Which sentence from "Black Hole Beginnings" contains a cause-and-effect relationship?
More matter mounts up on the outside, increasing the pressure on the inside.
Instead it is a dramatic melding, or blending, of atoms, called nuclear fusion.
Each atom has its own tiny center, or nucleus.
Surrounding each nucleus is an electrical force field..
Pb + Mg(NO₃)₂ → Pb(NO₃)₂ + Mg
This reaction would NOT occur because Pb is less reactive than Mg and as such Pb cannot displace the Mg in order for the reaction to occur under normal conditions.
Mg + Fe(NO₃)₂ → Fe + Mg(NO₃)₂
This reaction would occur. This is because Mg is more reactive than Fe and as such can displace it in the reaction, thus allowing the reaction to occur under normal conditions.
Cu + Mg(NO₃)₂ → Cu(NO₃)₂ + Mg
This reaction would NOT occur. Mg is more reactive than Cu, and as such copper cannot displace magnesium in order for the reaction to occur under normal conditions.
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Answer:</h3>
4.227 × 10^-19 Joules
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Explanation:</h3>
Energy of a photon of light is calculated by the formula;
E = hf, where h is the plank's constant, 6.626 × 10^-34 J-s and f is the frequency.
But, f = c/λ
Where, c is the speed of light (2.998 × 10⁸ m/s), and λ is the wavelength.
Given the wavelength is 470 nm or 4.7 × 10^-7 m
Therefore;
E = hc/λ
= (6.626 × 10^-34 J-s × 2.998 × 10^8 m/s) ÷ 4.7 × 10^-7 m
= 4.227 × 10^-19 Joules
Therefore, the energy of a photon with 470 nm is 4.227 × 10^-19 Joules
5.75g
Explanation:
Given parameters:
Number of atoms = 1.505 x 10²³atoms
let us find the number of moles and mass of this atom.
Solution:
The mole is convenient unit for reporting measurements in chemistry. It allows us to make mathematical calculations:
one mole of substance contains 6.02 x 10²³atoms
Number of moles of Na given = 
= 0.25moles
Mass of Na atom given = number of moles x molar mass
Molar mass of Na= 23g/mole
Mass of Na = 0.25 x 23 = 5.75g
learn more:
Number of moles brainly.com/question/1841136
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