Calculate the concentration of solution (in%) obtained by adding of 200 g of water to 400 g of 30% solution: A) 20
B) 23
C) 25
D) 10
E) 15
( i found A but i doubt it)

What are the percent by mass of copper in penny lab

Which statement describes evidence of a chemical reaction? a) ice melting eliminate b) water boiling c) lighting a match d) grape juice freezing

Rocks, as they are compressed, begin forming mountains above the earth's surface when two continental plates converge. the continental crust increases in depth as the mountains grow above. the himalayan mountains formed at a convergent plate boundary in this manner. the rocks are smashed together causing them to due to the intense heat and pressure from the colliding plates and eventually forming rock. a) melt; igneous b) layer; sedimentary c) recrystallize; metamorphic d) melt into the earth's interior; metamorphic