrogen atoms present
Answer: She could have put a steel spoon into the vessel. The correct option is A.
Explanation:
When a candle wax is passed through heat, it is capable of melting within 10- 15 minutes of boiling. Therefore it is not capable of looking the same after 30 mins of heating.
When sugar is put into water it dissolves. When heated it has the ability to crystallize out after water is evaporated but doesn't retain its shape.
A piece of chocolate will melt the instance it comes in contact with any form of heat.
A steel spoon is an alloy metal which is not capable of melting by boiling in water for just 30 minutes. A steel is an alloy of Iron and carbon which melts when superheated at the temperature of 1510 degrees.
Answer:
14.3mL you require to reach the half-equivalence point
Explanation:
A strong acid as HClO₄ reacts with a weak base as CH₃CH₂NH₂, thus:
CH₃CH₂NH₂ + HClO₄ → CH₃CH₂NH₃⁺ + ClO₄⁻
As the reaction is 1:1, to reach the equivalence point you require to add the moles of HClO₄ equal to moles CH₃CH₂NH₂ you add originally. Also, half-equivalence point requires to add half-moles of CH₃CH₂NH₂ you add originally.
Initial moles of CH₃CH₂NH₂ are:
20.8mL = 0.0208L × (0.51mol CH₃CH₂NH₂ / 1L) =
0.0106moles CH₃CH₂NH₂
To reach the half-equivalence point you require:
0.0106moles ÷ 2 = 0.005304 moles HClO₄
As concentration of HClO₄ is 0.37M, volume you require to add 0.005304moles is:
0.005304 moles HClO₄ ₓ (1L / 0.37mol) = 0.0143L =
<h3> 14.3mL you require to reach the half-equivalence point</h3>
When fully bonded to other atoms, the four bonds of the carbon atom are directed to the corners of a tetrahedron and make angles of about 109.5° with each other (see chemical bonding: Bonds between atoms).