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4 years ago

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Which one is a true statement about endothermic reactions? a: More heat is given off than is put into the reaction. b :The react

ants have more heat energy than the products. c: The reaction container always feels hot. d: Energy is absorbed making it feel colder.

1 answer:

Setler [38]4 years ago

7 0

A because it gets hot

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Reactions which do not continue to completion are called _____reactions

SIZIF [17.4K]

I think the answer is reversible. Reversible reaction is a kind of reaction which can react in both direction at the same time. And when the both side reactions get the same speed, the reaction is at a equilibrium state.

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3 years ago

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I got c, just wondering was it right?

Talja [164]

Answer:

Yes you are right.

Explanation:

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3 years ago

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If 12.5 grams of the original sample of cesium-137 remained after 90.6 years, what was the mass of the original sample?

myrzilka [38]

Answer:

Mass of original sample = 100 g

Explanation:

Half life of cesium-137 = 30.17 years

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac{\ln2}{t_{1/2}}$

$k=\frac{\ln2}{30.17}\ year^{-1}$

The rate constant, k = 0.02297 year⁻¹

Time = 90.6 years

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Initial concentration $[A_0]$ = ?

Final concentration $[A_t]$ = 12.5 grams

Applying in the above equation, we get that:-

$12.5\ g=[A_0]e^{-0.02297\times 90.6}$

$[A_0]=\frac{12.5}{e^{-0.02297\times 90.6}}\ g=100\ g$

<u>Mass of original sample = 100 g</u>

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3 years ago

I WILL GIVE U BRAINLIESTt!!!!!!!!!!!

nirvana33 [79]

I would say b and d but I wouldn’t really know :/

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4 years ago

A certain ore is 37.3% nickel by mass how many kilograms of this ore would you need to dig up to have 10.0g of nickel

jeka57 [31]

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3 years ago