How does the law of conservation of mass apply to this reaction mg+hcl-> h2+mgcl2?

Law of conservation of mass do not apply to this equation.

Explanation:

The law of conservation of mass states that the mass of objects/element before any reaction must be equal to the mass of objects/element after the reaction.  

Here in this case –  

Mg+HCL->H2+MgCl2

Mass of Mg before reaction = 1

Mass of H before reaction = 1

Mass of Cl before reaction = 1

Mass of Mg after reaction = 1

Mass of H after reaction = 2

Mass of Cl after reaction = 2

Thus it is clear that mass of H and Cl before and after the reaction is not equal and thus law of conservation of mass do not apply to this equation.

1 - wave length

2 - amplitude

3 - crest

4 - trough

explanation:

duh.

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.