There are 4 things that are evidence of a chemical change.
1)Change in color
2)Change in shape (gas being let out)
3)Change in temperature
4)Change in smell
Burning wood is a chemical change because it has a change in color, and shape.
Answer:An atom
Explanation:
Because molecules more spread out and have things that connnect them and are not bunched up togoether
And Atoms are all packed up like in the picture
Hope this helps!:D
Answer:
A. Engineers come up with scientific questions when they are developing their design, and scientists do research to answer them.
Answer:Trials are repetitions of the same procedure. These are done for a couple of reasons: To minimize the impacts of errors done in any one trial by averaging multiple trials together. To minimize random effects and the effects of uncontrolled variables by averaging multiple trials together.
Explanation:
This is a dilution that requires a certain volume from the stock solution to be diluted with distilled water to make a solution of HBr with a lesser concentration than the stock solution
Following dilution formula can be used
c1v1 = c2v2
Where c1 is concentration and v1 is the volume of the stock solution
c2 is concentration and v2 is volume of the diluted solution to be prepared
Substituting these values
10.0 M x v1 = 3.0 x 450.0 mL
v1 = 135.0 mL
A volume of 135.0 mL from HBr stock solution needs to be taken and diluted with distilled water upto 450.0 mL. The resulting solution will have a concentration of 3.0 M
