Answer: The tree died 9709.46 years before.
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant = 100
a - x = amount left after decay process = [tex]\frac{30}{100}\times 100=30[/tex]
a) to find rate constant
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{5600years}=1.24\times 10^{-4}years^{-1}[/tex]
b) to know the age
[tex]t=\frac{2.303}{1.24\times 10^{-4}}\log\frac{100}{30}[/tex]
[tex]t=9709.46years[/tex]
The tree died 9709.46 years before.
The _______ biome is the largest on Earth.
Explanation:
taiga the largest land well forest
If an electrical current can run though a solution, it is said to contain what?
Answer:
electrolytes
Explanation:
If an electrical current can run though a solution, it is said to contain ions and the solution in which ions are present is called as electrolytes.
What are ions?
An ion is defined as an atom or a molecule which has a net electrical charge. There are 2 types of ions :1) cation 2) anion . The cation is the positively charged ion and anion is the negatively charged ion . As they are oppositely charged they attract each resulting in the formation of ionic bond.
Ions consisting of single atom are mono-atomic ions while which consists of two or more ions are called as poly-atomic ions . They are created by chemical interactions . They are very reactive in their gaseous state and rapidly react with oppositely charged ions resulting in neutral molecules.
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Find the density of an object that has a mass of 12.69 grams and a volume of 3.5cm3
Answer:
3.62 g/cm³
Explanation:
density = mass ÷ volume
Therefore, do 12.69 divided by 3.5
Which Chemical Reaction is balanced?
Answer:
A
Explanation:
The letter A is the correct answer
What is the concentration if 20 grams of NaOH was dissolved in enough water to make a 250 mL NaOH solution?
Answer: 1 molar NaOH contains 40 grams of NaOH per every liter of water
Explanation:
so 2 M NaOH contains twice that amount, ie. 80 grams per liter. Then, ine 250 ml of weater, there should be 80/4 = 20 grams of solid NaOH dissolved.
Ideal gas law:
If 6.3 moles of a gas in a 20 L cylinder have a pressure of 5.5 atm, what is the temperature?
Answer:
212. 9 degree celcius
Explanation:
From PV =nRT
T= PV/nR
T= (5. 5x20)/(6. 3x0. 082)
T= 110/0. 5166
T= 212. 9 degree celcius
A buffer solution is prepared by adding NaH2PO4
to a solution of H3PO4 (phosphoric acid).
H3PO4(aq) = H+ (aq) + H2PO4 - (aq)
What happens if HCl is added?
In the case when the HCI should be added so it should be shifted to reactants.
What is a buffer solution?It is the solution that should be considered as the aqueous solution that comprise of the mixture of the weak acid and the conjugate base.
Here the ph level should be change very less at the time when the small amount of the strong acid should be added.
Therefore, it should be shifted to reactants.
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B.Use the words inside the box to complete the chart below
Answer:
Answered below
Explanation:
>> ice is solid
>> water is liquid
>> Steam is gas
>> Ice → water = melting
>> water → steam = evaporation
>> steam → water = condensation
>> water → ice = freezing
how many protons are in phosphorous
Answer:
There are 15 protons in phosphorous.
~Hoped this helped~
~Brainiliest?~
What is the velocity of a wave with a frequency of 10 Hz and a wavelength of
2 m?
A. 0.2 m/s
B. 20 m/s
C. 5 m/s
D. 8 m/s
SUBMIT
Answer:
B. 20m/s
Explanation:
The wavelength of a wave can be calculated using the formula;
λ = v/f
Where;
λ = wavelength (m)
v = velocity (m/s)
f = frequency (Hz)
According to the information provided in this question; the wave has a wavelength (λ) of 2m and a frequency (f) of 10Hz.
Using λ = v/f
v = λ × f
v = 2 × 10
v = 20m/s.
40 points. Explain how a substituted hydrocarbon is made.
Answer: Organic acids form when a carboxyl group (−COOH) is substituted for one of the hydrogen atoms in a hydrocarbon.
Which factor is included in the ideal gas law that isn't present in the others?
Number of moles
Explanation:
From the general formula of ideal gas equation it is seen that number of moles is present and absent in other gas equations
The chemical name for CU3N2 is?
A) Copper (I) nitride
B) Copper nitride
C) Copper (II) nitride
D) Copper (I) nitride
Determined from the sum of potential and kinetic energy in a substance
A. Heat
B. Potential energy
C. Thermal energy
D. Total internal energy
E. Kinetic energy
C3H8 + 5O2 → 3CO2 + 4H2O
Cassandra calculated a percent yield of 75% for grams of water produced. The theoretical yield for water is 8.2 grams. How many grams of water did Cassandra actually produce during the lab?
a)9.0 grams
b)6.2 grams
c)8.2 grams
d)10.9 grams
Answer:
b)6.2 grams
Explanation:
Recall that percentage yield =
actual yield/theoretical yield * 100/1
theoretical yield = 8.2 grams
percentage yield = 75%
Let the actual yield be x
Hence;
75 = x/8.2 * 100
75 = 100x/8.2
75 * 8.2 = 100x
x = 75 * 8.2/100
x = 6.15 g
x = 6.2 g
75 =
what’s the answer to number 6 ty!!
Answer:
0.00032 M
Explanation:
From the question,
Applying the for pH
pH = -log[H⁺]............... Equation 1
Where H⁺ = Hydrogen ion concentration of Hydrochloric acid
Given: pH = 3.50
Substitute into equation 1 and solve for H⁺
3.50 = -log[H⁺]
Taking the log inverse of both side,
H⁺ = 10⁻⁽³⁵/¹⁰⁾
H⁺ = 0.00032 M
Hence the H⁺ of Hydrochloric acid is 0.00032 M
an elephant puts a force of 30,000 N on its four feet,
which have a total area of 7,500 cm². What is the pressure
it puts on the ground
Explanation:
pressure is Force/area
30000/0.75
your friend says that there is a kind of fue that only dries when it is exposed to a special type of light.can light cause glue to dry?
Answer:
No. Light is not a physical thing, so it cannot change physical things like glue.
Explanation:
Light is not effective at all to glue, it doesn't do anything at all.
Fungus on the crops can be controlled by using
Answer:
Explanation:
Fungicides are agents that are used to prevent or eradicate fungal infections from plants or seeds.
Answer:
Fungus on the crops can be controlled by using:-
Start by planting healthy stock.
Choose planting sites based on plant needs.
Avoid overhead watering.
Water early in the day.
Don't crowd plants.
Don't work a wet garden.
Treat with a trusted, proven fungicide.
Explanation:
hope it helps!
:)
Im Stuck on this question for My Science homework
Answer:
it's not clear
Explanation:
.
how does farming affect or change Earth systems? Give at least 3 examples.
Answer:
1.Exhaust from farming machines pollutes the air
2.Cows give off methane gas that gets into the atmosphere
3.The land the farm was cleared away on effects other recosystems
Explanation:
Farming adversely affected the earth systems such as climate change, deforestation, biodiversity loss, irrigation problems, pollutants, soil degradation, and waste production.
How does farming affect or change Earth systems?Agriculture causes a number larger of environmental issues that cause environmental degradation such as climate change, deforestation, biodiversity loss, irrigation problems, pollutants, soil degradation, and waste production.
For example, exhaust from farming machines pollutes the air, Cows give off methane gas that gets into the atmosphere and the land the farm was cleared away on effects other ecosystems.
So we can conclude that farming adversely affected the earth systems such as climate change, deforestation, biodiversity loss, irrigation problems, pollutants, soil degradation, and waste production.
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One molecule of a compound weighs 2.93 10–22 g. The molar mass of this compound is:
A)
2.06 g/mol
B)
567 g/mol
C)
168 g/mol
D)
176 g/mol
E)
none of these
Answer:
176 g/mol
Explanation:
To get this, multiply the weight of the molecule by Avogadro's number:
(2.93×[tex]10^{-22}[/tex]) × (6.022×[tex]10^{23}[/tex]) = 176.44 g/mol
Lower the Room temp. to -10.0 °C, wait until all the water has frozen, and then wait a little while more. What happens to the ice temperature after all the water is frozen?
No link or Files Plzz
Answer:
the ice becomes -20 degrees celcius colder
Explanation:
What are cells made of?
Answer: All cells are made from the same major classes of organic molecules: nucleic acids, proteins, carbohydrates, and lipids.
Explanation: please mark as brainliest
Describe the two methods to increase the rate at which a substance dissolves.
- A closed container has a volume of 10 ml and a pressure inside of 20 P. If the
container is shrunk to 3 ml, what is the new pressure?
Answer: The new pressure is 66.66 mL.
Explanation:
Given : [tex]V_{1}[/tex] = 10 mL, [tex]V_{2}[/tex] = 3 mL
[tex]P_{1}[/tex] = 20 atm, [tex]P_{2} = ?[/tex]
Formula used to calculate the new pressure is as follows.
[tex]P_{1}V_{1} = P_{2}V_{2}[/tex]
Substitute the given values into above formula as follows.
[tex]P_{1}V_{1} = P_{2}V_{2}\\20 atm \times 10 mL = P_{2} \times 3 mL\\P_{2} = \frac{20 atm \times 10 mL}{3 mL}\\= 66.66 mL[/tex]
Thus, we can conclude that the new pressure is 66.66 mL.
How many moles of mercury are equivalent to 3.46 x 1023 atoms?
Answer:
3.02 X1023 atoms Ag limol. - - 0.50 1 moles. 6.02241023 atoms.
You’re going on a plane from Alaska to Florida and you’re taking your bike. It’s the middle of the winter. You fill up your tires before you leave to a pressure of 4.72 atm on a day that is -3.50°C. When you arrive in FL at 42°C, you check the pressure in your tires before you ride and find the pressure to be:
Answer:
5.52atm
Explanation:
Using the pressure law formula:
P1/T1 = P2/T2
Where;
P1 = initial pressure (atm)
P2 = final pressure (atm)
T1 = initial temperature (K)
T2 = final temperature (K)
According to the question, the following information were provided;
P1 = 4.72 atm
P2 = ?
T1 = -3.50°C = -3.50 + 273 = 269.5K
T2 = 42°C = 42 + 273 = 315K
Using P1/T1 = P2/T2
4.72/269.5 = P2/315
CROSS MULTIPLY
4.72 × 315 = 269.5 × P2
1,486.8 = 269.5P2
P2 = 1,486.8 ÷ 269.5
P2 = 5.52atm
How many atoms are in 25.00 g of B?
A. 1.393 x 10^24 atoms of B
B. 1.333 x 10^23 atoms of B
C. 2.16 x 10^26 atoms of B
D.217 x 10^24 atoms of B
Thanks for all the efforts :)
Answer:
There are 1.393 x 10²⁴ atoms in 25.00 g of B.
Explanation:
Hey there!
We are given a value, in grams, that we need to convert to a number of atoms.
We can convert grams to atoms by using Avogadro's Number ([tex]N_A[/tex]). This number is equivalent to [tex]6.022 \times 10^{23}[/tex].
This number can be used to convert any values to:
atomsmoleculesformula unitsmolesIn order to do this problem, we will need to use dimensional analysis (DA). This process allows us to convert from grams to atoms.
We need to set up our ratios in order to work this out. We can use a periodic table to help us through this next part of the problem.
1. Locating the number of moles of B in the sample
We first need to find the amount of moles of boron (B) there are in the sample.
Checking a periodic table, the atomic mass in atomic mass units (amu) is 10.81 amu.
Atomic mass units can easily be converted to grams and these units can be used interchangeably.Therefore, for each atom of boron, it weighs 10.81 grams to us. This is equivalent to the mass of one mole of boron.
To find the number of moles, we have two possible ratios we can use:
[tex]\displaystyle \frac{1 \ mole \ B}{10.81 \ grams \ B}[/tex][tex]\displaystyle \frac{10.81 \ grams \ B}{1 \ mole \ B}[/tex]These ratios mean the same thing, but we need to convert our final unit to moles.
We are given a sample in grams, and when dividing our units, we need to keep moles.
Since the first portion of our expression is in grams, we need to have grams in the bottom of our expression.
[tex]\displaystyle 25.00 \ \text{grams B} \ \times \frac{1 \text{mole B}}{10.81 \ \text{grams B}}[/tex]We can now simplify the expression. Our grams B unit will cancel out, so we are therefore left with moles B remaining.
2. Locating the number of atoms in the sample
Now with our equation, we can convert our number of moles that would be solved if we stopped with the above. However, we need to convert to atoms.
We use Avogadro's number and create a ratio with that of moles.
[tex]\displaystyle \frac{6.022 \times 10^{23}\text{atoms}}{1 \text{mole B}}[/tex][tex]\displaystyle \frac{1 \text{mole B}}{6.022 \times 10^{23} \text{atoms}}[/tex]We need to cancel out our moles and end with atoms, so we must have moles in the denominator. Therefore, we use the first ratio.
Using our previous expression, we multiply by this new ratio and solve the expression.
[tex]\displaystyle 25.00 \ \text{grams B} \ \times \frac{1 \text{mole B}}{10.81 \ \text{grams B}} \ \times \frac{6.022 \times 10^{23}\text{atoms}}{1 \text{mole B}}[/tex]This expression can now be operated. You will need a calculator to perform this calculation.
Our numerator is:
[tex][(25.00 \times 1 \times (6.022 \times 10^{23})][/tex]Plugging this into a calculator, we get:
[tex]1.5055 \times 10^{25}[/tex]Our denominator is:
[tex](1 \times 10.81 \times 1)[/tex]This simplifies to:
[tex]10.81[/tex]Dividing our numerator and denominator:
[tex]\displaystyle \frac{1.5055 \times 10^{25}}{10.81}[/tex]Plugging this into a calculator, we get:
[tex]1.392691952 \times 10^{24}[/tex]3. Simplifying with significant figures
Now, we need to take into account that we have significant figures. We are given this original value:
[tex]25.00[/tex]This value has four significant figures, which means we need to round our value we received above to four significant figures.
[tex]\approx 1.393[/tex]Our units are added as well as our scientific notation:
[tex]1.393 \times 10^{24} \ \text{atoms of B}[/tex]Therefore, our final answer is choice A.
The volume of 3.2 moles of nitrogen gas inside a canister is 1.5L. The canister
volume is reduced to 0.3L. How many moles of nitrogen were released?
Answer:
2.56 moles of nitrogen was released.
Explanation:
We'll begin by calculating the final moles of nitrogen in the canister. This can be obtained as follow:
Initial mole (n₁) = 3.2 moles
Initial volume (V₁) = 1.5 L
Final volume (V₂) = 0.3 L
Final mole (n₂) =?
V₁/n₁ = V₂/n₂
1.5 / 3.2 = 0.3 / n₂
Cross multiply
1.5 × n₂ = 3.2 × 0.3
1.5 × n₂ = 0.96
Divide both side by 1.5
n₂ = 0.96 / 1.5
n₂ = 0.64 mole
Finally, we shall determine the number of mole of nitrogen that was released. This can be obtained as follow:
Initial mole (n₁) = 3.2 moles
Final mole (n₂) = 0.64 mole
Amount released =?
Amount released = n₁ – n₂
Amount released = 3.2 – 0.64
Amount released = 2.56 moles
Thus, 2.56 moles of nitrogen were released.