Why did the french became allies with the american? Answers:
To get revenge for recent French losses in North America

To gain territory in the west

To protect the iroquols from British attacks

No, it is not possible to make CD by other material except plastic.

The full form of CD is compact disks. It is simple disk of plastic

Why CD made up of plastics ?

• The CD is made up of plastic mainly with polycarbonate plastic (PC) .

• The PC is stronger  and mechanically more stable. CD must be stronger enough to resist any mechanical damage like scratching.
• The PC are quite temperature and and impact resistance and highly transparent.
• It provides the disc depth necessary to maintain laser focus on the metal and data layer.
• The surface of the CD is reflective because it is coated with thin layer of aluminium and sometimes gold .

learn about Aluminium

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Decrease, increase and increase I think this is correct

The muscles of the body are part of the musculoskeletal system but would not operate without the nervous system providing the impulses that cause the muscles to act. Correct answer: C The nervous system controls all activities within the human body, including the muscles. It sends messages between the brain and the muscles very quickly using nerve impulses (action potentials).

Nervous is the system that provides impulse

Answer:  Ca(OH)2 = Ca2+ + 2 OH-  

the ratio between Ca(OH)2 and OH- is 1 : 2

Explanation: [OH-]= 2 x 0.00034 = 0.00068 M  

[H+]= Kw/[OH-]= 1.0 x 10^-14 / 0.00068 =1.5 x 10^-11 M ( at two significant figures)  

HCl is a monoprotic acid  

[H+]= 0.00031 M  

[OH-]= Kw/[H+]= 1.0 x 10^-14 / 0.00031 =3.2 x 10^-11 M  

[OH-]= 0.047 M  

[H+]= 1.0 x 10^-14 / 0.047 =2.1 x 10^-13 M

Answer:

848.1 g/mol

Explanation:

Data given:

Standard of atomic mass of Ca = 50 amu

molar mass of Aluminium Acetate = ?

Solution:

Relative atomic mass represented by Ar. It is ratio of actual mass with respect to the 1/12th mass of C-12 but here Ca-50 is standard.

Formula of  Aluminium Acetate = Al(CH₃COO)₃

In order to calculate Ar

first we will calculate 1/50 of Ca

As we know

         mass of 1/12 of C-12 = 1.993 x 10⁻²⁶/12 = 1.661 x 10⁻²⁷ Kg

So, for Ca-50

        mass of 1/50 of Ca-50 = 1.993 x 10⁻²⁶/50 = 3.986 x 10⁻²⁸ Kg

Now

 Relative Atomic mass for element X = rest mass of "X"/ 3.986 x 10⁻²⁸ Kg . . . . . . (1)

First we have to know the relative atomic masses of Aluminium, carbon, hydrogen, oxygen atoms involve in Aluminium Acetate formula with respect to new standard Ca-50

By using equation-1 we can calculate Ar for which we have reported rest masses of atoms as below

Rest mass of Aluminium = 4.48 x 10⁻²⁶ Kg

Rest mass of carbon = 1.993 x 10⁻²⁶ Kg

Rest mass of hydrogen = 1.608 x 10⁻²⁷ Kg

Rest mass of oxygen = 2.657x10⁻²⁶ Kg

Now put values in equation 1 for each atom

• Ar for Aluminium= 4.48 x 10⁻²⁶Kg / 3.986 x 10⁻²⁸ Kg

                     Ar for Aluminium = 112.5  amu

• Ar for Carbon= 1.993 x 10⁻²⁶ Kg / 3.986 x 10⁻²⁸ Kg

                     Ar for Carbon= 50 amu

• Ar for Hydrogen = 1.608 x 10⁻²⁷ Kg / 3.986 x 10⁻²⁸ Kg

                     Ar for hydrogen = 4  amu

• Ar for Oxygen = 2.657x10⁻²⁶ Kg / 3.986 x 10⁻²⁸ Kg

                     Ar for Oxygen = 66.6  amu

Now find the molar mass ofAl(CH₃COO)₃

molar mass of Aluminium Acetate = Al(CH₃COO)₃

Al(CH₃COO)₃ = 112.5 + 3 (50 + 3(4) + 50 + 66.6 +66.6)

Al(CH₃COO)₃ = 112.5 + 3 (50 + 12 + 50 + 66.6 +66.6)

Al(CH₃COO)₃ = 112.5 + 3 (245.2)

Al(CH₃COO)₃ = 112.5 + 735.6

Al(CH₃COO)₃ = 848.1 g/mol

molar mass of Aluminium Acetate = 848.1 g/mol