In which grouping of the periodic table do the elements have similar properties?

only columns

both rows and columns

only rows
in the periods

Answer:

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

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:

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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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.

The solution to these stoichiometric problems in the fermentaion process indicates that 500g of glucose would produce 256g of ethanol, 100g of glucose would produce 24.8L of CO2 at STP and if 17.5 moles of ethanol were produced, it would have taken 8.75 moles of glucose.

The questions are centered on stoichiometry which relates to the quantitative relationship between reactants and products in a chemical reaction.

A. The molar mass of glucose (C6H12O6) is calculated as 180.16 g/mol. However, in the provided chemical equation, 1 mol of glucose produces 2 mols of ethanol. Therefore, the molar mass of ethanol (C2H5OH) is 46.07 g/mol. Therefore, 500g of glucose is equal to 500 / 180.16 = 2.776 moles. So, this would produce 2.776 * 2 * 46.07 = 256g of ethanol.

B. The molar mass of glucose (C6H12O6) is 180.16 g/mol and 100g would be 100 / 180.16 = 0.555 moles of glucose. This would produce 0.555 * 2 = 1.11 moles of CO2. At STP, 1 mole of gas occupies 22.4L. Therefore, 1.11 moles of CO2 will produce 1.11 * 22.4 = 24.8L of CO2.

C. As per the reaction, 1 mole of glucose makes 2 moles of ethanol. Therefore, if 17.5 moles of ethanol were produced, it would have taken 17.5 / 2 = 8.75 moles of glucose.

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Answer:

B) Cohesion

Explanation:

The water molecules are more attracted to themselves than with air molecules. Droplets will cling to the body of water due to cohesion.

Answer:

E = Surface Tension

Explanation:

Insects are able to walk on water mainly due to surface tension. The insects legs have a very large surface area on their legs which enables them to walk on water. Another factor is their extremely light weight which enables them to exert a force on the surface of the water without breaking its film (surface area).

Answer:

Iron (Fe)

Explanation:

The number of electrons (-) is usually the same as the number of protons (+) in the atom of the element (unless it is an ion).

The element described has 26 electrons, so we can assume that it has 26 protons as well. The number of protons in an atom is the atomic number of element that the atom is.

Element 26 on the PTE is Iron (Fe), which does rust (oxidation) in air and water.

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: X = 5

Explanation: 4x + 7 = 22 + x​

Collect like terms

4x — x = 22 — 7

3x = 15

3x/3 = 15/3

X = 5

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:

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:

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: 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: 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: 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: hey buddy its not "blome" its biome

The correct term, which is used to describe the water coming from the sky due to the condensation of the water present in the cloud is precipitation. The precipitation is the water, which comes in form of the rain, hail, snow, drizzle or sleet. This is one of the main sources of the water supply in the biome.

i hope ur looking 4 the one underlined  

The natural supply of water in the form of rain in a biome is known as precipitation, which is a key component of the Earth's water cycle.

In a biome, the term that refers to the natural supply of water in the form of rain is called precipitation. Precipitation can come in various forms such as rain, snow, sleet, and hail. When precipitation falls on the land, some of it may infiltrate the soil, replenishing groundwater supplies, or contribute to surface water bodies. This is a critical component of the Earth's water cycle, which includes infiltration and the water balance concept, where precipitation is balanced with other processes such as evaporation and transpiration.

Answer:

True

Explanation:

Answer:

TRUE

Explanation:

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:

[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:

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.

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:

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:

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:

noble gas

Explanation:

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

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:

2-d

3- d

4. c

5. c

6. a

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:

-38.83°C

Explanation: