Dark energy and dark matter seem over analyzed, although they are no different than gravity and wind. Dark energy can be the pulling caused by black holes, stars, and large planets. Dark matter also is just the effect of cosmic dust and debris pushed from explosions but also pulling caused by distant gravitational bodies.
The answer is 267.93 g
Molar mass of CaBr2 is the sum of atomic masses of Ca and Br:
Mr(CaBr2) = Ar(Ca) + 2Ar(Br)
Ar(Ca) = 40 g/mol
Ar(Br) = 79.9 g/mol
Mr(CaBr2) = 40 + 2 * 79.9 = 199.8 g/mol
The percentage of Br in CaBr2 is:
2Ar(Br) / Mr(CaBr2) * 100 = 2 * 79.9 / 199.8 * 100 = 79.98%
Now make a proportion:
x g in 79.98%
335 g in 100%
x : 79.98% = 335 g : 100%
x = 79.98% * 335 g : 100%
x = 267.93 g
Answer:
1. a)
2. a)
3. b)
4. d)
Explanation:
The disposal method is how we throw away the wastes. In a chemical lab, the correct disposal method guarantees the security of the environment and the humans and animals that may be in contact with the materials.
So:
1. Excess chemical: Because it can be toxic, it may be disposed of in the appropriate waste container, which will depend on the characteristics of the material;
2. Reaction mixture: As the excess chemical, it can be toxic, so it must be disposed of at an appropriate waste container;
3. Used filter paper: Generally, the solids in the filter paper is not toxic, so it can be thrown away in the trash can;
4. Cracked or chipped beaker: Because the beaker is made of glass, it can cut when broken, so it must go to a broken glass box, that will protect the people that will deal with it.
Answer:
the molecules of each substance attract each other through dispersion (London) intermolecular force.whether a substance is solid, liquid or gas depends on the balance between the kinetic energies of the molecules and their intermolecular attractions.
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