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Arlecino [84]
3 years ago
6

Please help! brainliest to correct answer!!

Chemistry
2 answers:
belka [17]3 years ago
6 0
The answer is 10 min

ElenaW [278]3 years ago
3 0

Answer: 10 minutes

Explanation:

ln(No/N) = kt

No = 80 mg

N = 10 mg

t = 30 min

solve for k, then

k = 0.693/t1/2

Substitute k from above and solve for t1/2

10 min is correct.

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A very hot cube of copper metal (32.5 g) is submerged into 105.3 g of water at 15.4 0C and it reach a thermal equilibrium of 17.
zysi [14]

Answer:

The initial temperature of the metal is 84.149 °C.

Explanation:

The heat lost by the metal will be equivalent to the heat gain by the water.  

- (msΔT)metal = (msΔT)water

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-ΔT = 836.29/12.51 °C

-ΔT = 66.89 °C

-(T final - T initial) = 66.89 °C

T initial = 66.89 °C + T final

T initial = 66.89 °C + 17.3 °C

T initial = 84.149 °C.

7 0
3 years ago
Pleas help me!
xeze [42]

Answer:

Explanation:

Question 1:

atomic number/number of protons

All atoms of the same element share the same number of protons or atomic numbers. In grouping elements on the periodic table, the periodic law is often used. The modern periodic law states that "properties of elements are a periodic function of their atomic number". The atomic number of an element distinguish it from others.

Question 2:

The two carbon atoms would be quite different as they are isotopes. Isotopy is the existence of two or more atoms of the same element having  the same atomic number but different mass numbers due to the differences in the number of neutrons in their various nuclei.

Naturally, carbon exists in two isotopic forms:

                        ¹³₆C and ¹⁴₆C

One might see these different samples in a rock and in the skin cells. They are simply isotopes. Isotopes have the same electronic configuration and hence similar chemical properties. Only their masses differ.

4 0
4 years ago
Read 2 more answers
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dimulka [17.4K]

Answer:

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Explanation:

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The answers include:

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This involves the formation of a new products from substances. In this scenario, a rising bread contains alcohol which evaporates.

Photographs also fall under this category and is therefore an irreversible chemical change.

Read more about Chemical change here

brainly.com/question/1222323

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2 years ago
A 250 ml flask and stopper have a mass of 110.525 g. A 50 ml sample of gasoline is pipetted into the flask, giving a total mass
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