Identify each statement as a hypothesis, theory, or law.
hypothesis
theory
law
For any closed system, the
mass of the system must
remain constant over time.
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Higher air pressure causes
fuel to burn at a faster rate.
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Organisms have changed
and diversified over time
due to shifting frequencies
of heritable traits by means
of natural selection.
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Yes, endothermic means it turns cold. and some chemical changes include change of tempature.

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The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf