An energy of 25kJ is given out hence the reaction is exothermic.
<h3>What is a reaction?</h3>
Chemical reaction is said to occur when reactants combine leading to the formation of products. In a plot of the energy against the reaction profile, the topmost point of the graph is called the activation energy.
We know that a reaction is exothermic when reactants posses more energy than the products. Hence the enthalpy change for this reaction is;
ΔH = 5kJ - 30kJ = -25kJ thus the reaction is an exothermic reaction.
Now, the activation energy for the lighting of the match stick is high that is why a spark is required before the reaction gets underway. Heat is evolved in the process hence the reaction is exothermic. The energy of the reactants is greater than the energy of the products.
Learn more about exothermic reaction:brainly.com/question/10373907
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Answer:
D)they would generate so much power that they would blow themselves apart.
Explanation:
Stars contains helium and hydrogen gases with helium forming a large percentage. When a star is a few times greater than the Sun it could cause it to collapse into a black hole.
However when the mass of the star is 200 times greater than the sun, it means a larger percentage of helium gas which is formed by the fusion of hydrogen nuclei with a large amount of energy being the by product of this fusion process. This would make the Stars generate so much power that they would blow themselves apart.
Answer:
b.The frictional force and force exerted by the spring scale on the block, because they are a Newton's third-law pair.
Explanation:
Students connect a spring scale to a block on a rough horizontal surface. The students use the spring scale to measure the magnitude of the horizontal force needed to pull the block at a constant speed. Which of the following statements explains why two forces exerted between objects ar equal in magnitude?
a.A The gravitational and normal forces exerted on the block, because they are a Newton's third-law pair.
b.The frictional force and force exerted by the spring scale on the block, because they are a Newton's third-law pair.
c.The normal force and the frictional force exerted on the block, because objects always exert forces of equal magnitude on each other.
d.The frictional forces that the block and the surface exert on each other, because objects always exert forces of equal magnitude on each other.
solution \
the answer will be B
for a body to travel in a horizontal direction, it must be equal in direction to the frictional force which is in opposite direction to the force applied to move the block.
Also Newton's third law of motion must be obeyed , which states that action and reaction are equal and opposite
Answer: The reason for the differences in density is the composition of rock in the plates. When two plates come in contact with each other through plate tectonics, scientists can use the density of the plates to predict what will happen. Whichever plate is more dense will sink, and the less dense plate will float over it.
Explanation:
Hope this helps ( not copied and pasted, this answer was done by me so I don't know if it's good or not)