Answer:
Density
Explanation:
Density is defined as the mass per unit volume. It is the ratio between the mass and the volume of a substance. It does not matter how large or small a sample of matter is, the same substance will always have the same density, because of this. The ratio between the mass and volume remains the same.
I think is true i took the test but im not sure what i put! Correct me if wrong
On Earth it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium<span> present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of </span>helium<span>-4 nuclei.</span>
You may find bellow the balanced chemical reactions.
Explanation:
To balance chemicals equation the number of atoms of each element
entering the reaction have to be equal to the number of atoms of each
element leaving the reaction, in order to conserve the mass.
2. Single displacement: Zn + 2 HCl → ZnCl₂ + H₂
3. Decomposition: NiCl₂ → Ni + Cl₂
4. Double displacement: 2 LiI + Pb(NO₃)₂ → PbI₂ + 2 LiNO₃
5. Double displacement: BaCl₂ + H₂SO₄ → BaSO₄ + 2 HCl
6. Single displacement: Cu + 2 AgNO₃ → Cu(NO₃)₂ + 2 Ag
7. Synthesis (combination): 2 Na + O₂ → 2 Na₂O
8. Solid mercury (II) oxide decomposes to form liquid mercury and oxygen.
2 HgO (s) → 2 Hg (l) + O₂ (g) (decomposition reaction)
9. A solution of zinc hydroxide reaction with phosphoric acid (H₃PO₄) to produce solid zinc phosphate and water.
3 Zn(OH)₂ + 2 H₃PO₄ → Zn₃(PO₄)₂ (s) + 6 H₂O (l) (double displacement reaction)
where:
(s) - solid
(l) - liquid
Learn more about:
types of chemical reactions
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