Answer:
Volume
Explanation:
Density:
Density is equal to the mass of substance divided by its volume. In order to find the density of earth when mass is given we have to calculate its volume. The volume of earth is calculated by using the volume formula for sphere. i.e 4/3 π r³. we also require radius to find the volume and we know that
Diameter = 2 × radius
The diameter of earth equator is 12756.75 Km. So we calculate the radius by dividing the diameter by 2. Then by putting the value of radius in 4/3 π r³ we will get the volume and then we can calculate the density of earth.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Symbol:
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
1016)(2.2<span> × </span>1010<span>) = A × </span>10B<span> A= B= Chemistry.</span>
Answer:
11.31g NaClO₂
Explanation:
<em> Is given 250mL of a 1.60M chlorous acid HClO2 solution. Ka is 1.110x10⁻². What mass of NaClO₂ should the student dissolve in the HClO2 solution to turn it into a buffer with pH =1.45? </em>
It is possible to answer this question using Henderson-Hasselbalch equation:
pH = pKa + log₁₀ [A⁻] / [HA]
<em>Where pKa is -log Ka = 1.9547; [A⁻] is the concentration of the conjugate base (NaClO₂), [HA] the concentration of the weak acid</em>
You can change the concentration of the substance if you write the moles of the substances:
[Moles HClO₂] = 250mL = 0.25L×(1.60mol /L) = <em>0.40 moles HClO₂</em>
Replacing in H-H expression, as the pH you want is 1.45:
1.45 = 1.9547 + log₁₀ [Moles NaClO₂] / [0.40 moles HClO₂]
-0.5047 = log₁₀ [Moles NaClO₂] / [0.40 moles HClO₂]
<em>0.3128 = </em>[Moles NaClO₂] / [0.40 moles HClO₂]
0.1251 = Moles NaClO₂
As molar mass of NaClO₂ is 90.44g/mol, mass of 0.1251 moles of NaClO₂ is:
0.1251 moles NaClO₂ ₓ (90.44g / mol) =
<h3>11.31g NaClO₂</h3>
Answer:
The correct answer is 1.21 L.
Explanation:
Based on the given information, the reaction will be,
CS2 (l) + 3Cl2 (g) ⇒ CCl4 (l) + S2Cl2 (l)
By using the standard values of the substances, the standard enthalpy of the reaction is,
ΔH° = [(-139.5) + (-58.5) – 0 – (87.3)] kJ/mol
= -285.3 kJ/mol
The amount of heat evolved for 3 moles of chlorine reacted us 285.3 kJ.
Now the number of moles of chlorine needed to react to produce 5.00 kJ is,
= 5.00 kJ × 3 mol Cl2/285.3 kJ
= 0.0526 mol Cl2
Now the volume of chlorine gas at 27degree C and 812 mmHg will be,
Volume = 0.0526 mol Cl2 × 0.0821 Latm/mol K × 300 K/ 1.07 atm
= 1.21 L
