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3 years ago

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The rare earth elements include A. the actinide series and the alkaline earth metals. B. the alkali metals and the transition me

tals. C. the lanthanide series and the actinide series. D. the lanthanide series and the alkali metals.

1 answer:

kolezko [41]3 years ago

8 0

The answer is A because Alkaline are gases in earth's atmosphere <span />

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Which units represent destiny? Select all that apply.

ozzi

The basic units for density is $\frac{mass}{volume}$ and any get of units that has those units in the proper place can be considered a density unit. The ones that has those specifically are A, B, E and F

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3 years ago

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Which would exert more pressure on the floor, a 100kg man wearing snow shoes or a 60kg woman wearing high heels? PLEASE EXPLAIN

iris [78.8K]

Pressure can be defined as the force acting on a perpendicular surface per unit area.

Force exerted by a man of mass 100 kg wearing snow shoes = m.a

Where m = mass of the man = 100 kg

a = acceleration due to gravity= 9.8 $m/s^{2}$

Force exerted by the man of mass 100 kg = $100 kg(9.8 m/s^{2}) = 980 N$

Force exerted by woman of mass 60 kg = $60 kg(9.8 m/s^{2}) = 588 N$

Force exerted by 100 kg man is greater than that exerted as 60 kg woman. The area on which this force is acting determines the pressure. Pressure is inversely proportional to the area on which the force acts. Therefore, the pressure exerted by 100 kg man wearing snow shoes is less than the pressure exerted by a 60 kg woman woman wearing high heels as the force acts over a larger area when the man wears snow shoes when compared to the force exerted over a smaller area in case of the woman wearing high heels.

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3 years ago

An astronaut weighs 104 newtons on the moon,where the strength of gravity is 1.6 newtons per kilogram

belka [17]

I'd say he ways about 35 kilograms, but I'm probably wrong, xD

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3 years ago

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Researchers are investigating processes that happen during digestion. Which answer choice describes only a physical change durin

ElenaW [278]

The correct answer is B. Chewing in the mouth breaks food into small pieces.

Explanation:

In physical changes, substances do not change their chemical composition or properties but only physical features such as this. This occurs during the chewing because the action of chewing only makes food to be broken down in smaller pieces but does not change its identity, composition, or properties. This does not occur once the food is in contact with saliva, the acid in the stomach, etc. because in these cases, the food reacts with other substances and a chemical reaction occurs, which changes food's identity and composition.

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3 years ago

Consider the reaction: P(s) + 5/2 Cl2(g)PCl5(g) Write the equilibrium constant for this reaction in terms of the equilibrium con

Pani-rosa [81]

Answer: The equilibrium constant for the overall reaction is $K_a\times K_b$

Explanation:

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios.

a) $P(s)+\frac{3}{2}Cl_2(g)\rightarrow PCl_3(g)$

$K_a=\frac{[PCl_3]}{[Cl_2]^{\frac{3}{2}}}$

b) $PCl_3(g)+Cl_2(g)\rightarrow PCl_5(g)$

$K_b=\frac{[PCl_5]}{[Cl_2]\times [PCl_3]}$

For overall reaction on adding a and b we get c

c) $P(s)+\frac{5}{2}Cl_2(g)\rightarrow PCl_5(g)$

$K_c=\frac{[PCl_5]}{[Cl_2]^\frac{5}{2}}$

$K_c=K_a\times K_b=\frac{[PCl_3]}{[Cl_2]^{\frac{3}{2}}}\times \frac{[PCl_5]}{[Cl_2]\times [PCl_3]}$

The equilibrium constant for the overall reaction is $K_a\times K_b$

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3 years ago