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irinina [24]
3 years ago
8

What do the sweat collection pads tell the scientist?

Chemistry
2 answers:
Tamiku [17]3 years ago
5 0
A should be right yea bc my mom said it was
spayn [35]3 years ago
4 0
A
Is the correct answer

I’m 95% sure
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HELP ME WITH THIS AND DON'T GET ME WRONG IF YOU DON'T KNOW DON'T ANSWER AND DON'T SAY ''I THINK ITS THE RIGHT ANSWER BUT I'M NOT
tatiyna

Answer:

1 only

Explanation:

a compound is a mix of two different elements, two of the same element is just a molecule

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What is the main function of messenger RNA?
Alla [95]
The right answer is C


Messenger RNA (mRNA) carries the genetic information copied from DNA in the form of a series of three-base code “words,” each of which specifies a particular amino acid. 2. Transfer RNA (tRNA) is the key to deciphering the code words in mRNA.
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3 years ago
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To freeze/melt a substance, does the substance have to absorb it release heat?
Wewaii [24]

Answer: All solids absorb heat as they melt to become liquids.

Explanation:

5 0
4 years ago
3. Crystalline structural unit of barium metal is a body-centered cubic cell. The edge length of the unit cell is 5.02x10-8 cm.
tiny-mole [99]

Answer:

The Avogadro's  number is N_A     =  6.02289 *10^{23}

Explanation:

From the question we are told that

   The edge length is  L   = 5.02 * 10^{-8} \ cm= \frac{5.02 * 10^{-8} }{100}  =  5.02 * 10^{-10}

    The density of the metal is \rho =  5.30\ g/cm^3 = 5.30 * \frac{g}{cm^3}  * \frac{1*10^6}{1*10^3} = 5.30 *10^3kg/m^3

     The molar mass of  Ba is  Z  =  137.3 \ g/mol = \frac{137.3}{1000} =  0.1373 \  kg / mol

     

Generally the volume of a unit cell is  

       V =  L^3

substituting value

        V =  [5.02 *10^{-10}]^3

         V = 1.265*10^{-28}\ m^3  

From the question we are told that 68% of the unit cell is occupied by Ba atoms and that the structure is a metal which implies that the crystalline structure will be  (BCC),

The volume of barium atom is  

        V_a  =  \frac{V}{2}  * 0.68

substituting value

        V_a  =  \frac{ 1.265*10^{-28}}{2}  * 0.68

        V_a  = 4.301 *10^{-29} \ m^3

The Molar mass of barium is mathematically represented as

      Z  =  N_A V_a *  \rho

Where N_A is the Avogadro's number

 So  

      N_A     =   \frac{ Z}{ V_a *  \rho}

substituting value

     N_A     =   \frac{ 0.1373}{ 4.301*10^{-29} *  5.3*10^{3}}

     N_A     =  6.02289 *10^{23}

4 0
3 years ago
A semipermeable membrane separates two aqueous solutions at 20 ∘ C. For each of the cases, determine the direction, if any, of t
cupoosta [38]

Answer: 1. The total ion concentrations of both solution A and B are equal. Therefore, there is no net flow of water molecules.

2. The total ion concentrations of the solutions A is greater than that of solution B. Therefore, there is a net flow of water molecules towards A.

3. The total ion concentrations of the solutions B is greater than that of solution A. Therefore, there is a net flow of water molecules towards B.

<em>Note: The question did not provide any reference solutions and their concentrations. Assuming the following pairs of solution and their given concentrations:</em><em> </em>

1. Solution A: 0.10M NaCl(aq) Solution B: 0.10M KBr (aq)

2. Solution A: 0.20M Al(NO3)3 solution B: 0.10M NaNO3

3. Solution A: 0.10M CaCl2 Solution B: 0.50M KCl

Explanation:

An electrolyte is a chemical substance that is decomposed when an electric current is passed through it either in its molten or solution form.

When there is 100% dissociation of electrolytes, the individual ions in the substance are free to move. Therefore, it is necessary to consider the concentration of ions instead of solution concentration.  The movement of water across the semipermeable membrane depends on the concentration of ions in each solution.This net movement of water molecules through a semipermeable membrane is from a low concentrated solution to the higher concentrated solution  and is known as osmosis .

First, calculate the concentrations of each solution A and B and indicate the movement of water molecules from low to high concentrated solutions as follows.

It is given that the electrolytes dissociate 100%(completely) into ions;

1)  Solution A: 0.10M NaCl(aq) Solution B: 0.10M KBr (aq)  

Calculate the concentration of ions in solutions A and B using,

Total ion concentration =  M o l a r i t y  ×  N umber o f  ions

Solution A:  Total ion concentration =  0.10 × 2 = 0.20M

Solution B:  Total ion concentration =  0.10 × 2 = 0.20M

<em>The total ion concentrations of both solution A and B are equal. Therefore, there is no net flow of water molecules. </em>

2)  Solution A: 0.20M Al(NO3)3 solution B: 0.10M NaNO3

Calculate the concentration of ions in solutions as follows ;

Total ion concentration =  M o l a r i t y  ×  N umber o f  i ons

Solution A:  Total ion concentration =  0.20 × 4 = 0.80M

Solution B:  Total ion concentration =  0.10 × 2 = 0.20M

<em>The total ion concentrations of the solutions A is greater than that of solution B. Therefore, there is a net flow of water molecules towards A. </em>

3)  Solution A: 0.10M CaCl2 Solution B: 0.50M KCl

Calculate the concentration of ions in solutions A and B using,

Total ion concentration =  M o l a r i t y  ×  N umber o f  i ons

Solution A:  Total ion concentration =  0.10 ×  3 = 0.30M

Solution B:   0.50 ×  2 = 1.0M

<em>The total ion concentrations of the solutions B is greater than that of solution A. Therefore, there is a net flow of water molecules towards B. </em>

5 0
3 years ago
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