Answer is: beryllium-10.
The diagram shows that atom has 4 protons, 5 neutrons and 2 valence electrons.
Atomic number is the number of protons, which is characteristic of a chemical element, beryllium (Be) is an element with atomic number 4.
Two valence electrons means that atom is from 2. group of periodic table, only beryllium is from that group; sodium (1. group), boron (13. group) and carbon (14. group).
Beryllium-10 has 6 neutrons, so it is isotope (different number of neutrons or mass number).
Answer:
The correct answer is 160.37 KJ/mol.
Explanation:
To find the activation energy in the given case, there is a need to use the Arrhenius equation, which is,
k = Ae^-Ea/RT
k1 = Ae^-Ea/RT1 and k2 = Ae^-Ea/RT2
k2/k1 = e^-Ea/R (1/T2-1/T1)
ln(k2/k1) = Ea/R (1/T1-1/T2)
The values of rate constant k1 and k2 are 3.61 * 10^-15 s^-1 and 8.66 * 10^-7 s^-1.
The temperatures T1 and T2 are 298 K and 425 K respectively.
Now by filling the values we get:
ln (8.66*10^-7/3.61*10^-15) = Ea/R (1/298-1/425)
19.29 = Ea/R * 0.001
Ea = 160.37 KJ/mol
Answer: There would have to be three nitrogen atoms in the products. The law of conservation of matter states that the amount of substance before a reaction occurs should be the same as the amount of substance after the reaction.
Explanation: This is the EXACT sample answer from the test, just reword it if you want. ^
Answer:
- NaClO₃ > KBr > KNO₃ > NaCl.
Explanation:
The attached file contains the graph with the solubility curves for the four substances, KNO₃, NaClO₃, KBr, NaCl.
To determine the solubility of each salt at a certain temperature, you read the temperature on the horizontal axis, labeled Temperature (ºC), and move upward up to intersecting the curve of the corresponding salt. Then, move horizontally up to insersceting the vertical axis, labeled Solubility (g/100g of H₂O), to read the solubility.
The higher the reading on the vertical axis, the higher the solubility.
The red vertical line that I added is at a temperature of 40ºC.
The number in blue indicate the order in which the solubility curves are intersected at that temperature:
- 4: NaCl: this is the lowest solubility
- 3: KNO₃: this is the second lowest solubility
- 2: KBr: this is the third lowest solubility
- 1: NaClO₃: this is the highest solubility.
Thus, the rank, from most soluble to least soluble is:
- NaClO₃ > KBr > KNO₃ > NaCl.
True. Our earth Is getting hotter due to global warming.
