A sample taken from a layer of mica In a canyon has 2.10 grams of potassium-40. A test reveals it to be 2.6 billion years old. How much potassium-40 was in the sample originally if the half-life of potassium-40 is 1.3 billion years? A. 4.20 g B. 8.40 g C. 12.6 g D. 16.8 g the E. 25.2 g ​

Answers

Answer 1

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option b) is correct answer.

A Sample Taken From A Layer Of Mica In A Canyon Has 2.10 Grams Of Potassium-40. A Test Reveals It To
A Sample Taken From A Layer Of Mica In A Canyon Has 2.10 Grams Of Potassium-40. A Test Reveals It To

Related Questions

A galaxy that has an undefined shape is best classified as a(n)
galaxy.

Answers

Answer:

irregular galaxy

pls give brainliest :)

Answer:

irregular galaxy

it is undefined shape

Which is the formula mass of (NH4)2SO4?
96.07 amu
114.12 amu
116.17 amu
132.17 amu

Answers

Answer:

132.17amu

Explanation:

(14.01+1.01 multiplied by 4)=18.05×2=36.1

36.1+32.07= 68.17

16.00×4=64

68.17+64=132.17

Answer:

132.17 amu

Explanation:

just took the test. got 100

What is the percent yield of a reaction?
O A. The difference between measured and calculated amounts
OB.
The amount of produd obtained
amount possible
* 100
C. The amount of product actually obtained in a reaction
D. The amount of product that is possible from a reaction

Answers

Answer:

B. The amount of produd obtained/amount possible * 100

Explanation:

In chemistry, the yield of a chemical reaction is the quantity or amount of products obtained in that chemical reaction. It is calculated by using the following formula:

Percentage yield = Actual yield/theoretical yield × 100

- The actual yield is the amount of products got from a chemical reaction

- The theoretical yield is the amount of product got from using the balanced equation (stoichiometry).

What is the change in enthalpy of the first reaction below, given the enthalpies of the other two reactions?

Here's the reactions:

There was a formatting issue with the specific chemistry symbols, there all correct in the picture below

2C(s) + O2(g) → 2CO(g)


C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol



CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol


There was a formatting issue with the specific chemistry symbols, there all correct in the picture below

Answers

Answer:

∆H0 = -222kJ/mol

Explanation:

Using Hess's law, we can find the ΔH of a reaction from the sum of another related reactions as follows:

Using the reactions:

(1) C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol

(2) CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol

Twice (1):

2C(s) + 2O2(g) → 2CO2(g) ∆H0= 2*-394 KJ/mol = -788kJ/mol

The inverse reaction of (2):

-(2) CO2(g) → CO(g) + 1/2 O2(g) ∆H0= 283 KJ/mol

Twice this reaction:

2*-(2) 2CO2(g) → 2CO(s) + O2(g) ∆H0= 2*283 KJ/mol= 566kJ/mol

Now, the sum of 2*(1) - 2*(2) produce:

2C(s) + 2O2(g) + 2CO2(g)→ 2CO2(g) + 2CO(g) + O2(g) ∆H0= -788kJ/mol +  566kJ/mol

Subtracting the molecules that ar in both sides of the reaction:

2C(s) + O2(g) → 2CO(g) ∆H0 = -222kJ/mol

mendeleev's periodic table is studied even though it is considered to be defective​

Answers

Answer:

This is because Mendeleev arranged the elements in order of increasing relative atomic mass.

Explanation:

Dmitri Mendeleev is one of the scientists that contributed to the development of periodic table in chemistry. He was able to organise elements into rows according to their atomic mass and into columns based on chemical and physical properties. This is the main reason why his periodic table is still studied even though it has some defects which include:

--> Grouping of elements that are not similar chemically: For example Copper and Silver bear no resemblance with the alkali metals, but they have been placed together in the first group.

--> Position of isotopes: According to his periodic table: Isotopes of an element must be given separate places in the periodic table because they have different atomic masses.

--> Electronic arrangement of elements: It failed to explain the electronic arrangement of elements.

--> Separation of chemically similar elements:

Elements that are chemically similar such as Gold and Platinum have been placed in separate groups.

CH3 CH2 CH2 OH + H2SO4
Get the product and answer the following questions :

I. A + HCl
II. A --> Combustion ( what product does it form. Write out the equation )
III.A ---> Hydrogenation (what product does it form. Write out the equation )



Note : A represents the product gotten from the reaction between
CH3 CH2 CH2 OH and H2SO4​

Answers

Answer:

propene and hydrogen is product

When propanol is heated with concentrated sulphuric acid at 443 K, dehydration takes place and prop-1-ene is formed. In this reaction concentrated sulphuric acid acts as a dehydrating agent.

I. A + HCl gives )-gives 2-chloropropane

II. A --> Combustion ( what product does it form. Write out the equation propene ozonide

III.A ---> Hydrogenation (what product does it form. Write out the equation )propanol

Please hurry this is due tomorrow morning

A student is studying the ways different elements are similar to one another. Diagrams of
atoms from four different elements are shown below.

Which two atoms are of elements in the same group in the periodic table?

F Atom 1 and Atom 2
G Atom 1 and Atom 4
H Atom 2 and Atom 3
J Atom 3 and Atom 4

Answers

Answer: G Atom 1 and Atom 4.. hope this helps and good luck!

what is the molarity of HCL solution that has a density of 1.17g/ml at 25°?​

Answers

~Solution :-

Here, we have been given that;

$ \bf{1 ml}$ = 1.17 g$ \bf{1 l}$ = 1170 g

Hence, we can note that,

No. of moles of HCL (n) = $ \sf{\frac{1170}{36.5}}$

(n) = 32.05

[tex] \\ [/tex]

Thus,

Molarity = 32.05 mg/L

Hence, molarity of the given solution will be 32.05 mg/L.

For a reaction: aA → Products, [A]o -4.3 M, and the first two half-lives are 56 and 28 minutes, respectively. Calculate k (without units). Show Work!

A. 7.7 x 10^-2
B. 4.2 x 10^-3
C. 3.8 x 10^-2
D. 8.3 x 10^-3
E. None of these​

Answers

Answer:

C.[tex]3.8\times 10^{-2}[/tex]

Explanation:

We are given that

Initial concentration, [tex][A]_o=4.3 M[/tex]

First half life, [tex]t_{\frac{1}{2}}=56[/tex]minutes

Second half life, [tex]t'_{\frac{1}{2}}=28[/tex]minutes

We have to find K.

The given reaction is zero order reaction.

We know that for zero order reaction

[tex]t_{\frac{1}{2}}=\frac{[A]_o}{2k}[/tex]

Using the formula

[tex]56=\frac{4.3}{2k}[/tex]

[tex]k=\frac{4.3}{2\times 56}[/tex]

[tex]k=3.8\times 10^{-2}[/tex]

Hence, option C is correct.

Zero-order reactions are the reactions when a surface or a catalyst is required for the reaction to proceed and is saturated by the reactant chemicals. The result of the concentration versus the time plot will be a straight line in a zero-order reaction.

[tex]3.8 \times 10 ^{-2}[/tex] is the value of k.

How to calculate the value of k?

Given,

Initial concentration [tex][A_{0}][/tex] = 4.3 MThe first half-life of the reactant [tex](t \dfrac{1}{2})[/tex] = 56 minutesThe second half-life of the reactant [tex](t \dfrac{1}{2})[/tex]  = 28 minutes

The given reaction in the question is of zero-order and for that, we know that,

[tex]t \dfrac{1}{2} = \dfrac{[A_{0}] }{2\;\rm k}[/tex]

Substituting the values in the equation we get:

[tex]\begin{aligned}56 &= \dfrac{4.3 }{2\; \rm k}\\\\\rm k &= {4.3 }{2 \times 56}\\\\\rm k &= 3.8 \times 10^{ -2}\end{aligned}[/tex]

Therefore, option C is correct.

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Help me please

The options are
A. Translation
B. Rotation
C. Enlargement
D.reduction

Answers

this is enlargement since the new image has been enlarged twice the size of the original.

translation means it has moved
rotation means it turned another way
reduction means it got smaller

Answer:

C. Enlargement

Explanation:

can u plz solve it n send the answer​

Answers

1. Cl2 + H2O → HOCl + HCl

2. Tooth decay starts when when the pH of the mouth is lower than 5.5. Tooth enamel is made up of calcium phosphate and it is one of the hardest substances of the body. But it is corroded when the pH is less than 5.5. The bacteria of our mouth produce acids by degradation of sugar and food particles remaining in our mouth after eating food.

3. Fluorine salts are added in toothpaste to protect our teeth from tooth decay. Fluorine salts are mildly basic, so they neutrelise the acid in our mouth that leads to tooth decay.

4. Tincture of iodine is iodine, pottasium iodide and sodium iodide dissolved in ethanol. Iodine acts in an antiseptic manner by destroying microbial proteins and DNA.

5. Tincture of iodine is clear and reddish brown liquid.

While studying bacterial cells, scientists measure the lengths of the cells in one colony. The chart shows their data. The scientists notice that one measurement stands out. How should the scientists best deal with this measurement?

Answers

Answer:

The scientists should best deal with this measurement by stating that there was an error during measuring and collect further data.

HELP ME ASAPPPP PLZZZZZ!!!!!
For the reaction C + 2H2 → CH4, how many grams of hydrogen are required to produce 16.8 moles of methane, CH4 ?

Answers

The answer is going to be 2.40g

Name the following bases.
Fe(OH)3
- iron(III) hydroxide
- iron(II) hydroxide
- iron hydroxide

Answers

Answer:

1

Explanation:

Ferric Hydroxide

3. 1

Fe. (OH)

Fe(OH)3

Answer:

iron(III) hydroxide

Explanation:

I just took the quiz!

when carbon is heated in a limited supply of oxygen, a gas is obtained.
1 .what is the name of this gas​

Answers

Answer:

carbon monoxide

I think its correct but I am not sure

Answer: when carbon is heated in air carbon dioxide is formed, so is incomplete combustion which results in carbon monoxide.

Explanation: but when carbon dioxide reacts with more oxygen carbon monoxide is formed i guess.

I AM A BIT SURE BUT HOPE THIS HELPSSSS!!!!

how do i calculate the concentration of a certain solution​

Answers

Answer:

Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.

The intermediate product formed during the production of urea is,

Answers

Answer:

Arginine is intermediate product formed during the production of urea

The key combination is ornithine, on which the urea molecule is 'created'; intermediates in the procedure contain citrulline and arginine.

What is the Production of Urea?

The urea cycle is a procedure of conversion of toxic ammonia to negligibly toxic urea. Consequences of the urea cycle are 1 molecule of urea, 2 molecules of ADP, and 1 molecule of both AMP and fumaric acid.

When Ammonia and carbon dioxide recovery During urea decomposition a mixture of gaseous carbon dioxide and also ammonia is accumulated and also immersed into a dilute aqueous urea resolution.

Find more information about Production of Urea here:

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Analysis of an ore of calcium shows that it contains 13.61 g calcium and 21.77 g oxygen in a 46.28-g sample. Calculate the percent composition of this compound.

Answers

Answer:

29.41% of Calcium and 47.04% of Oxygen

Explanation:

The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.

The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:

13.61g / 46.28g * 100 = 29.41% of Calcium

And percent composition of Oxygen is:

21.77g / 46.28g * 100 = 47.04% of Oxygen

why is it important of having regular supervision of the market?

Answers

Supervision of weights and measures promotes accurate measurements of goods and services to ensure that everybody gets a fair trade in the marketplace. Not so coincidentally it also is a deterrent to ensure that traders are being honest in their trade practises.

Which is a mixture?
Sodium metal
chlonne gas
sodium metal and chlonne gas
sodium chlonde (salt) and water

Answers

Answer:

I believe it's salt and water

Explanation:

not sure

Answer:

Mixture is a electronic device used to peel the things such as onion ,tomato,ginger, garlic etc.

Sodium and chlorine combine to form table salt.
2Na(s) + Cl2(g) → 2NaCl(s)
Does this reaction obey the law of conservation of mass?

Answers

Answer:

yes it does

Explanation:

because the ratios on the reactants and products are equal

The reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.

Yes, this reaction obeys the law of conservation of mass. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; it is only rearranged.

In the given reaction, we have 2 sodium atoms (Na) on the left side and 2 sodium atoms (Na) on the right side. Similarly, we have 2 chlorine molecules (Cl₂) on the left side and 2 chlorine atoms (Cl) on the right side. Therefore, the number of atoms of each element is balanced on both sides of the reaction.

Additionally, the total mass of the reactants (2Na + Cl₂) is equal to the total mass of the product (2NaCl). The coefficients in the balanced equation represent the stoichiometric ratios, ensuring that the mass is conserved.

Hence, the reaction 2Na(s) + Cl₂(g) → 2NaCl(s) obeys the law of conservation of mass.

Learn more about law of conservation of mass from the link given below.

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BJECTIVE TYPE QUESTIONS
Fill in the blank spaces by choosing the correct words from the words given in list.
List : composition, heat, chemical, photosynthesis, physical
1. Heating of zinc oxide is a
change.
2. Burning of coal is a
change.
3. There is a change in state and
during a chemical change.
4. Plants make their food by the process of
5.
energy is generally given out or absorbed during a chemical change​

Answers

Answer:

1.Physical change

2. Chemical change

3. Heat

4.photosynthesis

5. composition

Name five metal which are both dilute and memorable? class 10​

Answers

Iron, magnesium, zinc, aluminum. I don’t know of any others

2. Nitric oxide contains 46.66% nitrogen and 53.34% oxygen. Water contains 11.21% hydrogen and 88.79% oxygen. Ammonia contains 17.78% hydroger and 82.22% nitrogen. Use these data to verify the law of reciprocal proportions. ​

Answers

Answer:

The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other

The compounds formed includes;

1) Nitric oxide, NO

Nitrogen = 46.66% × 30.01 = 14

Oxygen = 53.34% × 30.01 = 16

2) Water, H₂O

Hydrogen = 11.21% × 18.01528 = 2

Oxygen = 88.79% × 18.01528 ≈ 16

3) Ammonia, NH₃

Hydrogen = 17.78% × 17.031 ≈ 3

Nitrogen = 82.22% × 17.031 ≈ 14

The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8

The ratio of nitrogen to hydrogen in ammonia = 14:3

The ratio in which hydrogen and oxygen combine with nitrogen = 3/16

The ratio of hydrogen and oxygen combine with each other in water = 2/16

Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions

Explanation:

Over a period of 2 minutes, 180 coulombs of charge pass through a resistor. What is the current through the resistor during this time?
Type the correct answer in the box. Use numerals instead of words.
The current through the resistor during this time is

A.

Answers

Answer:

Explanation:

Formula

The current = charge / time

The charge is in coulombs

The time has to be in seconds.

1 minute = 60 seconds

2 minutes = 120 seconds.

charge = 180 coulombs

current = 180 / 120

current = 1.5 amperes.

To begin the experiment, Xavier washed his hands and put on safety goggles. He then measured 120 milliliters of tap water, 2.5 milliliters of baking soda, and 2.5 milliliters of citric acid. The initial temperature of the water was 23.5°C.


Next Xavier added the baking soda and citric acid to the water. The mixture immediately began to bubble vigorously, which lasted for about 30 seconds. The new temperature of the mixture was 17.7°C.

Is a chemical reaction taking place during Xavier’s experiment? How do you know?



WILL GIVE BRAINLIEST!!!!!!!!!!!!!!!

Answers

Answer:

Yes a chemical reaction is taking place.

Explanation:

There is a change in temperature along with bubbling. All signs of a chemical reaction.

Yes a chemical reaction is taking place. Temperature changes are signs of chemical reactions. Bubbling also shows chemical reactions as new substances are being created.

The graph shows the change in concentration of one of the species in the reaction
A + B + C→D.

If the graph indicates the reaction rate, then the concentration of which species is plotted?

A

B

C

D

Answers

Answer:

its D

Explanation:

Took the test

The specie whose concentration is plotted is D. The rate of reaction is how quickly or slowly hat a reaction proceeds.

Rate of  reaction

The term rate of reaction refers to how quickly or slowly hat a reaction proceeds. A reaction rate plot involves the concentration of the species plotted against time.

Now we can see from the plot that concentration is increasing with time. Since the concentration of products increases with time, then the specie whose concentration is plotted is D.

Learn more about rate of reaction: https://brainly.com/question/11256472

“during times of personal crisis we may feel the need to engage the services of a therapist to help us with out problems”

fact or opinion and why

Answers

Answer:

That is a fact.

Explanation:

A therapist can help support you going forward and when in a personal crisis.

A therapist can help us mentally during a personal crisis. This is a fact. because there are personal therapist who helps us to recover from negative thoughts and mental illness.

What is psychotherapy?

Individual psychotherapy is the use of psychological techniques to address emotional and personality issues or disorders. In other words, there are treatments that assist in treating emotional disorders in a manner similar to how a doctor would treat a fever or cold.

Milder emotional conflicts to serious psychopathologies might all be a part of these issues. As a result, both those who are depressed and those who are having marital problems can seek counselling.

The problems  that can be healed through psychotherapy include difficulties coping with stressors , trauma and related experiences,   mental illnesses such as depression, anxiety an so on.

Find more on psychotherapy:

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______ exhibits the highest
intermolecular forces of the states of matter.

A. Solid

B. Liquid

C. Gas

D. Vacuum

Answers

I would say A) solid

Element 'X' forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of the periodic table as:

I) Si
2) Al
3) Mg
4) Na



pls pls answer fast ​

Answers

Answer:

Mg

Explanation:

Mg forms 2+ ions and mgcl2 has a melting point over 700°C I believe.

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