D an average train goes 300 km/h or 190-220 mph
Answer:
Balanced chemical equation:
NO₂ + NO₃ → N₂O₅
Explanation:
Chemical equation:
NO₂ + NO₃ → N₂O₅
Balanced chemical equation:
NO₂ + NO₃ → N₂O₅
Nitrogen trioxide gas combine with nitrogen dioxide gas and form nitrogen pentoxide.
This is the simple synthesis reaction in which two substance combine to form a new substance.
Synthesis reaction:
It is the reaction in which two or more simple substance react to give one or more complex product.
General chemical equation:
A + B → AB
A and B are reactants that combine to form AB product.
Answer: The kilograms of water must evaporate from 8kg of a 25% salt solution to produce 40% salt solution is 3 kg.
Explanation:
According to the ratio and proportion:

where,
= concentration of ist solution = 25%
= mass of ist solution = 8 kg
= concentration of second solution = 40%
= mass of second solution = ? kg


Thus the final solution must have a mass of 5 kg , i.e (8-5)= 3 kg of mass must be evaporated.
Therefore, the mass that must be evaporated from 8kg of a 25% salt solution to produce 40% salt solution is 3 kg.
<u>Answer:</u> The magnitude rating for an earthquake causing an amplitude 10,000,000 times
is 7.
<u>Explanation:</u>
Richter scale is defined as the scale which expresses the magnitude of earthquake on the basis of the seismograph oscillations.
The equation used to measure the magnitude of an earthquake on Richter scale is:

where
I = amplitude registered on seismograph 100 km away from seismic center = 
= small amplitude
Putting values in above equation, we get:

Hence, the magnitude rating for an earthquake causing an amplitude 10,000,000 times
is 7.
Answer:
B - To increase the rate of the reaction
Explanation:
Catalysts speed up the reaction without being reactants or products, so aren't used up in the reaction.