Answer:
The nswer to the question is
The maximum fraction of the air in the room that could be displaced by the gaseous nitrogen is 0.548 or 54.8 %
Explanation:
To solve the question we note that 
The density of the liquid nitrogen = 0.808g/mL and the volume is 195 L tank (vaporised)
Therefore since density = mass/volume we have
mass = Density × volume = 0.808 g/mL × 195 L × 1000 ml/L =157560 g
In gaseous form the liquid nitrogen density =1.15 g/L
That is density = mass/volume and volume = mass/density = 157560 g/(1.15g/L)  or 
volume = 137008.69565 L
The dimension of the room = 10 m × 10 m × 2.5 m = 250 m³ and
1 m³ is equivalent to 1000 L, therefore 250 m³ = 250 m³  × 1000 L/m³ = 250000L
Therefore fraction of the volume occupied by the gaseous nitrogen =
137008.69565 L/250000 L = 0.548
 Therefore the gaseous nitrogen occpies 54.8% of the room
 
        
             
        
        
        
Answer:
3626.76dm³
Explanation:
Given parameters: 
Number of moles of Nitrogen in tank = 17moles
Temperature of the gas = 34°C
Pressure on the gas = 12000Pa
Unkown: 
Volume of the tank, V =?
Converting the parameters to workable units: 
We take the temperature from °C to Kelvin
K = 273 +  °C  = 273 + 34 = 307k
Taking the pressure in Pa to atm: 
101325Pa = 1atm
12000Pa = 0.118atm
Solution: 
To solve this problem, we employ the use of the ideal gas equation. The ideal gas law combines three gas laws which are the Boyle's law, Charles's law and the Avogadro's law. 
             It is expressed as PV = nRT
The unknown is the Volume and we make it the subject of the formula
              V = 
Where R is called the gas constant and it is given as 0.082atmdm³mol⁻¹K⁻¹
Therefore  V =  = 3626.76dm³
 = 3626.76dm³
 
        
                    
             
        
        
        
Answer:
a) formula for citric acid is - C6 H8 o7 
b) lime water turns opaque after adding co2 due to the formation of calcium carbonate. 
c) reaction 3 is displacement reaction where a high reactive metal displace a less reactive from its salt solution. 
d) reaction 1) is combination reaction where two reactant combines to give a single product whereas reaction 2) is decomposition reaction where a single reactant splits into more that 1 products. 
 
        
             
        
        
        
Burning, cooking
Explanation:
Chemical changes that happens in school are: 
 Cooking of meals
  Burning of wastes
  Chemical reactions in laboratories
Rusting of iron used in construction
- A chemical change is a change that produces new kinds of substances. 
- These changes are usually accompanied by energy and mass changes. 
- Most of such changes are not reversible. 
Chemical changes are driven by change in chemical properties of matter. 
In a school, iron components might begin to rust. This is a chemical change. 
learn more: 
Chemical change brainly.com/question/9388643
#learnwithBrainly
 
        
             
        
        
        
Answer:
Since one banknote has a thickness of about 0.1 millimeters, if all the banknotes produced in a year were stacked up, they would reach a height of approximately 300 kilometers, which is about 80 times the height of Mount Fuji.