A student is using different colored beads to represent different elements to model the following chemical reaction: Na2S + HCl → NaCl + H2S

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A student noticed that an equation is unbalanced. After balancing the equation, how many white beads does the student need on the product side to show that mass is conserved after the reaction?

A.
4

B.
2

C.
3

D.
5

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.