Answer is: between the carbon atom and the oxygen atom in a molecule of methanal there are two (2) <span>pairs of electrons.
Methanal or formaldehyde (H</span>₂C=O)<span> </span><span>is the simplest of the </span><span>aldehydes.
In methanal, bond between carbon and oxygen is double covalent bond (one sigma and one pi bond), which means there are four shared electrons or two pair of electrons.</span>
M = 4 g = 4/1000 kg = 0.004 kg, θ₂ = 21.0°C, θ₁ = 0°C , c = 0.44kJ/kg°C,
Q = mc(θ₂ - θ₁)
Q = 0.004*0.440*(21 - 0)
Q = 0.03696 kJ
0.03696 kJ<span> of heat is absorbed.</span>
The energy release when dissolving 1 mol of NaOH in water is 445.1 kJ
the mass of NaOH to be dissolved is 32.0 g
The number of NaOH moles in 32.0 g - 32.0 g / 40 g/mol = 0.8 mol
the energy released whilst dissolving 1 mol of NaOH - 445.1 kJ
when dissolving 0.8 mol - the energy released is 445.1 kJ/mol x 0.8 mol
therefore heat released is - 356.08 kJ
answer is -356.08 kJ
The metal is lead, Pb.
One unit of the oxide contains one atom of O (16.00 u).
∴ Mass of oxide = 16.00 u O × (100 u MO/7.17 u O) = 223.15 u MO
Mass of M = mass of MO – mass of O = 223.15 u -16.00 u = 207.2 u
The only element with an atomic mass of 207.2 u is lead (Pb) and the formula of the oxide is PbO.
The density of an object is defined as its mass divided by its volume. Mathematically, density = Mass / Volume. The unit of density is kilogram per cubic meter, kg / m^3 or g /cm^3.
For the question given above: the
Mass = 200.0 g
Volume = 100.0 cm^3
Therefore, Density = Mass / Volume = 200 / 100 = 2
Thus, the density of the object is 2 g /cm^3.
