<span> The Alkali elements are so reactive that they are </span><span>never found alone in nature</span>
Answer:
hydrogen oxygen or nitrogen
Answer:
The initial temperature is 499 K
Explanation:
Step 1: Data given
initial volume = 12 cm3 = 12 mL
Final volume = 7 cm3 = 7mL
The final temperature = 18 °C = 291 K
Step 2: Calculate the initial temperature
V1/T1 = V2/T2
⇒with V1 = the initial volume = 0.012 L
⇒with T1 = the initial volume = ?
⇒with V2 = the final volume 0.007 L
⇒with T2 = The final temperature = 291 K
0.012 / T1 = 0.007 / 291
0.012/T1 = 2.4055*10^-5
T1 = 0.012/2.4055*10^-5
T1 = 499 K
The initial temperature is 499 K
The given question is incomplete. the complete question is:
The world burns the fossil fuel equivalent of approximately 
kg of petroleum per year. Assume that all of this petroleum is in the form of octane. Calculate how much CO2 in kilograms is produced by world fossil fuel combustion per year.( Hint: Begin by writing a balanced equation for the combustion of octane.)
Answer: 
Explanation:
Combustion is a chemical reaction in which hydrocarbons are burnt in the presence of oxygen to give carbon dioxide and water.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
To calculate the moles :
According to stoichiometry :
As 2 moles of octane give = 16 moles of 
Thus 
of octane give =
of
Mass of 
Thus of is produced by world fossil fuel combustion per year.
Answer:
Outside air
Nose
Lungs
Bloodstream
Cell
Explanation:
We breathe in oxygen from the outside air in through our nose and it travels to our lungs. Inside our lungs, we have Avioli's that diffuse oxygen into our bloodstream and the bloodstream helps the oxygen travel into our cells.
Hope this helps :)
