Calcium has a density of 2.72 g/ml. What is the mass of 24.9 ml of calcium?

Answer:

Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state. ... The reverse process of sublimation is deposition or desublimation, in which a substance passes directly from a gas to a solid phase.

Answer:

5.52

Explanation:

2.76 10^-3 M = 2.76mM

2.76mM*2L= 5.52mmol

Answer:

give answer of following questions and get 35 points.

Answer:

from the spaces left between chains when the polymer is

formed.

Explanation:

Polyethylene polymer may be of high or low density. Whether the polymer is of high or low density depends on the arrangement of the polymer chains.

If the polymer chains are close together such that the resultant polymer is crystalline with chains packed closely, we have high density polyethylene.

On the other hand if the chains are not close together and there are spaces left between chains when the polymer is formed, then we have low density polyethylene.

Hence, low density polyethylene gets its name from the spaces left between chains when the polymer is formed.

Answer: it gets its name (from the process by which it's polymerized). Therefore the correct option is A.

Explanation:

Polyethylene is a type of plastic which is made by the polymerization of its monomers (ethene). The most common monomers are derived from petrochemicals. The monomers simply join together to form the polymers which has the same empirical formula as the monomer, but is of a higher molecular mass.

There are two main types of polyethylene, these include:

--> Low density polyethylene: when ethene is subject to a high temperature of about 250°C and pressure above 1500atm, together with traces of oxygen ( as an initiator), it polymerizes to polyethylene. The polyethylene obtained by the above method is called a low density polyethylene. It has the most long- and short-chain branching of any form of polyethylene, resulting in its lower density. Therefore its name is gotten from the process by which it's polymerized

--> High density polyethylene: this is prepared at a lower temperature and pressure by using catalysts.

Answer:

It is used by the organism itself for respiration.

Answer:

c or d

Explanation:

it says it was playing classic music

In this case, the control group or control variable is the greenhouse where the plants are grown in silence, as this group does not receive any music treatment. Therefore, the correct answer is A.

Variables can be defined as any characteristics, number or a quantity that can be measured . It is also  called as a data item . It is called as variable because it can vary and can also have  wide variety of values.

There are 3 types of variables 1) manipulated variable where the condition is specified, 2) responding variable which is dependent on the manipulated variable 3)controlled variable which does not change.

In this experiment, the control group is the group that does not receive the experimental treatment and serves as a basis for comparison.

Thus, the correct answer is A , the silent greenhouse.

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Answer:

9.7 ml

Explanation:

Molarity = 2.5 M

Mass = 0.97g

Volume = ?

The relationship between these quantities is;

Molarity = Number of moles / Volume

Number of moles = Mass / Molar mass

Molar mass of NaOH = 40g/mol

Number of moles = 0.97 / 40  = 0.02425 mol

Volume = Number of moles / Molarity = 0.02425 / 2.5 = 0.0097 L

1000 ml = 1L

x = 0.0097 L

x = 0.0097 * 1000 = 9.7 ml

The electron configuration for each of the following elements is provided below along with the symbol of the previous noble gas in brackets to represent the core electrons.1.

The electron configuration of an atom represents the distribution of electrons within the atom's atomic orbitals. Each electron shell is filled with electrons, beginning with the innermost shell, which is closest to the nucleus, and progressing outward. The symbol of the previous noble gas in brackets represents the core electrons.

The electron configuration of Ga, which has atomic number 31, is as follows: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p¹ (Ar)The electron configuration of As, which has atomic number 33, is as follows: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³ (Ar)The electron configuration of Rb, which has atomic number 37, is as follows: 1s²2s²2p⁶3s²3p⁶4s¹ (Kr)The electron configuration of Sn, which has atomic number 50, is as follows: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p² (Kr)

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The mass of KClO₃ that was decomposed in the given reaction by the ideal gas equation is approximately 7.19 grams.

Given:

Pressure (P) = 0.964 atm

Volume (V) = 0.65 L

Temperature (T) = 22 °C = 22 + 273.15 = 295.15 K

The ideal gas law: PV = nRT

Where:

P = Pressure in atm

V = Volume in liters

n = Number of moles

R = Ideal gas constant = 0.0821 L·atm/(mol·K)

T = Temperature in Kelvin

n = (PV) / (RT)

n = (0.964 atm) × (0.65 L) / (0.0821 L·atm/(mol·K) × 295.15 K)

n ≈ 0.0294 mol

2 moles of KClO₃ produce 1 mole of O₂. Therefore, the number of moles of KClO₃decomposed would be:

Moles of KClO₃= 2 × 0.0294 mol

Moles of KClO₃≈ 0.0588 mol

Molar mass of KClO₃= 122.55 g/mol

Mass of KClO₃= Moles of KClO₃× Molar mass of KClO₃

Mass of KClO₃≈ 0.0588 mol × 122.55 g/mol

Mass of KClO₃≈ 7.19 grams

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Answer:

Ionization energy

Explanation:

Thermometer 2 had ethanol as the thermometric liquid because the change in volume with an increase in temperature was smaller compared to Thermometer 1 containing 1-propanol due to stronger intermolecular forces in ethanol.

The change in volume of a liquid with an increase in temperature is characterized by its coefficient of thermal expansion, which is different for different liquids.

Ethanol has a coefficient of thermal expansion of about 1.2 x 10⁻³ K⁻¹, while 1-propanol has a coefficient of thermal expansion of about 1.5 x 1010⁻³ K⁻¹. This means that 1-propanol has a higher change in volume with an increase in temperature compared to ethanol. Therefore, 1-propanol has the highest change in volume with an increase in temperature between the two liquids.

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The total bond energy of the reaction is - 183 kJ/mol and the reaction is exothermic.

The given reaction,

N₂ + O₂ → 2NO

Total bond energy ΔH of the reaction can be calculated by using the formula,    

ΔH = Total bond energy of the reactants - Total bond energy of the products

Here the bonds between N₂ and O₂ are broken,

Energy of broken N₂ and O₂ bond = 1443 KJ/mol

The bonds formed are NO,

Energy of the formed NO bond = 1260 KJ/mol

Total bond Energy ΔH,

ΔH = 1260 - 1443 KJ/mol

ΔH = -183 KJ/mol

As we can see that the value of ΔH is negative. In thermodynamics, if the value total bond energy comes out to be negative then it means that the system is liberating heat and that is why the reaction is said to be exothermic.

So, the Total bond energy of the reaction is -183KJ/mol and the reaction is exothermic.

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The synthesis of aromatic 1,2-amino alcohols using a bienzymatic dynamic kinetic asymmetric transformation (bienzymatic DKAT) is a 3 step process involving synthesis of ketones, enantioselective reduction of lactols and synthesis of aromatic 1,2-amino alcohols

Step-by-step method :

Step 1: Synthesis of ketones

Starting with a ketone as the substrate, add the enzyme galactose oxidase (GOx) and an oxidant such as sodium periodate (NaIO4) to convert the ketone to a lactol. This transformation takes place at room temperature in a mixture of water and tetrahydrofuran (THF). The reaction mixture was then filtered to remove any precipitate, and the aqueous phase was extracted with ethyl acetate (EtOAc) to give the product in good yield.

Step 2: Enantioselective reduction of lactols

Use the enzyme alcohol dehydrogenase (ADH) and an NADH cofactor to perform an enantioselective reduction of lactols. This transformation takes place at room temperature in a mixture of water and isopropanol (IPA). The product is a chiral alcohol with high enantioselectivity.

Step 3: Synthesis of aromatic 1,2-amino alcohols

The chiral alcohol can be transformed into an amino alcohol using a reductive amination reaction with ammonia or an amine. This transformation takes place at room temperature in a mixture of water and ethanol (EtOH) or isopropanol (IPA). The resulting product is a 1,2-amino alcohol with high diastereoselectivity and enantioselectivity. This bienzymatic DKAT method is an effective and efficient way to synthesize aromatic 1,2-amino alcohols.

Thus, the step-by-step method of synthesis of aromatic 1,2-amino alcohols using a bienzymatic dynamic kinetic asymmetric transformation is explained above.

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The pile of firewood  does not immediately release the energy in its chemical bonds because activation energy is higher in case of solids where forces of attraction is maximum.

Forces of attraction  is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different  states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases  as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

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Approximately 0.023% of the original thorium sample still exists today. A 25.2 g sample of thorium was discovered in Norway in 1882.

Given,

A 25.2 g sample of thorium was discovered in Norway in 1882, and the most sustainable isotopes of thorium has a half-life of 14.05 billion years.

Let's assume that at the start of the universe, there were x grams of thorium, and half-life is 14.05 billion years.

So, after the first half-life, there will be x/2 grams left, and

after the second half-life, there will be x/4 grams left and so on.

This process can be expressed using the formula

N = N0 (1/2)^(t/h) ,where Nis the current amount of thorium,

N0 is the original amount of thorium,

t is the time that has passed, and h is the half-life of thorium

The amount of thorium is the current amount of thorium, .

N0 is the original remaining today after 14.05 billion years can be calculated as follows:

N = N0 (1/2)^(t/h)N = 25.2 g (1/2)^(14.05 billion years/14.05 billion years)

N ≈ 0.00576 g

Therefore, approximately 0.023% of the original thorium sample still exists today.

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Answer:

false, The nucleus of atoms still move around like crazy, it's just the electrons move more.

C, O, and F have less exothermic electron affinity than Si, S, and Cl respectively is due to their atomic structure and the stability of their outermost electron shells.

Carbon (C), Oxygen (O), and Fluorine (F) are all located in the second period of the periodic table, which means they have two electron shells. Silicon (Si), Sulfur (S), and Chlorine (Cl) are all located in the third period, which means they have three electron shells. The electron affinity of an atom is the amount of energy released when an electron is added to a neutral atom to form a negative ion. Atoms with a higher electron affinity release more energy when an electron is added, making the process more exothermic.

In the case of C, O, and F, their outermost electron shells are already relatively stable with 4, 6, and 7 electrons respectively. Adding an additional electron would disrupt this stability and require more energy. In contrast, Si, S, and Cl have a less stable outermost electron shell with only 4, 6, and 7 electrons respectively in their third shell. Adding an additional electron to these atoms would increase their stability and release more energy, resulting in a more exothermic electron affinity. Therefore, C, O, and F have less exothermic electron affinity than Si, S, and Cl respectively due to the stability of their outermost electron shells.

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Answer: 27 g of Fe2(SO4)3

Explanation:

I'm assuming that there is an error in the original question: Fe2(SO3)4 is not a likely product. Indeed, a reactant of FePO4 would suggest that we are working with Fe atoms with +3 charge, however, the product Fe2(SO3)4 would have Fe atoms with a 0 charge (since SO3 is normally neutral), which is not consistent.

The correct product should be Fe2(SO4)3.

Proceeding under this corrected information:

First we must determine the balanced chemical equation. To do this, start by noting the relevant charges of the reactants:

FePO4:  PO4 = -3 charge,  Fe = +3 charge

Na2SO4:  SO4 = -2 charge,  Na = + 1 charge.

Then, in order to keep the charges balanced, the reaction must be:

\(2 \ \text{FePO}_4 + 3 \ \text{Na}_2\text{SO}_4 \rightarrow 2\ \text{Na}_3\text{PO}_4 + \text{Fe}_2(\text{SO}_4)_3\)

Next, we assume that we have excess Na2SO4. Then,

20 g FePO4  
x 1 mol FePO4 / (150.82 g FePO4)
x 1 mol Fe2(SO4)3 / (2 mol FePO4)
x 399.88 g Fe2(SO4)3 / (1 mol Fe2(SO4)3)
--------------------------
26.51 g Fe2(SO4)3

which we report as 27 g Fe2(SO4)3 after applying significant figures.

Answer:

The water freezes and becomes solid ice

Answer:

See below

Explanation:

Water freezes at 0 C

  so the water will give up heat to become 0 C  water

     then it will give up more heat to become  0 C   ice

          then it will give up even more heat to become  -10 C ice

Answer:

The earth is made of chemical

Explanation:

Explanation:

because of the chemical made up with earth

Answer:

10.true

11.false

12.true

Answer:

This means that solution A is 1000 times more acidic than solution B.

Explanation:

A solution with a pH of 2.0 is more acidic than a solution with a pH of 5.0. The reason is that pH is a logarithmic scale, which means that every whole number increase or decrease in pH represents a tenfold increase or decrease in the concentration of hydrogen ions (H+).

The pH scale ranges from 0 to 14, with 7 being neutral. Solutions with a pH below 7 are considered acidic, and those above 7 are considered basic or alkaline.

To calculate the hydrogen ion concentration in each solution, we can use the formula:

[H+] = 10^-pH

For solution A (pH = 2.0):

[H+] = 10^-2.0 = 0.01 mol/L

For solution B (pH = 5.0):

[H+] = 10^-5.0 = 0.00001 mol/L

We can see that solution A has a higher hydrogen ion concentration than solution B, which means that it is more acidic.

To determine how many times more acidic solution A is compared to solution B, we can calculate the ratio of their hydrogen ion concentrations:

[H+] solution A / [H+] solution B = 0.01 mol/L / 0.00001 mol/L = 1000

Since the volume decreased, it means that the pressure is going to rise. Thus, the equilibrium of the reaction will shift in the direction that has the least amount of moles.

The statement, that describes the equilibrium "will change in the direction with the minimum moles."

A condition of equilibrium has become one of balance. Chemical equilibrium is the state in which both the reactants and products are present in concentrations that have no further tendency to change with time, resulting in no observable change in the system's properties.

When volume decreases, the equilibrium shifts to favor the direction that produces fewer moles of gas. When the volume is raised, the equilibrium shifts in favor of the direction that produces the most moles of gas. Because the container's volume will be lowered from 5.0 L to 3.0 L, the pressure will rise. As a result, the equilibrium of the reaction will shift in the direction with the fewest moles. When the volume is reduced, the pressure rises. This demonstrates that a gas's pressure is inversely proportional to its volume.

Hence the correct answer is equilibrium will change in the direction with the minimum moles.

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After exactly 8 half-lives, only 1/256th (1/2 to the 8th power) of the original sample will remain.

This is because the rate of radioactive decay is exponential, meaning that the amount of radioactive material decreases exponentially as the number of half-lives passes. As a result, after eight half-lives, only a tiny fraction of the original sample will remain.

Over time, the amount of material that decays is increasingly greater with each passing half-life. After the first half-life, half of the sample is gone; after the second, three quarters of it is gone; and after the third, seven eighths of it is gone.

This pattern continues until, after the eighth half-life, only 1/256th of the original sample remains.

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An investigation into an unknown object in space resulted in the following observations: It was discovered to be an asteroid, It revolves around the sun, which is in the third position.

It is a small, rocky substance that rotates around the sun and is found in the asteroid belt, which is located between the orbits of Mars and Jupiter, and its size varies, with some still in fragments and others having a large structure.

Hence, an investigation into an unknown object in space resulted in the following observations: It was discovered to be an asteroid, It revolves around the sun, which is in the third position.

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150mg, which is equivalent to 0.15g, will be needed to make 150mL of the hemoglobin solution.

Mass is a quantity of matter which a body contains, irrespective of its bulk or volume. It is one of four fundamental properties of matter. It is measured in kilograms in the SI system of measurement or grams, milligrams etc.

According to this question, one needs to make 150 mL of a 1 mg/mL hemoglobin solution. This means that;

1mg = 1mL

Hence, 150mL will need 150mg

Since 1mg = 0.001g

150mg = 150 × 10-³ = 0.15grams.

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Answer:

Corona Virus Disease

Explanation:

Its a virus and a disease

Answer:

Viral Infections

Viruses are very tiny germs. They are made of genetic material inside of a protein coating. Viruses cause familiar infectious diseases such as the common cold, flu and warts.

Explanation:

If the concentration of fluoride anion and aluminum cation was increased to 5M, then there would be decrease in Ecell by 0.055 volts

The standard reduction potential of Fluoride anion and aluminum cation are -

2Al -----> 2Al3+ + 6e-           \(E^o\)cell = +1.66

6e- + 3F2 -----> 6F-               \(E^o\)cell = +2.87

The complete reaction is -

2Al + 3F2 ------> 2Al3+  +  6F-    \(E^o\) = +4.53

Using Nernst Equation :-

E = \(E^o\) – 0.0592/n*log[Al3+]^2[F-]^6

n = 6 (n = number of transferred electrons)

E = +4.53 - 0.0592/6*log(5)^2(5)^6

E = +4.53 - 0.00987*log(25)(1.56 x 10^4)

E = +4.53 – 0.00987*log(3.9 x 10^5)

E = + 4.53 -0.00987(5.59)

E = + 4.53 - 0.055

E = +4.47

The change in Ecell = 5 - 4.47 = 0.055V

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Answer:

Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell