Answer:
Explanation:
Significant figure implies number of digits that are to be considered. Some rules are required to be considered when writing a given expression to an expected significant figures.
So that:
1) 0.00004050 is 4 significant figures
2) 54.7000 is 6 significant figures
3) 1,000.09 is 6 significant figures
4) 0.039 is 2 significant figures
The Lewis structure/diagram for CH2O (aka Formaldehyde) can be written in either of the following ways shown in the picture.
The dots represent electrons in the valence shell of the atom (the outermost shell). The green dots are electrons that belong to the Oxygen atom, the blue belong to the Carbon atom, and the pink belong to the Hydrogen atoms.
Covalent bonds are bonds between atoms where atoms share electrons with each other. Atoms bond because they obey the octet rule ( the rule states that most atoms of main-group elements tend to want 8 electrons in their valence shells).
Oxygen has 6 valence electrons, Carbon has 4, and Hydrogen has 1. H does not follow the octet rule, but C and O do, so the atoms are arranged in this way so that the O and C atoms have a full octet of electrons in their valence.
The mass of glycerol to that would need to be combusted to heat 500.0g of water from 20.0°C to 100.0°C is; 9.32 grams.
We must establish the fact that energy is neither created nor destroyed.
Therefore, the amount of heat absorbed by water is equal to the amount of heat released by the combustion of glycerol.
Total heat absorbed by water, H(water) is;
Q(water) = m C (T2 - T1)
Q(water) = 500 × 4.184 × (100-20)
Q(water) = 167.36 kJ
Consequently, the quantity of heat evolved by the combustion of glycerol is;
Q(glycerol) = 167,360 J = n × ΔH°comb
where, n = no. of moles of glycerol.
167.36 kJ= n × 1654 kJ/mole
n = 167.36/1654
n = 0.1012 moles of glycerol.
Therefore, mass of glycerol combusted, m is;
m = n × Molar mass
m = 0.1012 × 92.09
m = 9.32 g.
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Answer:
The value of Kp at this temperature is 7.44*10⁻³
Explanation:
Chemical equilibrium is established when there are two opposite reactions that take place simultaneously at the same speed.
For the general chemical equation for a homogeneous gas phase system:
aA + bB ⇔ cC + dD
where a, b, c and d are the stoichiometric coefficients of compounds A, B, C and D, the equilibrium constant Kp is determined by the following expression:

Where Px is the partial pressure of each of the components once equilibrium has been reached and they are expressed in atmospheres. The equilibrium constant Kp depends solely on temperature and is dimensionless.
In the case of the reaction:
2 HI (g) ⇔ H₂ (g) + I₂ (g)
the equilibrium constant Kp is determined by the following expression:

The system comes to equilibrium at 425 °C, and
- PHI = 0.794 atm
- PH2 = 0.0685 atm
- PI2 = 0.0685 atm
Replacing:

Kp=7.44*10⁻³
<u><em>The value of Kp at this temperature is 7.44*10⁻³</em></u>
Answer: 94.13 L
Explanation: In STP in an ideal gas there is a standard value for both temperature and pressure. At STP,pressure is equal to 1atm and the temperature at 0°C is equal to 273.15K. This problem is an ideal gas so we use PV=nRT where R is a constant R= 0.08205 L.atm/mol.K.
To find volume, derive the equation, it becomes V=nRT/P. Substitute the values. V= 4.20 mol( 0.08205L.atm/mol.K)(273.15K) / 1 atm = 94.13 L. The mole units, atm and K will be cancelled out and L will be the remaining unit which is for volume.