Which is the following statements is correct :
1- The use of paper for weighing is not acceptable practice for quantitative determination.
2- Cleaning solution is prepared from sodium dichromate and nitric acid.
3- Volumetric glassware shouldn’t be calibrated before use.
4- Chemical are placed directly on the balance pane.
5- The object to be weighing shouldn’t be at room temperature.

If we compare and contrast electromagnetic waves with sound waves, all but one statement is true. that is a) sound waves require a medium to travel while electromagnetic waves do not. b) electromagnetic waves can travel through the vacuum of space while sound waves cannot. c) electromagnetic waves must have a medium in which to travel, but sound waves can travel anywhere. eliminate d) sound waves must bounce off of matter in order to travel while electromagnetic waves do not require matter to be present.

Apound is approximately 0.45 kilogram. a persons weighs 87 kilograms. what is the persons’s weight, in pounds, when expressed to the correct number of significant figures

How does the digestive system interact with the circulatory system? a. messages sent as electrical impulses from the digestive system are transported throughout the body by the circulatory system. b. nutrients taken in and broken down by the digestive system are carried to various parts of the body by the circulatory system. c. nutrients and gases are absorbed by organs in the circulatory system. then, they are transported to all parts of the body by organs in the digestive system. d. oxygen and carbon dioxide are exchanged by organs in the digestive system, and the gases are carried to the rest of the body by the circulatory system.