Moles He = 7.83 x 10^24 / 6.02 x 10^23 =13.0
<span>mass He = 13.0 mol x 4.00 g/mol = 52.0 g</span>
Answer:
Increasing atomic number - True
Explanation:
The modern table is based on Mendeleev’s table, except the modern table arranges the elements by increasing atomic number instead of atomic mass.
The Atomic number is the number of protons in an atom, and this number is unique for each element. For example, Hydrogen has an atomic number of 1, Calcium has an atomic number of 20.
In the modern periodic table the elements are further arranged into:
- rows, called periods, in order of increasing atomic number. Elements in the same periods have the same number of shells.
- vertical columns, called groups, where the elements have similar properties. Elements in the same group has the same number of valency (outermost number of electrons)
Answer:
40% of the energy release by the peanut is 3500 calories
Explanation:
One calorie is defined as the amount of energy required to increase the temperature of one gram of water for one degree Celsius (or one Kelvin)
Equation for energy gain by water is
Q = mcΔT
where, m is the mass of the object
c is the specific heat capacity
ΔT is the change in temperature
c = 1.0 cal/g?°C.
m = 50 g
ΔT = 50°C - 22°C
= 28°C
Q = (50)× (1)× (28)
= 1400calories
The peanut contain 1400calories of energy .
amount that 40% of energy is released to water ,
so,
Q = 1400 calories / 0.4
= 3500 calories
Therefore, 40% of the energy release by the peanut is 3500 calories
Answer:
The molarity of a solution is 2.5 M
Explanation:
Molarity is a concentration unit that describes how much of a solution is dissolved in solution.
Molarity of a solution can found by using the formula,
Molarity (M) = (moles of solute)/(Liters of Solution).
Given, mass of Sodium = 114.95 grams.
Volume of water = 2 L.
Here, Sodium is solute as it is dissolved in water, which is the solvent.
Moles of Sodium(solute) can be found by using the formula,
Number of Moles = mass/Molecular weight.
mass of Sodium = 114.95 grams.
Molecular weight = 22.989 grams
Number of Moles of Sodium(solute) =114.95/22.989 = 5.
Substituting the values in the formula, we get,
M = 5/2 = 2.5 M
