Answer:
Chemical reactions do not involve changes in the chemical bonds that join
atoms in compounds :
<u>False</u>
Explanation:
Chemical reaction are the reaction in which old bonds break and new bonds are formed . The formation of new bond result in formation of new compounds . This happen because new bond are result of linking different atoms by the bond.
For example : Water formation from Oxygen and Hydrogen is a chemical process :
Original(old) bonds are :
H-H bond in H2 and O-O bonds in O2
In H2 = Hydrogen is joined to Hydrogen
IN O2 = Oxygen is joined to oxygen
New Bonds =
O-H bonds in water (H2O)
Oxygen is joined to hydrogen = New Bond formation
Hence,
<u>Chemical reactions do involve changes in the chemical bonds that join
</u>
<u>atoms in compounds</u>
<u />
Answer:
The final temperature of the system is 27.3°C.
Explanation:
Heat lost by aluminum = 3.99 × 0.91 × (100-T)
= 3.631 (100-T)
Heat gained by water = 10 × 4.184 × (T-21)
= 41.84 (T-21)
As,
Heat gained = Heat loss
or, 3.631(100-T) = 41.84(T-21)
or,363.1 - 3.631 T = 41.84 T - 878.64)
or, (41.84+ 3.631) T = 878.64 +363.1
or T= 
or, T = 27.3°C
Hence the final temperature is 27.3°C.
The reactants in the neutralization reaction are an acid and a base while the products are a salt and water.
For this item, we need to assume that air behaves like that of an ideal gas. Ideal gases follow the ideal gas law which can be written as follow,
PV = nRT
where P is the pressure,
V is the volume,
n is the number of mols,
R is the universal gas constant, and
T is temperature
In this item, we are to determine first the number of moles, n. We derive the equation,
n = PV /RT
Substitute the given values,
n = (1 atm)(5 x 10³ L) / (0.0821 L.atm/mol.K)(0 + 273.15)
n = 223.08 mols
From the given molar mass, we calculate for the mass of air.
m = (223.08 mols)(28.98 g/mol) = 6464.9 g
<em>ANSWER: 6464.9 g</em>
