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Sliva [168]
3 years ago
7

A new penny has a mass of 2.49 g and a volume of 0.349 cm3. Is the penny made of pure copper?

Chemistry
1 answer:
velikii [3]3 years ago
7 0
Yes it is. Copper is the same mass and volume. Plus all pennies are made of copper
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Use the drop-down menus to identify the experimental group with additional nutrients and the control group without additional nu
Paladinen [302]

Answer:

A. 1 to 16

B. 17 to 32

Explanation:

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3 years ago
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The normal boiling point of methanol is 64.7∘c and the molar enthalpy of vaporization of 71.8kj/mol. the value of δs when 1.11 m
maxonik [38]
The answer is 236.5 J/K

According to Δ G formula:

ΔG = ΔH - TΔS

when ΔG is the change in free energy (KJ)

and ΔH is the change in enthalpy (KJ)= ΔHvap * moles

                                                              = 71.8 KJ/mol * 1.11 mol
                                                             
                                                              =   79.7 KJ

and T is the absolute temperature (K)= 64 °C + 273°C = 337 K

Δ S is the change in entropy  KJ/K

by substitution:

when at equilibrium ΔG = 0 

∴ΔS = ΔH / T

       =79.7 KJ/ 337 K

     = 0.2365 KJ/K

     = 236.5 J/K


6 0
3 years ago
If a buffer solution is 0.190 m in a weak acid (ka = 8.2 × 10-5) and 0.590 m in its conjugate base, what is the ph?\
Lubov Fominskaja [6]
<span>You use the Henderson - Hasselbalch equation pH = pKa + log ([salt]/[acid]) pKa = -log (8.2*10^-5) = 4.081 pH = 4.081 + (0.590/0.190) pH = 4.081 + log 3.105 pH = 4.081 + 0.49206 pH = 4.573</span>
5 0
3 years ago
Please give me the reasons of the solution!
irinina [24]

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As a polymer becomes more crystalline,

its melting point doesn't decreases, its density doesn't decreases, its stiffness doesn't decreases and its yield stress doesn't decreases.

2. The answer is option B, that is the molecules are arranged in sheets, with their long axes parallel and their ends aligned as well.

In the smectic A liquid-crystalline phase, molecules are arranged in sheets, with their long axes parallel and their ends aligned as well.

3.  For a substitutional alloy to form, the two metals combined must have similar atomic radii and chemical bonding properties.

6 0
3 years ago
2 H2 + O2= 2 H2O
AVprozaik [17]

Answer:

the answer is 4.0moles

Explanation:

1mole of O2 produce 2moles of H2O/x mole will produce 8.0moles of H2O then the answer is 4.0moles.

3 0
3 years ago
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