Answer:
A_____PENCIL______ consists of a mixture of graphite powder (a form of carbon) and clay that is baked and hardened and encased in wood or paper. a. silverpoint b. pencil c. charcoal d. chalk e. paste
Explanation:
A pencil is a writing material, where the graphite is what gives the black color to the writing stroke.
<u>Answer:</u>
<em>Silver tarnishing as the silver metal reacts with sulphur is a chemical change.</em>
<u>Explanation:</u>
Tarnishing is the process of chemical change occurring on the surface of objects leading to corrosion or other defects on the surface. The remaining options like dilution, eroding is a physical change where the concentration of salt and rock particles will be decreased, respectively.
Similarly for soil drying also the concentration of water will be decreased leading to a physical change from wetty or dry soil.
But the last option which indicates tarnishing of silver metal on reaction with sulphur is a chemical process as the surface of silver metal will be reacting to sulphur and leads to lose of electrons which leads to corrosion of the surface or tarnishing of silver.
Answer:
D. Electron pairs repelling each other push atoms apart
Explanation:
Hope this helps :) I just got it wrong on ap3x so I'm sure this is right
A. A group of related objects that do not send out or receive feedback and cannot modify themselves
Explanation:
An open-loop system is a a group of related objects or systems that cannot send out or receive feedback and modify themselves.
- It is a non-feedback system.
- In this system, the output control system has no effect on whatever input that is fed into the system.
- Output and input in such systems are independent of one another.
- The input and output has no control whatever on each other.
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