Answer:
V equals four-thirds times pi times r cubed
Explanation:
Volume = a³ , where a is length of each side. Volume = l × w × h , where l is length, w is width and h is height. Volume = 4/3 πr³ , where r is the radius. Volume = πr²h , where r is the radius and h is the height.
Answer:
At 0.58 L of 0.540 M NaOH solution contain 12.5 g NaOH.
Explanation:
Given data:
At volume = ?
Mass of NaOH = 12.5 g
Molarity of solution = 0.540 M
Solution:
First of all we will calculate the number of moles of sodium hydroxide.
Number of moles = mass/molar mass
Number of moles = 12.5 g / 40 g/mol
Number of moles = 0.3125 mol
Volume of NaOH:
Molarity = number of moles / volume in L
Now we will put the values.
0.540 M = 0.3125 mol / volume in L
volume in L = 0.3125 mol / 0.540 mol/L
volume in L = 0.58 L
Answer:
Increase in CO2 (g) over time.
No NaHCO3 (s) will be left after a time
Explanation:
The reaction, shown below;
2NaHCO3(s) → Na2CO3(s)+CO2(g)+H2O(ℓ) is a decomposition reaction. A decomposition reaction is a kind of chemical reaction in which a given chemical specie breaks up to give other chemical species. Decomposition may be induced by heat or light.
Usually, there is only one reactant in a decomposition reaction; the specie that disintegrates into the products. This reactant usually decreases in concentration steadily because it is converted into products. This is why the mass of NaHCO3(s) in the system continues to decrease steadily until it finally falls to zero.
Conversely, the concentration (for aqueous) or volume (for gases) or mass (for solid) products of the reaction increases steadily as the reaction progresses. This explains why the volume of CO2 in the system will steadily increase over time.
Based on exposure time and place, the Sun's radiation may have harmful or beneficial effects.
<h3>What is solar radiation?</h3>
Solar radiation refers to the radiation from the Sun in the form heat, light and other forms of radiation.
The radiation from the Sun may have harmful or beneficial effects.
The effects of the Sun's radiation can be classified as BE, HE or SP as follows:
- BE- UV rays can help treat some health conditions. It creates Vitamin D
- SP- Use sunblock lotion with SPF 15 during hot days.
- BE- With the presence of sunlight, farmers can dry their crops.
- HE- UV rays can damage the tissue in your eyes.
- BE- Research says that sunlight helps moods.
- HE- Too much exposure from the sun can cause skin cancer.
- SP- Use sunglasses when you stay under the sun.
- SP- Wear a wide- brimmed hat on sunny days.
- BE- Humans can do recreational activities on a sunny day.
- SP- Wear sunglasses that filter UV light.
- HE- Prolonged exposure to the sun’s heat makes your skin age faster than normal.
- HE- Too much heat from the sun can cause heat stroke and loss of water.
- BE- Sunlight helps strengthen your immune system.
- BE- The vitamin D made thanks to the sun plays a big role in bone health.
- SP- Avoid sun in the middle of the day, from about 10 a.m. to 3 p.m.
Learn more about Sun's radiation at: brainly.com/question/921530
#SPJ1
Answer:
The enthalpy of the nitrogen-nitrogen bond in N2H4 is 162.6 kJ
Explanation:
For the reaction: N2H4(g)+H2(g)→2NH3(g), the enthalpy change of reaction is
ΔH rxn = 2 ΔHºf NH3 - ΔHºf N2H4
but we also know that the ΔH rxn is calculated by accounting the sum of number of bonds formed and bonds broken as follows:
ΔH rxn = 6H (N-H) + 4 (N-H) + 2H (H-H)
where H is the bond enthalpy .When bonds are broken H is positive, and negative when formed, in the product there are 6 N-H bonds , and in the reactants 4 N-H and 1 H-H bonds).
Consulting an appropiate reference handbook or table the following values are used:
ΔHºf (NH3) = -46 kJ/mol
ΔHºf (N2H4) = 95.94 kJ/mol
(The enthalpy of fomation of hydrogen in its standard state is zero)
H (N-H) = 391 kJ
H (H-H) = 432 kJ
H (N-N) = ?
So plugging our values:
ΔH rxn = 2mol ( -46.0 kJ/mol) - 1mol(95.4 kJ/mol) = -187.40 kJ
-187.40 kJ = 6(-391 kJ) + 4 (391 kJ) + 432 + H(N-N)
-187.40 kJ = -350 kJ + H(N-N)
H(N-N) = 162.6 kJ
