Answer:
False
Explanation:
Magnesium is the element of second group and third period. The electronic configuration of magnesium is - 2, 8, 2 or
There are 2 valence electrons of magnesium.
Only the valence electrons are shown by dots in the Lewis structure.
As, stated above, there are only two valence electrons of magnesium, so in the Lewis structure, two dots are made around the magnesium symbol.
Given that the electronic configuration is:- .
Orbital s cannot accommodate 3 electrons and also in magnesium it has . Hence, the statement is false.
Volcanic ash insulates the earth
Volcanic ash is hot
Volcanic eruptions cause the average temperature to increase
Answer: The mole fraction of calcium chloride and water in the solution is 0.057 and 0.943 respectively
Explanation:
We are given:
Molality of calcium chloride = 3.35 m
This means that 3.35 moles of calcium chloride are present in 1 kg or 1000 g of water
To calculate the number of moles, we use the equation:
Given mass of water = 1000 g
Molar mass of water = 18.02 g/mol
Putting values in above equation, we get:
Total moles of solution = [3.35 + 55.49] = 58.84 moles
Mole fraction of a substance is given by:
Hence, the mole fraction of calcium chloride and water in the solution is 0.057 and 0.943 respectively
Answer:
49.3% water
Explanation:
Answer:
the initial temperature of the iron sample is Ti = 90,36 °C
Explanation:
Assuming the calorimeter has no heat loss to the surroundings:
Q w + Q iron = 0
Also when the T stops changing means an equilibrium has been reached and therefore, in that moment, the temperature of the water is the same that the iron ( final temperature of water= final temperature of iron = T )
Assuming Q= m*c*( T- Tir)
mc*cc*(T-Tc)+mir*cir*(T - Tir) = 0
Tir = 20.3 °C + 300 g * 4.186 J/g°C * (20.3 C - 19 °C) / ( 51.9 g * 0.449 J/g°C )
Tir = 90.36 °C
Note :
- The specific heat capacity of water is assumed 1 cal/g°C = 4.186 J/g°C
- We assume no reaction between iron and water
To calculate the initial temperature of the iron sample, use the equation q = m * c * T, where q is the heat absorbed or released, m is the mass of the substance, c is the specific heat capacity, and T is the change in temperature which is 90.36 °C
To calculate the initial temperature of the iron sample, we can use the equation:
q = m * c * T
Where q is the heat absorbed or released, m is the mass of the substance, c is the specific heat capacity, andT is the change in temperature. In this case, we know the mass of the iron sample, the specific heat capacity of iron, and the change in temperature of the water. By rearranging the equation, we can solve for the initial temperature of the iron sample.
Thus,
Tir = 20.3 °C + 300 g * 4.186 J/g°C * (20.3 C - 19 °C) / ( 51.9 g * 0.449 J/g°C )
Tir = 90.36 °C
#SPJ12
Answer:
K₂O
Explanation:
Given parameters:
Mass of K = 36.7g
Mass of O = 7.51g
Unknown:
Empirical formula of the compound
Solution:
The empirical formula of a compound is it's simplest ratio by which the elements in the compound combines. It differs from the molecular formula that shows the actual atomic ratios.
To find the empirical formula, follow this process;
Elements K O
Mass 36.7 7.51
Molar
mass 39 16
Number of
moles 36.7/39 7.51/16
0.94 0.47
Divide by
the smallest 0.94/0.47 0.47/0.47
2 1
Empirical formula is K₂O
The empirical formula of the compound composed of 36.7 g of potassium and 7.51 g of oxygen is K2O.
To determine the empirical formula of a compound, we need to find the ratio of the elements present. In this case, we have 36.7 g of potassium and 7.51 g of oxygen. To find the ratio, we need to convert these masses to moles by dividing them by the molar masses of potassium and oxygen. The molar mass of potassium is 39.10 g/mol and the molar mass of oxygen is 16.00 g/mol. Dividing the masses by the molar masses gives us 0.939 mol potassium and 0.469 mol oxygen. The ratio between these two elements is approximately 2:1, so the empirical formula of the compound is K2O.
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The number of protons neutrons, and electrons in each of the following species given are below;
The total number of protons present in an atom is known as the atomic number of that atom. The atomic number has no correlation either with the number of neutrons or the number of electrons present inside an atom.
15N7 ⇒ 7 electrons, 8 neutrons, 7 protons
33S16 ⇒ 16 protons, 16 electrons, 17 neutrons
63Cu29 ⇒ 29 electrons, 34 neutrons,29 protons
84Sr38 ⇒ 38 electrons, 46 neutrons,38 protons
130Ba56 ⇒ 56 electrons, 74 neutrons,56 protons
186W74⇒ 74 electrons, 112 neutrons,74 protons
202Hg80 ⇒ 80 electrons, 122 neutrons ,80 protons
To learn more about the atomic number from here, refer to the link ;
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Answer:
1. 7 protons, 7 electrons, 8 neutrons
2. 16 protons, 16 electrons, 17 neutrons
3. 29 protons, 29 electrons, 34 neutrons
4. 38 protons, 38 electrons, 46 neutrons
5. 56 protons, 56 electrons, 74 neutrons
6. 74 protons, 74 electrons, 112 neutrons
7. 80 protons, 80 electrons, 122 neutrons