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
Covalent compounds have bonds where electrons are shared between atoms. Due to the sharing of electrons, they exhibit characteristic physical properties that include lower melting points and electrical conductivity compared to ionic compounds.
Combining oxygen gas and hydrogen gas to form liquid water is a chemical change. Pretty sure the rest are physical changes because a chemical change happens when a substance is altered completely. A physical change is when a substance keeps its components (I dunno what word to use) but just changes into a diferent shape. At least thats how my teacher explained it to me.
(For a bit of context I will use the reaction between HCl and Mg as an example)
The larger the surface area of the magnesium metal, the more particles are exposed to collide with the aqueous HCl particles to cause the reaction to occur. This increases the frequency per second of collisions, speeding up the rate of reaction.
The effect of a catalyst is to reduce the minimum collision energy which allows the reaction to happen. This does not increase the number of collisions per second, but increases the percentage of successful collisions, which consequently causes the rate of reaction to increase .
I have drawn diagrams showing the effect of surface area, but there isn't really a meaningful diagram that I know of to show the impact of a catalyst (at least not at GCSE level).