How much heat is required to melt 4 grams of ice at 0°C?​

Answer:

3 and 4

Explanation:

After Rutherford did the alpha particle scattering experiment, he realised that most of the atom must be empty space, and the positive charge needed to be concentrated in the middle of the atom (in the nucleus).

This was because most of the alpha particles went straight through the gold sheet but some were deflected to the side or straight back.

This led to the nuclear model, where Rutherford concluded that most of the mass and all of the positive charge was concentrated in the middle of the atom in the nucleus, and the electrons existed in a sort of negatively charged cloud around the nucleus.

hope this makes sense!

Answer:

national

Explanation:

I don't understand, I'm sorry

160 ml of a 4.0% (m/v) amino acid solution contains 6.4 g of amino acids.

We can use the idea of ​​percent concentration to determine how many grams of amino acids are present in 160 mL of a 4.0% (m/v) amino acid solution. Expressed by the mass percent concentration of the solute (amino acid) per 100 ml of solution. Since the solution in this example is 4.0% (m/v), 100 mL of solution contains 4.0 g of the amino acid.

We can make a ratio to determine how many grams are in 160 ml:

4.0 grams / 100 ml = x grams / 160 ml

When we cross multiply for x, we get:

x = (4.0 grams / 100 ml) * 160 ml

x = (0.04) * 160

x = 6.4 grams

Consequently, 160 mL of a 4.0% (m/v) amino acid solution contains 6.4 g of amino acids.

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Cations are always smaller than the atoms from which they form. Anions are always larger than the atoms from which they form. Ions are usually bigger than the atoms from which they are formed.

When an atom receives or loses electrons, the atom's electron configuration changes, resulting in a net positive or negative charge.

This net charge expands the electron cloud surrounding the nucleus, making the ion bigger in size than the neutral atoms from which it arose. When a metal atom loses one or more electrons to create a cation, it shrinks in size because the positive charge of the nucleus pulls the remaining electrons more strongly.

When a nonmetal atom obtains one or more electrons to create an anion, it normally expands in size.Because of the increasing amount of electrons, the electron cloud surrounding the nucleus grows. It should be noted that this comparison is not absolute and is dependent on the individual factors involved. Some ions are smaller than their neutral atom counterparts, while others are similar in size.

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The complete question is:

Compare the size of ions to the size of atoms from which they form.

False. Chemical weathering of limestone is not an example of incongruent weathering. Incongruent weathering refers to a type of chemical weathering where a mineral decomposes into multiple products that have different chemical compositions than the original mineral.

This typically occurs when a mineral dissolves in water and undergoes a chemical reaction that results in the formation of new compounds. In the case of limestone, the main component is calcium carbonate (CaCO3). When limestone undergoes chemical weathering, it primarily reacts with water and carbon dioxide in the atmosphere through a process called carbonation.

This leads to the formation of calcium bicarbonate (Ca(HCO3)2), which is soluble in water and can be carried away in solution. The chemical composition of the limestone is altered, but the reaction does not produce multiple products with different chemical compositions. Therefore, chemical weathering of limestone is not an example of incongruent weathering.

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Order of decreasing average speed is Nitrogen>oxygen>carbon dioxide

According to Graham's law of diffusion, the rate of diffusion is inversely proportional to the vapour density of the molecule and therefore the smaller the weight of the molecule the faster the rate of diffusion.

Because of the above reason nitrogen has the lowest vapour density followed by oxygen and carbon dioxide with the highest and therefore nitrogen will possess the greatest speed than the others and the decreasing order are nitrogen>oxygen>carbon dioxide.

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is a measure of the tendency of a chemical species to acquire electrons from or lose electrons to an electrode and thereby be reduced or oxidised respectively. Redox potential is measured in volts (V), or millivolts (m

Answer: There are 2.161 x 10^24 molecules present in 3.6 moles CH₁.

Explanation:

Molecules are the the lowest fundamental unit of a chemical molecule that can participate in a chemical reaction is a group of bound atoms. Avogadro's number is used to calculate the number of molecules present in a mole of a substance

Avogadro's number of particles, or around 6.022 x 1023 molecules, are present in one mole of any substance. Therefore the following would be present in 3.6 moles of CH1:

2.161 x 1024 particles are equal to 3.6 moles times 6.022 x 1023 particles per mole.

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The answer is Solution!

Explanation:

Solution is a homogeneous mixture

of two or more substance. In a

sugar solution, sugar gets uniformly

mixed with water

The main differences in the synthesis of purine and pyrimidine nucleotides -

What are 2 differences between purine and pyrimidine?

What are the structural differences among purines and pyrimidines in DNA and RNA?

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Answer:

Mixture of sand, pepper powder and salt can be separated by dissolving the mixture into water. Sand and pepper powder is insoluble in water while salt is soluble. So they are separated by the filtration method.

Answer:

When the bell is rung the switch closes allowing electricity to flow making the hammer hit the bell, making the sound to alert people in the house.

Explanation:

Answer: Replacement means a person or thing that takes the place of another; a substitute.

Answer:

3,4–diethylheptane

Explanation:

To name the compound given in the question above, the following must be obtained:

1. Determine the functional group of the compound.

2. Determine the longest continuous carbon chain. This gives the parent name of the compound.

3. Identify the substituent groups attached to the compound.

4. Give the substituent groups the lowest possible count by naming them alphabetically.

5. Combine the above to obtain the name of the compound.

Now, we shall name the compound given in the question above as follow:

1. The compound belongs to the alkane family since it has only single bonds.

2. The longest continuous carbon chain is 7 i.e the parent name of the compound is heptane.

3. The substituent group attached to the compound is ethyl (–CH2CH3). There are two ethyl groups attached to the compound.

4. The two ethyl group is at carbon 3 and 4 (i.e number from the right to the upper branch chain).

5. The name of the compound is:

3,4–diethylheptane.

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 chemist should add 2588 mL of water to prepare the 0.200 M aqueous solution with 30.2 g of NaCl.

To determine the volume of water needed to prepare the solution, we can use the formula:

mass of solute (g) / molar mass of solute (g/mol) = number of moles of solute

Then, we can use the formula for molarity to find the volume of water needed:

Molarity (M) = number of moles of solute / volume of solution (L)

Given that;

The mass of NaCl = 30.2 g.

Since its molar mass is 58.44 g/mol.

Hence;

30.2 g / 58.44 g/mol = 0.5176 mol of NaCl

Now, to prepare an aqueous solution with a concentration of 0.200 M, we need to determine the volume of solution needed. The formula for molarity can be rearranged to solve for volume:

Volume of solution (L) = number of moles of solute / Molarity (M)

Volume of solution = 0.5176 mol / 0.200 mol/L = 2.588 L

Therefore, we need 2.588 L of solution. Since the density of the solution is assumed to be the same as water, we know that 1 mL of water has a mass of 1 g, and the volume of water needed is:

2.588 L × 1000 mL/L = 2588 mL

Therefore, the total volume required by the chemist is 2588 mL.

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The element that is being reduced in the given redox reaction is Cl (Chlorine)

The given redox reaction is

Cr(OH)₄⁻(aq) + ClO⁻(aq) → CrO₄²⁻(aq) + Cl⁻(aq)

First, we will define the terms oxidation and reduction

Oxidation can be defined as an increase in oxidation number

Reduction is defined as a decrease in oxidation number

This means the element that is being reduced in the reaction would have a decrease in oxidation number.

Oxidation number of Cr in Cr(OH)₄⁻ is +3; and the oxidation number of Cr in CrO₄²⁻ is +6. This is an increase in oxidation number and it means Cr is being oxidized.

Oxidation number of Cl in ClO⁻ is +1; and the oxidation number of Cl in Cl⁻ is -1. This is a decrease in oxidation number and it means Cl is being reduced.

Hence, the element that is being reduced in the given redox reaction is Cl (Chlorine).

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Hello.

Magnesium nitrate is a chemical compound with the formula Mg (NO₃) ₂. Magnesium nitrate is an inorganic salt very soluble in water and alcohol and has the appearance of fine white crystals.

Magnesium Nitrate is commonly used as a fertilizer due to its high nutritional value, since it provides Magnesium and Nitrogen, these are important nutrients in the growth of crops. It is a water soluble fertilizer. Contains 10.5% N - 15.6% MgO. Provides nitrogen in the form of nitrate.

Answer:

21.16 MPa

Explanation:

Partial pressure of oxygen = 5.62 MPa

Total gas pressure = 26.78 MPa

But

Total pressure of the gas= sum of partial pressures of all the constituent gases in the system.

This implies that;

Total pressure of the system = partial pressure of nitrogen + partial pressure of oxygen

Hence partial pressure of nitrogen=

Total pressure of the system - partial pressure of oxygen

Therefore;

Partial pressure of nitrogen= 26.78 - 5.62

Partial pressure of nitrogen = 21.16 MPa

Answer:

The partial pressure of Nitrogen gas in the tank = 21.16 MPa.

Explanation:

According to Dalton's Law of partial pressure for gases, the total pressure of a mixture of gas under unchanging conditions is a sum of the partial pressures of each of the individual constituent gas.

The mixture consists of Nitrogen and oxygen gas. Hence, mathematically,

Total Pressure of the mixture = (Partial Pressure of Oxygen gas) + (Partial Pressure of Nitrogen gas)

Total Pressure of the mixture = 26.78 MPa.

Partial Pressure of Oxygen gas = 5.62 MPa.

Partial Pressure of Nitrogen gas = ?

26.78 = 5.62 + (Partial Pressure of Nitrogen gas)

Partial Pressure of Nitrogen gas = 26.78 - 5.62 = 21.16 MPa.

Hope this Helps!!!

Answer:

\(\%P/P_{hierro}=41.1\%\\\\\%P/P_{arena}=24.4\%\\\\\%P/P_{cobre}=30.8\%\\\\\%P/P_{aluminio}=0.6\%\)

Explanation:

¡Hola!

En este caso, dado que estamos tratando con problem sobre porcentaje peso/peso de hierro, arena, cobre y aluminio, primero debemos calcular la masa inicial de estos dos primeros en la mezcla original de acuerdo con:

\(m_{hierro}=300g*0.60=180g\\\\m_{arena}=300*0.40=120g\)

Ahora si podemos calcular la masa de la mezcla final como la suma de las masas de todos los constituyentes de la mezcla:

\(m_T=180g+120g+135g+2.77g=437.77g\)

Finalmente, podemos calcular los porcentajes P/P como se muestra a continuación:

\(\%P/P_{hierro}=\frac{180g}{437.77g} *100\%=41.1\%\\\\\%P/P_{arena}=\frac{120g}{437.77g} *100\%=24.4\%\\\\\%P/P_{cobre}=\frac{135g}{437.77g} *100\%=30.8\%\\\\\%P/P_{aluminio}=\frac{g}{437.77g} *100\%=0.6\%\)

¡Saludos!

Assessing the actual vs. ideal state of Old Spice's external search and internal search requires considering factors such as the brand's marketing efforts, information availability, online presence, customer reviews, and the overall consumer perception and loyalty towards the brand.

To evaluate the actual vs. ideal state of Old Spice's external search and internal search, we need to understand these concepts in the context of the brand and its marketing strategies.

External Search:

External search refers to the process by which consumers gather information from external sources to aid in their decision-making. In the case of Old Spice, the external search would involve consumers seeking information about Old Spice products, such as their features, benefits, pricing, availability, and customer reviews.

Actual State: The actual state of Old Spice's external search would depend on the effectiveness of its marketing efforts in providing readily available and easily accessible information to consumers. This could include advertising campaigns, product displays in stores, online presence, social media engagement, and customer reviews. The actual state would also be influenced by the brand's visibility and reputation among consumers.

Ideal State: The ideal state of Old Spice's external search would involve a comprehensive and user-friendly information ecosystem. This could include an informative and updated website, interactive online platforms, engaging social media presence, informative product descriptions, and positive customer reviews. The ideal state would aim to provide consumers with easy access to accurate and relevant information about Old Spice products, ultimately facilitating their decision-making process.

Internal Search:

Internal search refers to the process by which consumers draw upon their own knowledge and past experiences to evaluate and make decisions about a product or brand. In the context of Old Spice, internal search would involve consumers relying on their prior familiarity with the brand, its reputation, personal experiences with Old Spice products, and any pre-existing preferences or biases they may have.

Actual State: The actual state of Old Spice's internal search would depend on the brand's ability to create positive associations and experiences among consumers. It would also depend on the brand's efforts to maintain a consistent and recognizable image that consumers can recall and rely on during their decision-making process.

Ideal State: The ideal state of Old Spice's internal search would involve consumers having strong positive associations, experiences, and brand loyalty. This would mean that consumers readily recall their positive experiences with Old Spice products, have a favorable perception of the brand, and consider Old Spice as a preferred choice when evaluating similar products in the market.

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Surface model,we used a supercell of

16.1106×16.1106×18.0 And a model of a 3 × 3

9 atoms..

Answer:

devil's tango

Answer:

The beginning

Explanation:

In a nuclear reaction, the  rate of decay is fastest at the beginning of the process.

There are two types of nuclear reactions which are nuclear fusion and nuclear fission .They involve the combination and disintegration of the element's nucleus respectively.

In nuclear fission, the nucleus of the atom is bombarded with electrons of low energy which splits the nucleus in to two parts .Large amount of energy is released in the process.It is used in nuclear power reactors as it produces large amount of energy.

In nuclear fusion,on the other hand, is a reaction which occurs when two or more atoms combine to form a heavy nucleus.Large amount of energy is released in the process which is greater than that of the energy which is released in nuclear fission process.

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Answer:

Warmer air can hold more water vapor than colder air.

Explanation:

Weather can be defined as the atmospheric conditions of a particular area over a short period of time.

The elements of weather include precipitation, wind, temperature, atmospheric pressure, relative humidity, cloud, and wind speed.

Temperature can be defined as a measure of the degree of coldness or hotness of a physical object (body).

On the other hand, humidity refers to the concentration (amount) of water vapor that is present in the air. It is high when there's a lot of water vapor in the air and low when the level of water vapor is small.

The relationship between air temperature and humidity is that warmer air can hold more water vapor than colder air because as the air cools, its molecules move closer together while the molecules move farther apart as the air become hot.

Additionally, at constant humidity, relative humidity is inversely proportional to temperature i.e as the temperature decreases, relative humidity increases.

The neutral formula unit for the combination of calcium and NO₃⁻ is Ca(NO₃)₂. Calcium is a metal that belongs to group 2 of the periodic table, and it has a +2 charge. NO₃⁻ is a polyatomic ion that has a -1 charge.

When these two elements combine, they form an ionic compound through electrostatic attraction. The calcium cation and the nitrate anions combine in a 1:2 ratio to form the neutral compound Ca(NO₃)₂. This formula unit represents the simplest ratio of atoms in the compound and indicates that one calcium ion is combined with two nitrate ions.

So, the neutral formula unit for the combination of calcium (Ca) and nitrate (NO₃⁻) is Ca(NO₃)₂. In this compound, calcium has a charge of +2, while each nitrate ion has a charge of -1. To create a neutral formula unit, we need two nitrate ions for each calcium ion to balance the charges.

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Bromoethane and aqueous KOH reaction:

When a bromoethane is treated with aqueous KOH, one of the products of the reaction is a primary alcohol, ethanol.

The reaction:

CH3CH3Br + KOH (aq) ==> CH3CH2OH + KBr