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3 years ago

Who arranged the elements according to atomic mass and used the arrangement to predict the properties of missing element?

Chemistry

1 answer:

Marina CMI [18]3 years ago

3 0

Answer:

Dmitri Mendeleev

Explanation:

Dmitri Mendeleev a Russian Chemist arranged elements on the periodic table according to their atomic mass. He used this arrangement to predict some of the properties of the missing element.

Dmitri Mendeleev around 1869 described the periodic table.
The table was based on the periodic law which states that "chemical properties of elements are a periodic function of their atomic weights".
In the Mendeleev table, elements are arranged by atomic weights with recurring properties in a periodic manner.

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How can you tell if a chemical equation is balanced

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Answer:

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3 years ago

Identify the correct net ionic equation for the reaction that occurs when solutions of Pb(NO3)2 and NH4Cl are mixed.

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Answer:

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Explanation:

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3 years ago

If a piece of cadmium with a mass of 37.60 g and a temperature of 100.0 oC is dropped into 25.00 cc of water at 23.0 oC, what wi

zlopas [31]

Answer:

$T_{eq}=28.9\°C$

Explanation:

Hello!

In this case, since it is observed that hot cadmium is placed in cold water, we can infer that the heat released due to the cooling of cadmium is gained by the water and therefore we can write:

$Q_{Cd}+Q_{W}=0$

Thus, we insert mass, specific heat and temperatures to obtain:

$m_{Cd}C_{Cd}(T_{eq}-T_{Cd})+m_{W}C_{W}(T_{eq}-T_{W})=0$

In such a way, since the specific heat of cadmium and water are respectively 0.232 and 4.184 J/(g °C), we can solve for the equilibrium temperature (the final one) as shown below:

$T_{eq}=\frac{m_{Cd}C_{Cd}T_{Cd}+m_{W}C_{W}T_{W}}{m_{Cd}C_{Cd}+m_{W}C_{W}}$

Now, we plug in to obtain:

$T_{eq}=\frac{37.60g*0.232\frac{J}{g\°C}*100.00\°C+25.00g*4.184\frac{J}{g\°C}*23.0\°C}{37.60g*0.232\frac{J}{g\°C}+25.00g*4.184\frac{J}{g\°C}}\\\\T_{eq}=28.9\°C$

NOTE: since the density of water is 1g/cc, we infer that 25.00 cc equals 25.00 g.

Best regards!

6 0

2 years ago