Na 2Co3
1*23=23. 2*12=24. 6*16=96
23+24+96=143
(23*100)/143. (24*100)/143. (96*100)/143
=16%. =16.7%. =67.1%
Answer:
Because you can physically see the object melting when it comes to the melting point. The objects texture, color, temperature, shape, and state of matter (solid, liquid, gas) are possibly changing.
Answer:
Lichens can be used as air pollution indicators, especially of the concentration of sulphur dioxide in the atmosphere. Lichens are organisms that grow in exposed places such as rocks or tree bark. They need to be very efficient at absorbing water and nutrients to grow there.
Answer: X could represent the element of oxidation state (+2) such as (Mg2+, Pb2+, Ba2+, Ca2+, Ba2+, Zn2+, ....etc)
Explanation:
- The formula of the compound XSO4 is a neutral compound that the algebraic summation of the oxidation states of different elements in it must be zero.
- The group SO4 has the oxidation state (2-), that S has (6+) oxidation state and O has (2-) oxidation state, so the oxidation of SO4 = (6+) + (-2*4) = -2.
- It is clear that X must have the oxidation state 2+.
- So, X could be represents by many different elements such as (Mg2+, Pb2+, Ba2+, Ca2+, Ba2+, Zn2+, Fe2+, ....etc)
