Answer:
The answer is "[tex]1.4 \ \bold{ billion-years}[/tex]".
Explanation:
Using formula:
[tex]\to N_{Now} = N_{orige}e^{\lambda t} \\\\[/tex]
[tex]\to[/tex] 1 U atom produces 1 Pb atom after decay.
[tex]\to[/tex] U's original numbers are now the sum of U counts and Pb counts.
[tex]\to N_U=(N_U+N_{pb})e^{\lambda Ut}[/tex]
[tex]\to 1 = (1+3) \ exp[(\frac{-\ln(2)}{t_{(half)}} \times t ]\\\\\to t = [\frac{\ln(4)}{\ln(2)}] \times t_{(half)}[/tex]
[tex]= 14 \times 10^8 \ \ years\\\\=1.4 \ billion \ \ years[/tex]
Write a net ionic equation for the reaction that occurs when aqueous solutions of nitric acid and sodium hydroxide are combined.
Be sure to specify states such as (aq) or (s).
Answer:
H^+(aq) + OH^-(aq) -------> H2O(l)
Explanation:
We must first write the molecular reaction equation as follows;
HNO3(aq) + NaOH(aq) ------>NaNO3(aq) + H2O(l)
The complete ionic equation is;
H^+(aq) + NO3^-(aq) + Na^+(aq) + OH^-(aq) -------> Na^+(aq) + NO3^-(aq) + H2O(l)
The net ionic equation therefore is;
H^+(aq) + OH^-(aq) -------> H2O(l)
How many molecules are there in 6.73 moles of phosphorus trichloride? (write your answer in scientific notation).
Answer: There are [tex]4.05\times 10^{24}[/tex] molecules in 6.73 moles of phosphorus trichloride
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
1 mole of [tex]PCl_3[/tex] contains = [tex]6.023\times 10^{23}[/tex] molecules
Thus 6.73 moles of [tex]PCl_3[/tex] contains = [tex]\frac{6.023\times 10^{23}}{1}\times 6.73=4.05\times 10^{24}[/tex] molecules
Thus there are [tex]4.05\times 10^{24}[/tex] molecules in 6.73 moles of phosphorus trichloride
The attraction between water molecules and a Nation or a Clion occurs because water molecules are —
A.
nonpolar
B
symmetrical.
С
polar.
D
linear.
Answer:
answer is
c. Polar
hope this helps
number 3 ...................
Which phrase best describes an individual organ
Answer:
the answer is B
Explanation:
When elements bond together they use energy in the bonding process.
What is this energy process called?
Answer:
chemical energy
Explanation:
This energy process is called exothermic when the reactants are at a higher energy level as compared to the products while it is an endothermic process if the reactant require energy to form products.
What is the process of bonding ?The covalent bonds that bring atoms together in the form of molecules store potential energy. This is commonly referred to as chemical energy.
When two different elements bond together to form compounds , the covalent bonds initial present are broken and new bonds are formed .
The energy level of the new formed compound will be lower than the individual atom as the difference in energy level of both the elements is released as heat.
This energy process is called exothermic when the reactants are at a higher energy level as compared to the products while it is an endothermic process if the reactant require energy to form products.
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1. Which functional group is found in an ester? (1 point)
Answer:
2nd one
Explanation:
Fact!
any force that causes an object to move in a circle is called
Answer: Any force that causes an object to move in a circle is called centripetal force.
A gas has three initial measurements: temperature 306 K, pressure 740 mm Hg, and volume 36 mL. The gas's temperature is increased to 850 K while its pressure is increased to 1750 mm Hg. What is the new volume of the gas in mL?
Answer:
The new volume of the gas is 42.28 mL.
Explanation:
Gay Lussac's law indicates that when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, the pressure of the gas decreases. This law can be expressed mathematically as follows:
[tex]\frac{P}{T}=k[/tex]
where k = Constant
Boyle's law says that "The volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure." This law is expressed mathematically as:
P * V = k
Finally, Charles's Law indicates that as the temperature increases, the volume of the gas increases and as the temperature decreases, the volume of the gas decreases. In summary, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:
[tex]\frac{V}{T}=k[/tex]
Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:
[tex]\frac{P*V}{T}=k[/tex]
Studying an initial state 1 and a final state 2, it is satisfied:
[tex]\frac{P1*V1}{T1}=\frac{P2*V2}{T2}[/tex]
In this case:
P1= 740 mmHgV1= 36 mLT1= 306 KP2= 1750 mmHgV2= ?T2= 850 KReplacing:
[tex]\frac{740 mmHg*36 mL}{306 K}=\frac{1750 mmHg*V2}{850 K}[/tex]
Solving:
[tex]V2=\frac{850 K}{1750 mmHg} *\frac{740 mmHg*36 mL}{306 K}[/tex]
V2= 42.28 mL
The new volume of the gas is 42.28 mL.
How many mL are in 5.000 L
Answer:
Start off and multiply the volume value by 1000,
so that would mean
5000 x 1000
= 5,000,000 mL
What structural units make up ionic solids?
O A. Molecules
B. Nonmetal atoms
O C. Metal atoms
O D. lons
The option that is the structural units that make up ionic solids is option D. Ions
What are ionic solids?Ionic solids are made up of ions, which are atoms or groups of atoms that have a positive or negative charge due to the gain or loss of electrons. In ionic solids, the positive ions (cations) are typically formed by metal atoms, while the negative ions (anions) are typically formed by nonmetal atoms. The ions in ionic solids are held together by electrostatic forces of attraction, called ionic bonds.
Therefore, These bonds are formed when the electrons from the outermost energy level of the metal atom are transferred to the outermost energy level of the nonmetal atom, creating a stable compound.
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9.) How many grams of phosphorus can be recovered
from 245.0 g triphosphorus pentanitride?
a.) 139.7 g
b.) 105.3 g
c.) 57.01 g
According to stoichiometry as 162.955 g of phosphorous pentanitride has 92.919 g of phosphorous , thus 245 g of phosphorous pentanitride will have 139.7 grams of phosphorous.
What is stoichiometry?Stoichiometry is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.
Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.It is important as it helps the chemical reactions to obey law of conservation of mass.
As 162.955 g of phosphorous pentanitride=92.919 g of phosphorous
∴ 245 g of phosphorous pentanitride =245×92.919/162.955=139.702 g.
Thus, 139.702 g of phosphorus can be recovered from 245.0 g triphosphorus pentanitride.
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The boiling process is considered to be____
your answer is D. physical change, because a new substance is not formed.
The boiling process is considered to be a physical change as no new substance is formed.
What is a physical change?Physical changes are defined as changes which affect only the form of a substance but not it's chemical composition. They are used to separate mixtures in to chemical components but cannot be used to separate compounds to simpler compounds.
Physical changes are always reversible using physical means and involve a change in the physical properties.Examples of physical changes include melting,boiling , change in texture, size,color,volume and density.Magnetism, crystallization, formation of alloys are all reversible and hence physical changes.
They involve only rearrangement of atoms and are often characterized to be changes which are reversible.
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Please help me pretty please
Answer:
The answer would probably be C. The clock can be seen and heard.
What causes the expression of a recessive trait? one dominant and one recessive factor (allele) one dominant gene two recessive factors (alleles) two dominant factors (alleles)
Answer: i think it’s two recessive alleles
Explanation:
Answer:Two recessive alleles is correct
Explanation:
I TOOK THE TEST (k-12 student) TwT
help please. its over dilutions in chemistry
Answer:
The molarity of the solution is given as 0.15 M. This means that it contains 0.15 moles of NaOH in 1 liter of solution.
hope this helps you☺️☺️
Your friend says, “chemical changes are caused by an input in energy. In physical changes, there is no transfer of energy” is your friend correct? Why or why not?
Answer: Your friend is incorrect.
Explanation: If we have an object or something that isn’t moving, (let’s say a notebook on a desk). If there is change, and the notebook moves, there is acceleration. Force = Mass times acceleration, f = m*a. There has to be a force, first of all. If you touched the notebook and moved it, some of your energy is transferred and now the notebook has kinetic energy. If our system is you and the notebook, the total energy doesn’t change. the energy is transferred, but doesn’t change. Your friend is not correct. Please give brainliest hope this helped!
5 - What is the pH of a solution with a
pOH of
8.6? What are the [+] and [OH']
concentrations?
Answer:
the pH solution is 4.9.
[[tex]H^{+}[/tex](aq)] = [tex]10^{-pH}[/tex]
Explanation:
What is the temperature?
Answer:
17.25 degrees
Explanation:
....but I cannot tell you if that is °C or °F <===== that is left out of the question.
Help me pretty please
Answer:
I think it is D
Explanation:
How many molecules are in 8.2 moles of water,H2o
Answer:
4.938×10^24 molecules
Explanation:
a mole is 6.023×10^23
(8.2)×(6.023×10^23)=4.938×10^24
Which one is it? It’s in my science class and i have no idea
Answer:
More energy then closer electrons.
Explanation:
As electrons move away from the nucleus, their energy increases.
State two methods to increase the rate of the chemical reaction and explain
for each, in terms of particle behavior, how each method would increase
reaction rate.
METHOD 1:
Explanation:
METHOD 2:
Explanation:
Answer:
METHOD 1: (surface area of a solid reactant) METHOD 2: (concentration or pressure of a reactant)
Explanation:
METHOD 1: (surface area of a solid reactant) Increasing the surface area of a solid reactant exposes more of its particles to attack. This results in an increased chance of collisions between reactant particles, so there are more collisions in any given time and the rate of reaction increases.
METHOD 2: (concentration or pressure of a reactant) Increasing the concentration means that we have more particles in the same volume of solution. This increases the chance of collisions between reactant particles, resulting in more collisions in any given time and a faster reaction. As we increase the pressure of reacting gases, we increase the rate of reaction.
The actual value for absolute zero in degrees Celsius is −273.15. Use the formula below to determine your percent error for both gas samples.
|experimental value – actual value| x 100
actual value
Please just tell me how to find the experimental value
Answer:
As you noticed, the percent-error formula needs you to use a value in the ... The actual absolute zero is 275C below my coldest recorded value. ... The only way your calculations makes sense is you're trying to calculate how ... Next, I'll interpret "I found that AZ is at -258°C" as "I calculated AZ to be 260 degrees below 2°C".
Explanation:
The experimental error will be 8.95%
Calculating percentage error.The formula used for calculating the percentage error is expressed as:
[tex]\% error=\frac{|exp. \ value - actual \ value|}{actual \ value} \times 100[/tex]
Given the following parameters
Actual value = −273.15 degrees Celcius
Let the experimental value be 300 degrees Celcius (since we are not given)
[tex]\% error=\frac{|300 - 273.15|}{300} \times 100\\\% error=\frac{|26.85|}{300} \times 100\\\% error=8.95\%[/tex]
Hence the experimental error will be 8.95%
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A sample of unknown gas has a temperature of 378k. When the temperature is increased to 546k,the volume also increases to 1047 ml. What was the original volume ?
Given :
A sample of unknown gas has a temperature of 378 K.
[tex]T_i = 378 \ K , \ T_f = 546 \ K[/tex]
When the temperature is increased to 546 K, the volume also increases to 1047 ml.
[tex]V_f - V_i = 1047 \ ml[/tex]
Solution :
We know, temperature is directly proportional to volume.
[tex]\dfrac{T_i}{T_f}=\dfrac{V_i}{V_f}\\\\\dfrac{T_i}{T_f} = \dfrac{V_i}{1047 + V_i}\\\\\dfrac{V_i}{1047+V_i}=\dfrac{378}{546}\\\\546V_i = 378V_i + 378\times 1047\\\\168V_i = 3,95,766\\\\V_i = 2,355.75\ ml[/tex]
Therefore, the original volume is 2.355.75 ml.
Colour of crushed chalk + Iodine solution
Hey guys so my cuz gave me this stone when he went to mexico
can u plz tell me what kind of stone this is?
Answer:
pretty sure that's an old jolly rancher
Under which condition will the atmospheric pressure be greater. When the air is cold, or when the air is warm
If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.
3. ________________ If you increase the force on an object, its acceleration increases.
4. ________________ If you increase the mass of an object, its acceleration decreases.
5. ________________ To accelerate a 3 kg skateboard at 9 m/s 2 , a force of 3 newtons is needed.
6. ________________ The amount of inertia an object has depends on its speed.
Answer:
3 - True
4 - True
5 - False
6 - False
which properties should Beryllium (Be) have?
A. Liquid
B. Low melting point
C. Shiny
D. Poor conductor