Types of radioactive decay

If sodium-24 has a half-life of 14.96 hours then rate constant K is 0.0463 hr²−1 Rounded to two significant figures, the answer is (a) 4.63 × 10²−2 hr²−1.

The first-order rate equation is given by:

ln(N_t/N_0) = -kt

where N_0 is the initial amount of the substance, N_t is the amount of substance at time t, k is the rate constant, and ln is the natural logarithm.

The half-life of sodium-24 is given as 14.96 hours, which means that after 14.96 hours, the amount of sodium-24 will be reduced to half of its initial amount. Therefore, we can write:

N_t = (1/2)N_0

Substituting this into the first-order rate equation, we get:

ln(1/2) = -k(14.96)

Solving for k, we get:

k = [ln(1/2)]/14.96

k ≈ 0.0463 hr²−1

Therefore, the rate constant for the radioactive decay of sodium-24 is approximately 0.0463 hr²−1. Rounded to two significant figures, the answer is (a) 4.63 × 10²−2 hr²−1.

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Answer:

The molar mass of atoms of an element is given by the standard relative atomic mass of the element multiplied by the molar mass constant

Explanation:

Answer:

The chemical equation when Hexane is subjected to strong heat in the absence of air

Answer:

Negative

Explanation:

Because i learned it in 5th grade

Answer:

negative

Explanation:

When you are missing an electron or two, you have a positive charge. When you have an extra electron or two, you have a negative charge.

At pOH value  of 6.0 the pH value of the following solution is 8.0 and the concentration of [\(H^{+}\) ] ion is \(10^{-8}\)

In this question we will apply the formula

      pH +pOH = 14 . . . . . . . . . . . . .(1)

where pH = concentration of [\(H^{+}\) ] ion

pOH = concentration of [\(OH^{-}\) ] ion

As per the question

pOH =6.0

Putting the value of pOH in equation (1) we get the value of pH

              pH + 6.0 =14

             pH = 14 -6.0

             pH  = 8.0

 The value of pH if the pOH value is 6.0 is 8.0

To find the concentration of \(H^{+}\) ion we will use the following formula

This is calculated by the formula

                                 [\(H^{+}\)} = \(10^{-pH}\)

where we will write the values of pH

Hence the concentration of [\(H^{+}\)} ion is \(10^{-8}\)

Therefore at  pOH of 6.0 the pH value of the following solution is 8.0 and the concentration of [\(H^{+}\) ] ion is \(10^{-8}\)

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The complete question is -

What is the pH value and concentration of [\(H^{+}\) ] ion of the following if the pOH value of the solution is 6.0 ?

Answer:

A sprinter consumes more oxygen than a marathon runner.

Explanation:

A sprinter requires big amounts of air in a short time to not get tired as fast and run faster. A marathon runner has more controlled and paced breathing so he does not get tired but can run long distances. Marathon runners also run slower than sprinters.

Answer:

coastal area with very high tides deep ocean water miles from a river's mouth

Explanation:

Marshes are a type of wetland ecosystem where water covers the ground for long periods of time. Marshes are dominated by herbaceous plants, such as grasses, reeds, and sedges(National Geographic Society).

hope dis help

Answer:

Given:

Volume of wet hydrogen gas (Vwet) = 4.00 L

Pressure (P) = 737 torr

Temperature (Twet) = 23.0°C = 296 K

To find:

Volume of dry hydrogen gas (Vdry) at STP (Tdry = 273 K and Pdry = 760 torr)

Solution:

Convert temperature to Kelvin: T = Twet = 23.0°C + 273 = 296 K

Use the combined gas law: P1V1/T1 = P2V2/T2

Plug in values: P1 = P, V1 = Vwet, T1 = T, P2 = Pdry = 760 torr, T2 = Tdry = 273 K

Solve for V2 (Vdry): Vdry = Vwet x Pdry x T / P x Tdry

Substitute values: Vdry = 4.00 L x 760 torr x 296 K / 737 torr x 273 K

Simplify: Vdry ≈ 3.48 L

Therefore, the volume of dry hydrogen gas at STP is approximately 3.48 L.

So the answer key is correct, but their method may have been incorrect.

Answer:

b I think it is the correct answer

Answer:

yes

Explanation:

Usually, it would not affect the crucible, but depending on the temperature of the flame the enamel of the crucible may begin to melt and stick to the metal object being used to handle the crucible. This tiny amount that is melted off can cause very small changes in the original mass of the crucible, which although it is almost unnoticeable it is still there. Therefore, the answer to this question would be yes.

Martensite : A Supersaturated interstitial solid solution of carbon in Alpha iron.

Marten a solid carbon interstitial solution in iron.

It is a steel metastable phase that results from austenite's transformation at temperature below 320 °C.

A body-centered tetragonal lattice characterizes martensite, an interstitial super saturated solution of carbon in iron.

It is extremely hard and brittle with a carbon concentration of up to 2%.

Its structure is acicular or needle-like and it is the result of rapid cooling (quenching).

The degree of martensitic transformation-achieved hardness is closely related to the rate of cooling and the percentage of carbon in steel.

So, Martensite is an interstitial supersaturated solid carbon solution in alpha iron.

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In the ground state, it should be noted that the the number of valence electrons the K-42 isotope has is only one valence electron.

In the first group of the periodic table is potassium. It has a valence shell with one electron.

We can assume that potassium only has one electron on its valence shell because it belongs to group 1. The isotope is irrelevant because the only distinction between isotopes is the number of neutrons present in their nuclei.

In summary, it should be noted that K-42 only possesses one valence electron.

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Two isotopes of potassium are K-37 and K-42. How many valence electrons are in an atom of K-42 in the ground state?

Answer:

true

Explanation:

hope this answer helps :)

Answer:

true

Explanation

vitamins and minerals are protective foods

Answer:

ooooooooooppppppppppppppppppppppppp

Explanation:

1.6524 has 5 SF and 4 SF after the decimal point.

5.67 has 3 SF and 2 SF after the decimal point.

First we will add the numbers and then we will round the answer to the correct number of SF.

1.6524 + 5.67 = 7.3224

5.67 has 2 SF after the decimal point and is the number with the least amount of SF after the decimal point. So we have to round the answer to the second decimal place.

Answer: 7.32

Answer:

1. yes

2. yes

3. no

sorry if I am wrong but hope this helps

Answer:

Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from oxygen molecules or nutrients into adenosine triphosphate, and then release waste products.

Explanation:

Answer:

Explanation:

1,2,4,

The equations that show combustion are equations A, B and D.

When we talk about combustion, the idea is that the substance would be burnt in oxygen. In other words, the combustion can be taken to be an oxidation reaction. It is an oxidation reaction in the sense that the oxidation number of the substance that is reacting with the oxygen would become increased.

When we look at the equations that we have, it is quite easy to pick out among the balanced reaction equations that are shown here the ones that has to do with the burning of the substance in oxygen and a consequent rise in the oxidation number.

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Answer:

Love for Music

Explanation:

This is one example of many non-physical traits. In the womb a mother can listen to her favorite music and the growing baby could grow to like it in the womb!

This is just one of the many other traits that could be passed to their offspring.

Hope this Helps!

Answer:

physical change because the gaseous water is chemically the same as the liquid

Explanation:

Matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.

Generally, matter exists in three (3) distinct or classical phases and these are; solid, liquid and gas.

A physical change can be defined as a type of change that only affects the physical form of a chemical substance (matter) without having any effect on its chemical properties. Thus, a physical change would only affect the physical appearance and properties of a chemical substance (matter) but not its chemical properties.

This ultimately implies that, a physical change result in a change of matter from one form or phase (liquid, solid or gas) to another without a corresponding change in chemical composition.

Hence, the boiling of water is considered to be a physical change because the gaseous water is chemically the same as the liquid i.e there isn't any changes in chemical composition of water when boiling.

Answer:

3. solids are measured in centimeters

4. gases And liquids are measured in milliliters

Answer:

Solids are measured in Mass

Gases and Liquids are measured in Volume

Explanation:

Solids can also additionally be measured by length as well.

fun fact: natural gas is measured by volume (cubic feet) but is sold based on its heating content (Btus). A cubic foot of natural gas is the amount of natural gas that can be contained in a cube one foot on a side, at a certain standard temperature and pressure. (source; oilgaslawyer blog)

Answer:

1, 2 and 3

Explanation:

A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons , is known as covalent bonding.

A covalent bond involves as stated above, the mutual sharing of one or more electron pairs of between two atoms. These electrons are simultaneously attracted by the two atomic nuclei. A covalent bond forms when the difference between the electronegativities of two atoms is too small for an electron transfer to occur to form ions. Shared electrons located in the space between the two nuclei are called bonding electrons. The bonded pair is the binding factor that holds the two atomic nuclei together in molecular units.

A covalent bond is commonly formed between two nonmetals. As we can see in the question; 1, 2 and 3 represents bonds formed between two nonmetallic elements. Hence they are rightly classified as molecular or covalent bonds.

Step 1 - Finding valence electrons

Let's use the first molecule, water, as an example of how to proceed to find the required properties. To find the valence electrons of each atom, we must consider their electronic configuration.

The molecule of water has O as well as H atoms. Their electronic configuration is:

Note that the valence shell is the 2nd shell for O, but the 1st shell for H. Therefore, O has 6 electrons in its valence shell, whereas H has only one.

Step 2 - Determining the Lewis structure

To determine the Lewis structure we can use a very useful tip:

The atom which makes the greatest number of bonds goes in the middle.

It's not a rule, just a tip. But it may work wonders. In the case of H2O, the atom that makes the most bonds is O, so:

Let's remember how may bonds each element makes:

The next step is a little bit like Lego playing. We must try to join the atoms together respecting the number of bonds each needs to do. For water, the only possible solution is:

Remember O has 6 electrons in its valence shell. Two of them are participating in a covalent bond, while 4 are remaining. Let's include the remaining electrons:

Step 3 - Finding the shape

To find the shape (geometry) of a molecule, we use the VSEPR (Valence Shell Electron Pair Repulsion) Theory.

Note: VSEPR states that the electrons in a covalent bond, as well as the remaining non-bonding electron pairs repulse each other. As a consequence, the molecule will adopt the geometry that minimizes the repulsion between the bonding and valence electrons.

Since water is a three atom molecule, and since there are remaining electron-pairs in the middle atom (O), its geometry will not be linear. The remaining valence electrons of O will cause the bonding electrons to "bend", i.e., to move farther away, due to repulsion. The molecule thus becomes angular:

The redox equation C6H12O6 + 6O2 -> 6H2O + 6CO2 represents the process of cellular respiration. Option C

Cellular respiration is a biochemical process that occurs in living organisms, including plants and animals, to convert organic compounds, such as glucose (C6H12O6), into usable energy in the form of adenosine triphosphate (ATP). It is the primary process by which cells derive energy to carry out their functions.

In the given equation, glucose (C6H12O6) is being oxidized, losing electrons, and releasing carbon dioxide (CO2) as a byproduct. This oxidation process results in the production of energy-rich molecules, such as ATP.

Additionally, oxygen (O2) is being reduced, accepting the electrons from glucose and combining with hydrogen (H) to form water (H2O). This reduction process allows for the transfer of electrons and the generation of energy.

The process of cellular respiration is essential for the survival and functioning of organisms, as it provides the necessary energy for various metabolic activities, growth, and maintenance of cellular processes.

It is a fundamental metabolic pathway found in both plants and animals, enabling them to extract energy from organic molecules through the oxidation of glucose or other fuel sources.

Therefore, option C, cellular respiration, is the correct answer that represents the process described by the given redox equation.

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Answer: 2.06%

Explanation:

The chemical formula for sulfuric acid is H₂SO₄.

Find the molar mass of the whole compound:

2(1.01) + 32.07 + 4(16) = 98.02 g/mol

The percent composition by mass of hydrogen can be calculated as:

\(\frac{2.02}{98.02}*100=0.0206*100=2.06\)

Answer:

Density, \(d=1.235\ g/cm^3\)

Explanation:

It is given that, the density is 1,235 kg/m³.

We need to convert the density to g/cm³.

We know that,

1 kg = 1000 g

1 m = 100 cm

\(1235\ kg/m^3=1235\ \dfrac{kg}{m^3} \\\\=1235\times \dfrac{1000\ g}{(100\ cm)^3}\\\\=1.235\ g/cm^3\)

So, the density is \(1.235\ g/cm^3\).

The bond length between C and O is 1.129 × 10⁻¹⁰ m, while the rotational constant B is 1.1481 ×  10⁻²² J.

Only transitions between consecutive rotational levels are permitted under the selection conditions, which stipulate that the molecule must have a permanent dipole moment (J=J1). Molecules like HF and HCl have pure rotational spectra because of the requirement for a dipole, but molecules like H2 and N2 are not rotationally active.

EJ = BJ(J+1)

ΔE = B(J+1) - BJ = B

B = ΔE = 3.84235 cm⁻¹ = 1.1481 × 10⁻²² J

μ = m1m2/(m1+m2)

B = h/(8π²cμ)

μ = m1m2/(m1+m2) = 15.999 × 12.011/(15.999 + 12.011) amu

= 6.6560 amu

B = h/(8π²cμ) = 1.1481 × 10⁻²² J

6.6560 amu = 1.66054 × 10⁻²⁷ kg/amu

h = 6.62607 × 10^⁻³⁴ J s

c = 2.99792 × 10⁸ m/s

B = h/(8π²cμ) = 1.1481 × 10⁻²² J

r = (h/(8π²cBμ))² = 1.129 × 10⁻¹⁰ m

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Answer:

the best tool for separating marbles from water is evaporation disc