Answer:
It is difficult, if not impossible, to heat a solid above its melting point because the heat that ... in a solid are packed in a regular structure that is characteristic of that particular substance.
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The element in period 4 of the Periodic Table with the highest electronegativity is krypton (2.96).
Answer:

Explanation:
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En este caso, dado que estamos tratando con problem sobre porcentaje peso/peso de hierro, arena, cobre y aluminio, primero debemos calcular la masa inicial de estos dos primeros en la mezcla original de acuerdo con:

Ahora si podemos calcular la masa de la mezcla final como la suma de las masas de todos los constituyentes de la mezcla:

Finalmente, podemos calcular los porcentajes P/P como se muestra a continuación:

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Answer:
35 mL
Explanation:
Let the amount of 75% mixture needed be A.
The amount of each solution with their respective concentration to be added together can be expressed as:
0.75A + 0.3(280)...............eqn 1
The addition of the two solution must merge with the expected concentration and this can be expressed as:
0.35(A + 280).............eqn 2
Eqn 1 must be equal to eqn 2, hence:
0.75A + 0.3(280) = 0.35(A + 280)
Solve for A.
0.75A + 84 = 0.35A + 98
0.40A = 14
A = 35
Hence, 35 mL of the 75% mixture will be needed.
The answer is latent evidence. Evidence that can't be seen by the naked eye. These are hidden pieces of evidence.This evidence needs special tools, chemicals or materials to exposed them. Such items like cyanoacrylate fumes and UV light source are used to see the finger print on a gun.