Which of these represents a chemical change?
a)
two compounds combining to form a mixture
b)
a mixture being separated into two elements
c)
a compound being separated into two elements
d)
an element changing state from solid to liquid

answer: option (a) is the correct answer.

explanation:

a chemical change is a change which occurs when chemical composition of a substance changes.

for example, when hcl is added to naoh then it results in the formation of a salt and water. this means that the chemical composition of reactants has changed.

the reaction is as follows.

thus, we can see that two compounds combine to form a mixture which is nacl in the above reaction.

whereas when we heat solid ice then it gets melted which shows that only the state has changed. hence, there is no change in its chemical composition because when we freeze liquid water then it will again turn into solid ice. therefore, it is a physical change.

hence, we can conclude that two compounds combining to form a mixture represents a chemical change.

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.

1 the 4 is sig