Select all the correct answers.
Sully works as a geologist in the southwestern United States. He plans to choose an unstable isotope to find the absolute age of a rock sample. Which two aspects must he consider before making his choice?
There should be a sufficient amount of the selected isotope in the rock.
The isotope should be one that decays at a very fast rate.
The isotope must not be found in any neighboring rocks.
The half-life of the isotope must be long enough to capture the age of the rock.
There should be more than one unstable isotope in the rock.

Answer: Correct statements are given below:

1) In activity series elements are listed according to their reactivity.

2) Nuclear reaction in which low atomic nuclei fuse to form a heavier nucleus with the release of energy. Nuclear fusion reaction occurs in the sun.

3) C3H8 + 5O2 → 3CO2 + 4H2O is the example of a combustion reaction.

4) 2Fe + O2 → 2FeO is the example of synthesis reaction. In synthesis reaction is a type of reaction in which two reactants combine to form a single product.

The activity series is an arrangement of elements in order of reactivity.

The activity series is an arrangement of elements in order of reactivity. The activity series shows the order in which chemical elements will displace each other in a replacement reaction.

A nuclear fusion is said to have occurred when two light nuclei come together to yield a heavier nucleus with the emission of a tremendous amount of energy. Nuclear fusion occurs in the sun.

A combustion reaction refers to the reaction of a substance with oxygen. A synthesis reaction is a reaction in which two or more substances come together to form a new substance. A combustion reaction which is also a synthesis reaction is 2Fe + O2 → 2FeO.

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Answer: 323.67ml

Explanation:please see attachment for explanation. Thanks

To find the new volume of the nitrogen gas at a different pressure, we can use the gas law equation PV = nRT. By rearranging the equation and plugging in the given values, we can calculate the new volume.

To solve this problem, we can use the gas law equation: PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin. Since the temperature remains constant, we can simplify the equation to PV = constant. First, we need to convert the pressure from mm Hg to atm by dividing it by 760. Then, we can use the equation to find the new volume:

P1V1 = P2V2

Plugging in the values and solving for V2:

V2 = (P1 * V1) / P2

Let's substitute the given values:
V2 = (0.971 atm * 500 ml) / (1140 mm Hg / 760 mm Hg/ atm)

After converting mL to L and performing the calculation, we get:

V2 = 0.207 L

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Answer:

(a) 0.575 m;

(b) 0.527 m

Explanation:

Let's use the freezing point depression law in each of these cases.

(a) According to the law:

[tex]\Delta T_f = iK_fb[/tex]

Rearrange the equation for molality, b:

[tex]b = \frac{\Delta T_f}{iK_f}[/tex]

NaCl is an ionic substance, 1 mole of it dissociates into 2 moles of ions, sodium ion and chloride ion, this means the van 't Hoff factor i = 2.

[tex]\Delta T_f = T_o - T_n[/tex]

Here:

[tex]T_o = 0.00^oC[/tex] is the initial freezing point of water,

[tex]T_n = -2.14^oC[/tex] is the final freezing point of water.

For water:

[tex]K_f = 1.86^oC/m[/tex]

Applying the equation

[tex]b = \frac{2.14^oC}{2\cdot 1.86^oC/m} = 0.575 m[/tex]

(b) Applying the same equation for the same salt and the same conditions, except a new freezing point, we would expect to obtain:

[tex]b = \frac{1.96^oC}{2\cdot 1.86^oC/m} = 0.527 m[/tex]

Final answer:

The molality of salt in the Atlantic ocean seawater sample is calculated to be 0.575 mol/kg, while the molality in the Arctic ocean seawater sample is calculated to be 0.527 mol/kg. This is determined using the freezing point depression formula.

Explanation:

The subject of this question is the Calculation of Molality based on the observed freezing point depression of seawater samples from the Atlantic and Arctic Oceans. The freezing point depression phenomenon is when the freezing point of a liquid is lowered by adding a solute, such as salt in seawater. The formula to calculate molality (m) is derived from the freezing point depression formula: ΔT = i * Kf * m, where ΔT is the depression of the freezing point, Kf is the cryoscopic constant of water (1.86 °C kg/mol), m is the molality, and i is the van't Hoff factor (which is 2 for NaCl, as it dissociates into two ions).

Steps to Calculate Molality:

Calculate the freezing point depression (ΔT) by subtracting the freezing point of seawater from the freezing point of pure water (0°C).

Apply the formula ΔT = i * Kf * m, where i = 2 for NaCl, Kf = 1.86 °C kg/mol.

Rearrange the formula to solve for m (molality), which gives m = ΔT / (i * Kf).

Calculating for the Atlantic seawater sample: The freezing point depression is 0°C - (-2.14°C) = 2.14°C. Using the rearranged formula:

molality = 2.14°C / (2 * 1.86°C kg/mol) = 0.575 mol/kg

Calculating for the Arctic seawater sample: The freezing point depression is 0°C - (-1.96°C) = 1.96°C. Using the rearranged formula:

molality = 1.96°C / (2 * 1.86°C kg/mol) = 0.527 mol/kg

In conclusion, the molality of salt in the Atlantic ocean seawater sample is 0.575 mol/kg, and in the Arctic ocean seawater sample is 0.527 mol/kg.

Answer:

[tex]K_2S[/tex]

Explanation:

According to the boiling point elevation law described by the equation [tex]\Delta T_b = iK_bb[/tex], the increase in boiling point is directly proportional to the van 't Hoff factor.

The van 't Hoff factor for nonelectrolytes is 1, while for ionic substances, it is equal to the number of moles of ions produced when 1 mole of salt dissolves.

[tex]NaBr[/tex] would produce 2 moles of ions per 1 mole of dissolved substance, sodium and bromide ions.

[tex]Ca_3(PO_4)_2[/tex] is insoluble in water, so it would barely dissociate and wouldn't practically change the boiling point.

[tex]K_2S[/tex] would dissociate into 3 moles of ions per 1 mole of substance, two potassium cations and one sulfide anion.

[tex]CO_2[/tex] is a gas, it would form some amount of carbonic acid when dissolved, however, carbonic acid is molecular and would yield i value of i = 1.

Therefore, potassium sulfide would raise a liquid's boiling point the most if all concentrations are equal.

Answer:

The statement which is false is b. Electrons are negatively charged and have a mass of 1 amu.

Explanation:

Protons can be described as the positively charged part of an atom. Neutrons are the part of an atom which do not carry ant charge. The protons and neutrons are present in the nucleus of an atom. The atomic mass unit of a proton and a neutron is almost 1.

Electrons are the negative charge particles of an atom. They do not have a mass of 1 atomic mass unit. Their atomic mass unit is almost zero. Hence, option B is false.

Answer:

2-d

3- d

4. c

5. c

6. a

Explanation:

Answer: X = 5

Explanation: 4x + 7 = 22 + x​

Collect like terms

4x — x = 22 — 7

3x = 15

3x/3 = 15/3

X = 5

Answer:

The correct option is B) Because their embryos have structures similar to

gills, chickens and humans likely share a common  ancestor with fish.

Explanation:

Evolutionary studies show common traits which are present among organisms of different species. Based on these traits, we can tell that which species might have shared common ancestors in the past.

In the structure shown above, we can see that the embryo of a human and a chicken have a structure  similar to the gills of fishes. This shows that these organisms might have shared a common ancestor in the past.

Answer:

The correct answer is B

Answer:

Aquatic ecosystem has two components -

     2.Abiotic components

temperature and amount of sunlight are the part of abiotic component .

while living things like sponges and planktons are the biotic components of ecosystem.

Explanation:

aquatic components are of two types-

freshwater ecosystem( lakes and ponds, river and streams)

marine ecosystem(ocean ecosysyem, estuaries)

planktons-

planktons are found in limnetic zone, availability of sunlight is much here. planktons  are zooplanktons and phytoplanktons  are very important link in aquatic ecosystem.

sponges

In marine water, the benthic zone is the area below the pelagic zone. Here temperature decreased because of less light perception. This zone is very nutrient rich so organisms which are present here are- bacteria, fungi, sea anemone, sponges and some fishes.

Answer:  All of the given choices.

Explanation:

The ecosystem can be defined as the combination of the biotic and abiotic factors. The biotic factors consists of the living systems and the abiotic factors consists of the non living parts of the ecosystem.

The biotic part of the aquatic ecosystem is sponges and plankton. This is because they are living.

The abiotic part of the aquatic system consists of amount of sunlight ad temperature of water because they are non living.

Answer:

Explanation:

Balanced Chemical equation:

HClO₂(aq) + NaOH(aq) → H₂O(l) + NaClO₂ (aq)

Ionic equation:

H⁺(aq) + ClO₂⁻(aq) + Na⁺(aq) + OH⁻(aq) → H₂O(l) + Na⁺(aq) + ClO₂⁻ (aq)

Net ionic equation:

H⁺(aq) + OH⁻(aq) → H₂O(l)  

The ClO₂⁻(aq) and Na⁺ (aq) are spectator ions that's why these are not written in net ionic equation. The water can not be splitted into ions because it is present in liquid form.

Spectator ions:

These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.  

Chemical equation:

NaCl(aq) + KBr(aq)  → NaBr(aq) + KCl(aq)

Ionic equation:

Na⁺(aq)  + Cl⁻(aq) + K⁺(aq)  + Br⁻(aq)  → Na⁺(aq) + Br⁻(aq) + K⁺(aq)  + Cl⁻(aq)

Net ionic equation can not be written for this reaction because nothing is changed on both side. There is no solid, liquid and gaseous product. All are aqueous and cancel each other.

Answer:

3

Explanation:

According to law of conservation of mass energy and charge the mass energy and charge will remain conserved.

Answer:

True

Explanation:

Answer:

TRUE

Explanation:

200 moles of nitric acid.

Explanation:

We have the following chemical equation:

3 NO₂ + H₂O → 2 HNO₃+ NO

Taking in account the chemical equation, we devise the following reasoning:

if        3 moles of nitric dioxide (NO₂) produce 2 moles of nitric acid (HNO₃)

then  300 moles of nitric dioxide (NO₂) produce X moles of nitric acid (HNO₃)

X = (300 × 2) / 3 = 200 moles of nitric acid.

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Answer:

q = - 2067.2 J of Heat is giving out when 85.0g of lead cools from 200.0 c to 10.0 c.

Explanation:

The Specific Heat capacity of Lead is 0.128 [tex]\frac{J}{g\ ^{0}C}[/tex]

This means, increase in temperature of 1 gm of lead by [tex]1 ^{0}\ C[/tex] will require 0.128 J of heat.

Formula Used :

[tex]q = m.c.\Delta T[/tex]

q = amount of heat added / removed

m = mass of substance in grams = 85.0 g

c = specific heat of the substance = 0.128

[tex]q = m.c.\Delta T[/tex] = Change in temperature

                                          = final temperature - Initial temperature

                                          = 10 - 200

                                          = -[tex]190 ^{0}\ C[/tex]

put value in formula

q = -  [tex]85\times 0.128\times 190[/tex]

On calculation,

q = - 2067.2 J

- sign indicates that the heat is released in the process

Answer:

the continents of earth were clustered together in formation that a scientist named Pangaea.

Explanation:

Before 300 million years ago, our earth was not made up of 7 different continent what we have now. Instead it was single huge mass land that was surrounded by a single ocean called  Panthalassa. A lot of  migration and collision lead to the formation of Pangaea. An Scientist named Albert Wegener gave the name Pangaea. Later, Pangaea was broken into  Gondwanaland and Laurasia.These Lands were then divided into 7 continents.

Answer:

Your answer is:

Explanation:

A) The acceleration due to gravity for any object, including 1 washer on the string, is always assumed to be  10  m/s2.

B) The mass of 3 washers, when converted to kg, is  0.0147  kg.

C) The applied force of 3 washers will increase the applied force on the car to 0.147  N.

I hope this helps!

- sincerelynini

Answer:

A) 10 m/(s^2)

B) 0.0147 kg

C) 0.147 N

Explanation:

A) It's stated in the table that the acceleration due to gravity is assumed as 10 m/(s^2).  If you assume this value in one calculation, then you have to assume the same value in all your calculations.

B) 3 washers have a mass of 14.7 grams. Dividing this mass by 1000, you convert grams into kilograms, that makes 0.0147 kg.

C) Force measured in kilograms times meters per second squared are equivalent to Newtons, therefore, 0.147 kg*m/(s^2) = 0.147 N

Answer:

noble gas

Explanation:

The group that tells the three unifying characteristics of chordates is "notochord, gill slits, dorsal nerve cord."

Chordates are a group of animals that have these three key features:

1. Notochord: This is a flexible rod-like structure that runs along the length of the animal's body. It provides support and helps with locomotion.

2. Gill Slits: Chordates have openings called gill slits in their throat region. These slits are used for respiration in aquatic chordates, allowing them to extract oxygen from the water.

3. Dorsal Nerve Cord: Chordates have a nerve cord that runs along their back, called the dorsal nerve cord. This cord is part of their nervous system and serves as the main communication pathway between the brain and the rest of the body.

By having these three characteristics, notochord, gill slits, and dorsal nerve cord, animals can be classified as chordates. Remember that these characteristics may vary or be modified in different groups of chordates, but they are the unifying traits that define the chordate group.

Answer:

Hydrochloric acid (HCl)

Answer: C

Explanation:

Answer: Hybridization

Explanation:

I did it on ck12 and got it right and here’s this short story of it

Final answer:

Annealing refers to the process in which two complementary DNA strands bind through hydrogen bonds between their base pairs, A-T and G-C, which are essential in maintaining the structure and function of the DNA double helix.

Explanation:

The process where two genetic sequences bind together because of the hydrogen bonds that form between the base pairs is known as annealing. This is a critical aspect of DNA structure and function, where the complementary base pairs A-T (adenine-thymine) and G-C (guanine-cytosine) come together. The hydrogen bonds hold the bases together, with A and T forming two hydrogen bonds, and G and C forming three hydrogen bonds. This mechanism is not only crucial in the formation of the double helix structure of DNA but is also vital during the processes of DNA replication and transcription, where the genetic code is copied and read to synthesize proteins.

Answer:

Energy should be saved and controlled as it is better for the environment. Excess use of energy of any kind can be disastrous. For example, a kind of energy is stored in the food. If excess food is consumed and wasted, then the country and other people will have to face consequences of it. Malnutrition will rise.

Another kind of energy is the energy in the fuel. If fuel consumption is not controlled then in the near future the resources for the making of fuel will be depleted.

Answer:

Explanation:

According to the theory of plate tectonics, Earth is an active planet. Its surface is composed of many individual plates that move and interact, constantly changing and reshaping Earth's outer layer. Volcanoes and earthquakes both result from the movement of tectonic plates. Plates sliding past each other cause friction and heat. Subducting plates melt into the mantle, and diverging plates create new crust material. Subducting plates, where one tectonic plate is being driven under another, are associated with volcanoes and earthquakes.

Answer:

Plates sliding past each other cause friction and heat. Subducting plates melt into the mantle, and diverging plates create new crust material. Subducting plates, where one tectonic plate is being driven under another, are associated with volcanoes and earthquakes.

Answer:

tar and nicotine which are produced when the tobacco leaves are burning.

Answer: Option (1) is the correct option that is currents deflect to the right due to the rotation of Earth.

Explanation:

The water on the surface of ocean is moved by winds that blow in certain direction because of the Coriolis effect and spinning of the Earth that's why ocean currents in the Northern hemisphere tend to move in the clock-wise direction.

Answer:

Coefficients are the numbers in front of the formulas.

Answer:

a coefficient is a multiplicative factor in some term of a polynomial, a series, or any expression; it is usually a number, but may be any expression. In the latter case, the variables appearing in the coefficients are often called parameters, and must be clearly distinguished from the other variables.

For example, in

7x^{2}-3xy+1.5+y,}{\displaystyle 7x^{2}-3xy+1.5+y,}

Explanation:

Answer:

This is an oxidation/reduction reaction.

Explanation:

C is oxidized (loses electrons) and iron is reduced (gains electrons).  C goes from oxidation number zero on the left to oxidation number 4+ on the right.  Iron goes from oxidation number 3+ on the left to zero on the right.

Physical properties of copper metal are high thermal conductivity, high electrical conductivity, ductility, malleability etc.

A physical property is a characteristic of matter that can be observed or measured without changing the substance itself. Examples include color, shape, density, and melting point.

Copper is a metal that has several physical properties that make it useful in various applications. Some of the physical properties of copper are:

1. High thermal conductivity: Copper is an excellent conductor of heat, which makes it useful in various applications such as electrical wiring, plumbing, and heating systems.

2. High electrical conductivity: Copper is also an excellent conductor of electricity, which makes it useful in electrical wiring and other electrical applications.

3. Ductility: Copper is a highly ductile metal, which means it can be easily drawn into wires or other shapes without breaking.

4. Malleability: Copper is a highly malleable metal, which means it can be easily shaped or flattened into thin sheets.

5. Corrosion resistance: Copper is resistant to corrosion, which makes it useful in various applications where it is exposed to moisture or other corrosive materials.

In conclusion, high thermal conductivity, high electrical conductivity, ductility, malleability are the physical properties possessed by copper.

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Final answer:

A physical property of copper includes its malleability, ductility, high thermal and electrical conductivity, and its characteristic pinkish-orange color when freshly exposed.

Explanation:

The question involves identifying a physical property of copper. A physical property can be observed or measured without changing the substance's identity. For copper, some of its physical properties include its reddish-brown color, malleability, ductility, and high thermal and electrical conductivity. Since copper is such a good conductor of electricity, it is often used in electrical wiring. Being ductile, it can be stretched into wires without breaking. Copper's pinkish-orange color when freshly exposed is another key physical property.

Answer:

Charles' law states that the volume and temperature of a gas have a direct relationship: As temperature increases, volume increases, when pressure is held constant. Heating a gas increases the kinetic energy of the particles, causing the gas to expand.

Explanation:

Final answer:

If the temperature of a gas is increased while keeping the volume constant, the pressure will increase. If the temperature is decreased, the pressure will similarly decrease. This relationship is described by Gay-Lussac's Law.

Explanation:

When you change the temperature of a gas but keep the volume the same, according to Gay-Lussac's Law, the pressure of the gas changes directly with its absolute temperature. In other words, if you increase the temperature of the gas, the pressure will increase as well. Conversely, if you decrease the temperature, the pressure will decrease, as long as the volume is kept constant.

Temperature and Pressure Relationship

The relationship between temperature and pressure in a gas at constant volume is given by the equation P1/T1 = P2/T2, where P1 and P2 are the initial and final pressures, and T1 and T2 are the initial and final absolute temperatures respectively. So, to find out how the pressure changes with temperature, you can rearrange the formula to solve for the new pressure. Essentially, if you double the absolute temperature (measured in Kelvin), you double the pressure.

Answer:

It can't be done.

Explanation:

If you have only 5.4 g of oxygen, the most lithium oxide you can get is 7.7 g.

Only 2.3 g of lithium will react. and the other 22.3 g of lithium will not be used.

Answer:

51.094 g/mol

Explanation:

We are given;

We are required to determine the molar mass of M

Step 1: Determine the percentage by Mass of Oxygen in the compound

% by mass of Oxygen = 100% -68.04%

                                   = 31.96%

Step 2: Mass of M in the compound

Mass of oxygen in the compound = 16.0 g × 3 atoms

                                                        = 48.0 g

Therefore; 48.0 g is equivalent to 31.96% of the compound.

Thus; 68.04 % will be equivalent to a mass of ;

= (48.0 g × 68.04%) ÷ 31.96%

= 102.188 g

Step 3: molar mass of M

Mass of M in the compound is 102.188 g

But there are two atoms of M in the compound

Therefore; Molar mass of M = 102.188 g ÷ 2

                                              =51.094 g

Thus, the molar mass of M is 51.094 g/mol

To find the molar mass of a metal in a compound with empirical formula M2O3, assume a 100 g sample and calculate moles of metal and oxygen. The molar mass is found by dividing the mass of metal by its moles. The closest actual metal molar mass corresponds to aluminum.

To calculate the molar mass of a metal that forms an oxide with the empirical formula M2O3, we'll start by taking the given percentage of the metal in the compound and assume a 100 g sample for ease of calculation. The mass of the metal in this sample is 68.04 g, and the mass of oxygen is the remaining 31.96 g.

Next, we'll find the number of moles of each element in the compound:

Since the empirical formula is M2O3, this means there are two moles of metal for every three moles of oxygen. We can set up the ratio like this:

We will use the moles of oxygen to figure out the moles of the metal required to form this ratio:

(2 moles M / 3 moles O) = x moles M / 1.9975 moles O

Solving for x gives us:

x = (2/3) * 1.9975 = 1.3317 moles of M

Now, we can calculate the molar mass of the metal by dividing the mass of metal by the moles of metal:

Molar mass of M = 68.04 g / 1.3317 mol = 51.07 g/mol

The metal with a molar mass close to this value is aluminum (Al), with a molar mass of 26.98 g/mol. Taking into account the empirical formula M2O3, we need two moles of Al to make up the mass, so:

2 * 26.98 g/mol = 53.96 g/mol

The value is close to our calculated molar mass, confirming the metal in the oxide is most likely aluminum.

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