It’s 7.0 I just had the apex practice test
Take mass of zinc divided by the relative molecular mass - 30 for zinc ( from periodic table)
Answer:
0.023
Explanation:
The Arrhenius' equation states that:

Where k is the velocity constant of the reaction, A is the constant of the collisions, Ea is the activation energy (the energy necessary to the molecules have so the reaction will happen), R is the gas constant (8.314 J/molK) and T is the temperature.
This equation is derivated of:
k = pZf
Where
p=fraction of collisions that occur with reactant molecules properly oriented
f=fraction of collisions having energy greater than the activation energy
Z=frequency of collisions
Thus, p*Z = A, and
f = 
So, if the energy of the molecules is 12.5 kJ/mol = 12500 J/mol, thus the fraction will be:
f = 
f = 0.023
Answer: a) if a proton transforms to a neutron, a positron is produced
B) when an neutron transforms into a proton, an electron is produced
Explanation:
The both are nuclear decay processes which produce a neutrino and tremendous energy. The conversion of protons to neutrons is an energetically difficult process. However, the conversion of neutrons to electrons is commonly called beta decay in nuclear physics.
respuesta: fisico
explicacion:Un cambio químico es cuando su estructura atómico es modificada en este caso lo único que estas haciendo es pintando la camiseta en ningún momento deja de ser camiseta