Answer:
18.
Explanation:
1) according to the reaction (M(Fe)=56; M(O₂)=32; V₀=22.4):
4Fe+3O₂⇒2Fe₂O₃; - ν(O₂)=0.75*ν(Fe);
2) ν(Fe)=m(Fe)/M(Fe)=60/56≈1.071 [mol];
3) ν(O₂)=0.75*1.071=0.804 [mol];
4) V(O₂)=V₀*ν(O₂); ⇒ V(O₂)=22.4*0.804=18 [lit].
Due to the law of conservation of energy we know that the energy that heated the surrounding had to have come from the reaction which means that the wood (with oxygen since this is combustion) lost 12000J. The change in energy for the wood is negative. I hope this helps. Let me know if anything is unclear.
Answer
Ultraviolet
Explanation
The types of radiation and their wavelength are:
Gamma < 10⁻¹² m
X-rays 1 nm - 1 pm
Ultraviolet 400 nm - 1 nm
Visible 750 nm - 400 nm
Near-infrared 2.5 μm - 750 nm
Infrared 25 μm - 2.5 μm
Microwaves 1 mm - 25 μm
Radio waves > 1 mm
Hence, the given wavelength of 2.86 X 10⁻⁸ m corresponds to Ultraviolet.
Answer:hit with force when moving.
Explanation:
Example: The two cars collided with an ear-splitting crash. to clash; conflict: Their views on the matter collided.