Al2O3; The ___ show the ___ of each atom in the __

Making wire from a block of copper.<br><br> Physical Change<br> or<br> Chemical Change?

8090 [49]

Answer:

physical

Explanation:

3 0

3 years ago

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A lead mass is heated and placed in a foam cup calorimeter containing 40.0 mL of water at 17.0°C. The water reaches a temperatur

lbvjy [14]

Answer: 502 Joules

Explanation:

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of water = 1 g/mL

Volume of water = 40.0 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{40.0mL}\\\\\text{Mass of water}=(1g/mL\times 40.0mL)=40.0g$

When metal is dipped in water, the amount of heat released by lead will be equal to the amount of heat absorbed by water.

$Heat_{\text{absorbed}}=Heat_{\text{released}}$

The equation used to calculate heat released or absorbed follows:

$q=m\times c\times \Delta T$

q = heat absorbed by water

$m$ = mass of water = 40.0 g

$T_{final}$ = final temperature of water = 20.0°C

$T_{initial$ = initial temperature of water = 17.0°C

$c$ = specific heat of water= 4.186 J/g°C

Putting values in equation 1, we get:

$q=40.0\times 4.186\times (20.0-17.0)]$

$q=502J$

Hence, the joules of heat were re-leased by the lead is 502

5 0

3 years ago

All of the alkali earth metals, Group 2, have two valence electrons. Which of these would represent the oxidation number of the

juin [17]

Your answer should be C.) +2. "All the elements in Group 2 have two electrons in their valence shells, giving them an oxidation state of +2."

Credits: https://chem.libretexts.org/Core/Inorganic_Chemistry/Descriptive_Chemistry/Elements_Organized_by_Blo...

Hopefully this has helped! :)

5 0

3 years ago

Given that kb for c6h5nh2 is 1.7 × 10-9 at 25 °c, what is the value of ka for c6h5nh3 at 25 °c?

lina2011 [118]

Answer: $k_a$ for $C_6H_5NH_3^+$ at 25°C is $0.588\times 10^{-4}$

Explanation: We are given $k_b$ of $C_6H_5NH_2$ at 25°C which is $1.7\times 10^{-9}$

To calculate the $k_a$ of $C_6H_5NH_3^+$ , we use the formula:

$k_w=k_a\times k_b$

$k_w\text{ at }25^o=1\times 10^{-14}$

Putting values in above equation, we get:

$1\times 10^{-14}=k_a\times (1.7\times 10^{-9})\\k_a=0.588\times 10^{-5}$

7 0

3 years ago

Distinguish between an absorption spectrum and an emission spectrum. With which did Bohr work?

Marianna [84]

Answer:

Bohr used emission spectrum for its mono atomic model....

Explanation:

Emission Spectrum is produced when atoms are excited by energy. After excitation, they emit this energy in the form of different wavelengths according to the type of atom and produce a unique fingerprint of themselves called as it's emission spectrum.

Absorption Spectrum is a type of spectrum that is produces when photons of light are absorbed by electrons at one state. they jump to another state and may cause scattering. This produces a specific absorption spectrum for that specific atom.

4 0

3 years ago

Al2O3; The ___ show the ___ of each atom in the ___

Al2O3; The _ show the _ of each atom in the ___