Answer: 6.38 moles of
are needed to react with 2.55 mol of 
Explanation:
The balanced chemical reaction for the combustion of ethyne is:

According to stoichiometry:
2 moles of
require = 5 moles of 
Thus 2.55 mol of
require =
moles of 
Thus 6.38 moles of
are needed to react with 2.55 mol of 
Answer:
1.07 g Ba
Explanation:
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In this case, according to the definition of the Avogadro's number and the molar mass, it is possible to say that 6.022x10^{23} atoms of barium equal one mole, and at the same time, 1 mole equals 137.327 grams of this element; thus, it is possible to say that 6.022x10^{23} atoms of barium have a mass of 137.327 grams; therefore, it i possible for us to calculate the required mass in grams as shown below:

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Answer:
The attractive forces must be overcome are :
Explanation:
For the compound to dissolve the attractive forces existing between atoms of the compound must be reduced
<u>CsI is ionic compound </u><em>and its molecules are held together by ionic(electrostatic) force . These force must be weakened for its dissolution</em>
Forces in HF <em>:</em>
<em>1 .Hydrogen Bonding : In HF strong intermolecular Hydrogen Bonding exist between the electronegative F and Hydrogen</em>
2. Dipole - dipole : <em>HF is polar . So it is a permanent dipole and has dipole diople interaction</em>
C. Rubbing the balloon against your hair