Answer:
See explanation
Explanation:
 1 mole of a gas occupies 22.4 L
x moles occupies 16.8 L
x = 1 mole *  16.8 L/22.4 L
x = 0.75 moles 
number of moles = mass/molar mass
mass =  number of moles  * molar mass
mass =  0.75 moles * 30.01 g/mol = 22.5075 g = 2.25 * 10^1 g
the coefficient of the scientific notation answer = 2.25 
the exponent of the scientific notation answer = 1
significant figures are there in the answer = 6
 the right most significant figure in the answer = 3
2. 
number of moles = 12.5g/38g/mol = 0.3289 moles
1 mole occupies 22.4 L
0.3289 moles occupies 0.3289 moles * 22.4 L/1 mole
= 7.36736 L = 7.36736 * 10^0 L= 7.37 * 10^0 L
the coefficient of the scientific notation answer =7.37
the exponent of the scientific notation answer = 0
significant figures are there in the answer = 6
the right most significant figure in the answer= 3
 
        
             
        
        
        
Answer:
ΔT = 0.78 °C
Explanation:
Given data:
Mass of Al = 9.5 g
Specific heat capacity of Al = 0.9 J/g.°C
Temperature change = ?
Heat added = 67 J
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
67 J = 9.5 g × 0.9 j/g.°C × ΔT
67 J = 85.5 j/°C × ΔT
ΔT = 67 J  /  85.5 j/°C
ΔT = 0.78 °C
 
        
             
        
        
        
The correct option is COVALENT BONDS.
A Lewis acid is defined as a substance which accept a pair of electron while a Lewis base refers to a substance that donate an unshared pair of electrons to another chemical specie with which it shared the donated pair of electrons.
Lewis acid and Lewis base react together to form salt and water. This type of reaction is called neutralization reaction. The neutralization reaction of Lewis acid and Lewis base involves electron pairs transfer, thus, there is an increase in the number of covalent bonds during this reaction. 
 
        
                    
             
        
        
        
The question is in another language, so the English translation of the question is as follows:
Is salt-water a hom.ogeneous or heterogeneous mixture?
Answer:
Hom.ogenous mixture
Explanation:
There are two types of mixtures hom.ogenous and hetergenous.  a heterogeneous mixture has two or more visible phases while a hom.ogeneous mixture is composed of a single visible phase.
The salt-water is hom.ogeneous because the solve dissolve evenly in throughout the entire salt-water sample and gives visible phase.
Hence, the correct option is "hom.ogenous mixture".
 
 
        
             
        
        
        
 The accepted model of the atom was changed.