How many joules must be added to a 1000 g iron skillet to increase its temperature
from 25°C to 250°C? The specific heat of iron is 0.449 J/gºC.
A) 449 J
B) 101,025 J
C) 50,000 J
D) 112,250 J

Answer:

c

Explanation:

8.4

For the reaction H₂SO₄ + 2NaC≡N → 2HC≡N + Na₂SO₄, we have that 8.4 moles of sodium cyanide are needed to produce 4.2 moles of sodium sulfate (option C).

The reaction between sodium cyanide and sulfuric acid is:  

H₂SO₄ + 2NaC≡N → 2HC≡N + Na₂SO₄

We can find the number of moles of sodium cyanide, assuming that it is the limiting reactant and knowing that 2 moles of it produce 1 mol of sodium sulfate, as follows:  

[tex] n_{NaC\equiv N} = \frac{2\: moles\: NaC\equiv N}{1 \: mol\: Na_{2}SO_{4}}*4.2 \: moles\: Na_{2}SO_{4} = 8.4 \: moles [/tex]  

Therefore, 8.4 moles of sodium cyanide are needed to produce 4.2 moles of sodium sulfate (option C).  

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Answer:

the answer for your question is veins

Answer:

blood vessels aka veins

Number of moles = 78.41

The mole is the number of particles(molecules, atoms, ions) contained in a substance  

1 mol = 6.02.10²³ particles

Can be formulated

N=n x No

N = number of particles

n = mol

No = Avogadro's = 6.02.10²³

4.72 x 10²⁵ atoms of a substance, then moles :

[tex]\tt n=\dfrac{N}{No}\\\\n=\dfrac{4.72\times 10^{25}}{6.02\times 10^{23}}\\\\n=78.41[/tex]

Answer:

No-till conservation tillage

Explanation:

No till conservation involves the soil not being touched which gives rise to a large amount of organic matter being left on the surface.

The Advantage of this method is that it helps to prevent erosion such as that of wind and water due to the little or no exposure of the soil surface and helps to provide nutrients to the plants through the organic matter present.

The Disadvantage of this method is its heavy reliance of chemicals such as herbicides in killing the weeds in order to prevent competition for vital compounds with the main plants.

Answer:

Speed is how fast you cover a certain distance

[tex]Speed=\frac{Distance}{time}[/tex]

Answer:

Fluorine-18

Explanation:

An isotope is an element with different amounts of neutrons.  The element itself will not change.

Answer: I believe that it is that the forces are balanced.

Explanation:

1. LDFs

2. Intermolecular Forces

3. Intramolecular Forces

4. Linear

5. Tetrahedral

Edit: I'm new to this site and idk how to use it properly. I'm not sure about 2 and 3 currently because these forces are between molecules as well so INTERmolecular would be used twice (?)

Answer:

Compounds

Explanation:

All compounds of a substance shares chemical bonds between them and their structures.

The bonds can come in different forms. Compound are held by chemical bonds within their atoms.

Answer:

See explanation

Explanation:

Now we have, the graph attached.the stable disintegration product of C-14 is N-14.

Then;

Since the mass of C-14 originally present is 64g, at a time t= 17100 years, we will have;

N/No = (1/2)^t/t1/2

N = mass of C-14  at time t

No= mass C-14 originally present

t = time taken for  N amount of C-14 to remain

No = mass of C-14 originally present

t1/2 = half life of C-14

N/64 = (1/2)^17,100/5730

N/64 = (1/2)^3

N/64 = 1/8

8N = 64

N = 8 g

Answer:

See below!

Explanation:

Translocation  ⇒  CCGGTT + TTAGGC = CCGGTA + GTTGGC

A translocation is a change in location between two chromsomes.

Inversion  ⇒  CTTAAT = TAATTC

An inversion is when a gene is flipped.

Deletion  ⇒  CGAGGTT = CGTT

A deletion is when a part of gene is deleted.

Duplication  ⇒  ATTCGG = ATTCGGATTCGG

A duplication is when a gene is duplicated.

Insertion  ⇒  CTTAAT = CTTAACGCT

An insertion is when nucleotide bases are inserted into a gene.

Substitution  ⇒  CGAT = CTAT

A substitution is when part of a gene is replaced with a different base pair.

Answer:

2 C Atoms

Explanation:

When you have coefficient of 2 next to a compound element, it indicates there are 2 of each compound element. In the compound element, there is one C Atom, and 2×1 is 2.

Answer:

NaF

Explanation:

Melting point of NaF is 993°C but Melting point of KF is 858°C

Answer:

I think naf

Explanation:

Answer:

a) The heat energy absorbed to heat the solid is approximately 58.8 kJ

b) The heat required to melt the solid is approximately 3.93 kJ

c) The heat required to heat the liquid is approximately 29.2 kJ

d) The total amount of energy, absorbed in the entire process is approximately 92 kJ

Explanation:

a) The given parameters are;

The mass of the substance = 488.3 grams

The molar mass of the sample = 92.41g/mol

The temperature change of the substance = -23.1°C to 51.8 °C

The heat capacity of the solid substance = 2.96 J/(g·°C)

The heat capacity of the liquid substance = 1.75 J/(g·°C)

ΔHfus = 8.04 kJ/mol

Taking the melting point temperature of the solid as Tfinal = 17.6 °C, we have;

The heat energy absorbed to heat the solid, Q₁ = 488.3 × 2.96 × (17.6 - (-23.1)) = 58826.4776 J ≈ 58.8 kJ

b) The heat required to melt the solid, Q₂ = ΔHfus × m = 8.04 × 488.3 = 3925.932 J ≈ 3.93 kJ

c) The heat required to heat the liquid, Q₃ = Mass × The specific heat capacity of the liquid × The change in temperature

Therefore;

Q₃ = 488.3 × 1.75 × (51.8 - 17.6) = 29224.755 J ≈ 29.2 kJ

d) The total amount of energy, absorbed in the entire process, ΔQ, is given as follows;

ΔQ = Q₁ + Q₂ + Q₃ = 58826.4776 J + 3925.932 J + 29224.755 J = 91,977.1646 J ≈ 92 kJ

Answer:

Ooo gas laws! fun! the answer is B, 1600 kPa

Explanation:

Here are some key things to remember:

- to convert Celsius to Kelvin add 273

The heat required : 840 J

Given

mass of water = 20 g

Temperature : 30°C to 40°C

Required

Heat to raise the temperature

Solution

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  (for water= 4.18 J/g° C)

∆T = temperature difference, ° C / K  

The heat :

[tex]\tt Q=20\times 4.2\times (40-30)\\\\Q=\boxed{\bold{840~J}}[/tex]

Answer:

I think the answer is 11.190% :)

Explanation:

Hope this helps <3

Explanation:

It is given that,

A football player has to run 60 meters in 5 seconds or less in order to make the all-star team.

We need to find the slowest speed he run in order to qualify for the all-star team. Let it is v. It can be calculated as follows :

v = d/t

= 60 m/5 s

= 12 m/s

It means his slowest speed is 12 m/s and he should increase his speed in order to qualify for the all-star team.

Answer:

A través del Experimento de Rutherford.

Explanation:

El experimento de la lámina de oro fue realizado en 1909 por Ernest Marsden y Hans Geiger bajo el liderazgo de Ernest Rutherford. En este experimento, se bombardeó una lámina de oro con partículas alfa y se detectó su dispersión. Se encontró que una pequeña proporción de las partículas regresan cerca de la fuente. Estos resultados fueron la base para el lanzamiento de un nuevo modelo atómico con un núcleo central cargado positivamente y con electrones cargados negativamente con pequeñas masas en relación con el núcleo y distribuidos a su alrededor.

Answer:

mass = 78 grams

volume= 2*5*6=60cm^3

density =m/v

=78/60

13/10=1.3 g/cm^3

Explanation:

The mass of the block of metal would be 780 grams

The volume of the block of metal would be  60 centimeter³

The density of the block of the metal is 13 g/cm³

It can be defined as the mass of any object or body per unit volume of the particular object or body. Generally, it is expressed as in gram per cm³ or kilogram per meter³.

The density is the reciprocal of the specific volume of any substance.

ρ =m /v

As given in the problem a block of metal has dimensions of 2 cm by 5 cm by 6 cm. The block weighs 780 grams

The volume of the block of metal would be  = 2×5×6 centimeter³

                                                                         = 60 centimeter³

The mass of the block of metal = 780 grams

ρ =m /v

ρ = 780 /60 gram/ cm³

ρ = 13 g/cm³

Thus, the mass volume and the density of the block of the metal would be  780 grams , 60 centimeter³, and 13 g/cm³ respectively.

To learn more about density from here, refer to the link ;

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Answer:

Error or mistakes during DNA replication is accountable for two-thirds or 66% of the cancer cases. These random and unpredictable errors called mutations that occur during the division of a cell as an error in copying of DNA.

DNA replication has three main steps:

Opening and separation of DNA strands of a helix - carried by an enzyme known as helicase that breaks the hydrogen bonds between nitrogenous bases of the helix of DNA.

The priming of the template strand - DNA primase helps RNA primers to bind to both strands at 3' end as soon as it separated

strat assembling the segments of new DNA on strands called elongation of the strands with help DNA polymerase I and after forming new strands the termination of the replication.

Errors or mistakes can occasionally take place if DNA polymerase inserts a wrong base during elongation of the strands.

Answer:

B) number of electrons

Explanation:

The two species:

          K+   and Cl- have the same number of electrons.

A neutral atom of K has 19 electrons

A neutral atom of Cl has 17 electrons

Now,

 To form K+, K will have to lose an electron and then the number of electrons becomes 18

To form Cl-, Cl will have to gain an electrons and then the number of electrons becomes 18

So, therefore, the number of electrons on both species is 18

Answer:

C

Explanation:

In the bone marrow, red blood cells are produced

Answer:

The answer is a) [tex]C_{4} H_{16} O_{5}[/tex]

Explanation:

The other chemical formulas' subscripts share a common factor, so they can be simplified to an empirical formula, however, the subscripts in  [tex]C_{4} H_{16} O_{5}[/tex] cannot be simplified any further, because they do not share any more whole-number factors with each other.

Answer:

(D) greater than the energy stored in the bonds of the products.

Explanation:

Exothermic reaction refer to those reactions in which energy is released to the surrounding, unlike endothermic reactions where energy is absorbed from the surroundings.

In exothermic reactions, the change in energy; ΔH less than zero. That is, they are negative.

ΔH = H (products) - H (reactants)

For ΔH to have a negative value, it means the energy of reactant must be greater than the energy of products.

This means the correct option is;

(D) greater than the energy stored in the bonds of the products.

In an exothermic reaction the energy of the reactants bonds has been higher than the energy of the product bonds. Thus, option D is correct.

The exothermic reaction has been given as the chemical reaction in which there has been the liberation of energy by the reactants in the process of formation of products.

The energy change in the reaction has been a negative value. In the process of product formation, the energy of the system has been conserved. It stated that the energy of the reactant has been equivalent to the energy of the product and the liberated energy.

With the product being consisted of less energy, the energy stored by the chemical bonds in the reactants has been higher than the energy stored by the product. Thus, option D is correct.

For more information about the exothermic reaction, refer to the link:

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