Answer:
whats your question
Explanation:
2055 Q. No. 10^-2
mole of KOH is dissolved in 10 litres of
water. What will be the pH of the solution?
12
Ans: pH = 11
Answer:
11
Explanation:
Moles of KOH = [tex]10^{-2}[/tex]
Volume of water = 10 liters
Concentration of KOH is given by
[tex][KOH]=\dfrac{10^{-2}}{10}\\\Rightarrow [KOH]=10^{-3}\ \text{M}[/tex]
[tex][KOH][/tex] is strong base so we have the following relation
[tex][KOH]=[OH^{-}]=10^{-3}\ \text{M}[/tex]
[tex]pOH=-\log [OH^{-}]=-\log10^{-3}[/tex]
[tex]\Rightarrow pH=14-3=11[/tex]
So, pH of the solution is 11
The density of gold is 19.3 g/cm³. Which of the following shows the mass of a gold bar that is 4.50 cm × 8.00 cm × 20.00 cm?
Answer:
13896g
Explanation:
volume = 4.50×8.00×20.00 = 720 cm³
mass = density × volume
mass= 19.3 × 720 = 13896g
Please help me ASAP I’ll mark Brainly
Answer:
Batteries hold chemical energy
Explanation:
The battery acid in a battery leads to chemical energy.
In a lab, you produce a quantity of the radioactive isotope thorium-234. Over the course of several weeks, the unstable isotope decays, and you measure the amount of thorium-234 remaining in the sample. You obtain the following data. What is the half life of Thorium-234? How much Thorium 234 will there be after two half lives?
Days Elapsed Grams of Thorium 234 Remaining
0 16
12 11
24 8
36 6
a. 36 days
b. 12 days
c. 24 days / 4 grams
Answer:
Option C. 24 days / 4 grams
Explanation:
From the question given above, the following data were obtained:
Days Elapsed >>>> Mass Remaining
0 >>>>>>>>>>>>>>> 16
12 >>>>>>>>>>>>>>> 11
24 >>>>>>>>>>>>>>> 8
36 >>>>>>>>>>>>>>> 6
A. Determination of the half-life of Thorium-234.
To determine the half-life, it is important to know the definition of half life.
Half-life is defined as the time taken for a substance to reduce to half its original mass.
From the table given above, we can see that the original mass of the isotope is 16 g (i.e at 0 day). By day 24, the mass of the isotope is 8 g (i.e half the original mass). Thus, the half-life of the isotope is 24 days.
B. Determination of the mass of the isotope remaining after 2 half lives.
Original amount (N₀) = 16 g
Number of half-lives (n) = 2
Amount remaining (N) =?
N = 1/2ⁿ × N₀
N = 1/2² × 16
N = 1/4 × 16
N = 4 g
Thus, 4 g of the isotope is remaining after 2 half lives.
Summay:
Half-life = 24 days
Amount remaining after 2 half-lives = 4 g
Option C gives the correct answer to the question.
Element X has two naturally occurring isotopes, 65X (isotopic mass 65.0457 amu, abundance 20.53%) and 67X (isotopic mass 66.9704 amu, abundance 79.47%). Calculate the atomic mass of element X.
Answer:
66.5753 amu
Explanation:
From the question given above, the following data were obtained:
Isotope A (⁶⁵X):
Mass of A = 65.0457 amu
Abundance of A = 20.53%
Isotope B (⁶⁷X):
Mass of B = 66.9704 amu
Abundance of B = 79.47%
Atomic mass of X =?
The atomic mass of X can be obtained as follow:
Atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100]
= [(65.0457 × 20.53)/100] + [(66.9704 × 79.47)/100]
= 13.3539 + 53.2214
= 66.5753 amu
Therefore, the atomic mass of X is 66.5753 amu.
Element X, with an atomic mass of 66.58 amu, has 2 naturally occurring isotopes, ⁶⁵X (65.0457 amu, 20.53%) and ⁶⁷X (66.9704 amu, 79.47%).
What is the average atomic mass?The average atomic mass (atomic mass) of an element is the sum of the masses of its isotopes, each multiplied by its natural abundance.
Element X has 2 isotopes:
⁶⁵X with an isotopic mass of 65.0457 amu and an abundance of 20.53% (0.2053).⁶⁷X with an isotopic mass of 66.9704 amu and an abundance of 79.47% (0.7947).We can calculate the average atomic mass of X using the following expression.
mX = m⁶⁵X × ab⁶⁵X + m⁶⁷X × ab⁶⁷X
mX = 65.0457 amu × 0.2053 + 66.9704 amu × 0.7947
mX = 66.58 amu
Element X, with an atomic mass of 66.58 amu, has 2 naturally occurring isotopes, ⁶⁵X (65.0457 amu, 20.53%) and ⁶⁷X (66.9704 amu, 79.47%).
Learn more about atomic mass here: https://brainly.com/question/6200158
Nitrogen can exist as a solid, a liquid, or a gas. Which of the following lists the
phases of nitrogen in order of increasing density?
1. liquid, gas, solid
2. gas, liquid, solid
3. gas, solid, liquid
4. solid, liquid, gas
The phases of nitrogen in order of increasing density is solid, liquid, and gas.
Nitrogen is known to be odorless and colorless. Nitrogen makes up about 78% of the gases that we've in the atmosphere. It has an atomic number of 7 and is represented with the symbol N.It should be noted that nitrogen can be a solid, a liquid or a gas. When nitrogen is at ordinary pressure, it is known to be a gas. In a case whereby nitrogen is below 77°K, then it's a liquid and it's a solid when it's below 63°K.The density explains the mass per unit volume that nitrogen has when it's either at gaseous, solid or liquid state. It should be noted that the highest density is at its gaseous state.Therefore, the phases of nitrogen in order of increasing density will then be solid, liquid, and gas.In conclusion, the correct option is D.
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