An object is placed on a triple beam balance, and a student moves the sliders until it is balanced with the pointer resting at the zero mark. When the pointer is resting, these are the positions of the sliders: What is the mass of the object? 340.9 g
493.9 g
439.0 g
934.1 g

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).