whats a Natural Selection?

Answer:

no, and next time take it right

Explanation:

Answer: 1and 4

Explanation: iron is an element not an alloy. An ionic lattice is not bonded covalently.

Answer:

The expression to calculate the number of moles reactants is:

n = 59.714 J / 368000 J/mole

Explanation:

Note: The question is missing some parts. The complete question is as follows:

A certain chemical reaction releases 368.kJ of heat energy per mole of reactant consumed. Suppose some moles of the reactant are put into a calorimeter (a device for measuring heat flow). It takes 4.09J of heat energy to raise the temperature of this calorimeter by 1°C. Now the reaction is run until all the reactant is gone, and the temperature of the calorimeter is found to rise by 14.6°C. How would you calculate the number of moles of reactant that were consumed?

Set the math up. But don't do any of it. Just leave your answer as a math expression.

Also, be sure your answer includes all the correct unit symbols.

Step 1: Determine the quantity of heat required to raise the temperature of the calorimeter by 14.6°C

Quantity of heat required to raise the temperature of the calorimeter by 1°C = 4.09 J

Quantity of heat required to raise the temperature of the calorimeter by 14.6°C = 4.09 * 14.6 = 59.714 J

Step 2: Express the quantity of heat released per mole of reactant in J/mole

368 kJ/mole = 368 kJ/mole * 1000 J/kJ = 368000 J/mole

Step 3: Express the moles of reactant as n and equate it to the energy absorbed by the calorimeter

Let the number of moles of reactant be n

Assuming that there is no heat lost to the surrounding, from the law of conservation of energy, Heat released = Heat absorbed

Heat released = number of moles of reactant * quantity of heat released per mole of reactant

Heat released = n * 368000 J/mole

Heat absorbed by calorimeter = 59.714 J

From the relation above, n * 368000 J/mole = 59.714 J

n = 59.714 J / 368000 J/mole

Therefore, the expression to calculate the number of moles is n = 59.714 J / 368000 J/mole

Answer:

definite volume

Explanation:

Both solids and liquids have a definite volume: The difference is that solids have definite shape while liquids do not -liquids take the shape of their containers-.

Having a definite volume is why liquids cannot be compressed, a property that is used in hydraulic systems.

Answer:

323.22 ml

Explanation:

Given that :

Diameter, d = 6.8cm

Height, h = 8.9cm

V = arh

Recall :

Volume, V = πr²h

Radius, r = diameter / 2 = 6.8 / 2 = 3.4cm

V = π * 3.4^2 * 8.9

V = 323.21961 cm³

Recall:

1ml = 1cm³

Hence,

323.21961 cm³ = 323.21961 ml

Volume = 323.22 ml

Mass of iron(ll) oxide= 616.608 g

Given

Reaction

2Fe+O2 -->2FeO

479.6 grams of iron

Required

mass of iron(ll) oxide

Solution

mol of iron :

= mass : Ar Fe

= 479.6 g : 56 g/mol

= 8.564

From the equation, mol FeO :

= 2/2 x mol Fe

= 2/2 x 8.564

= 8.564 moles

Mass of iron(ll) oxide :

= mol x MW

= 8.564 x 72 g/mol

= 616.608 g

If one DNA strand reads CCGTAATGCAT, the sequence of the complementary strand will be - b) GGCATTACGTA

So, DNA strand -                        C-C-G-T-A-A-T-G-C-A-T

Complementary DNA strand -  G-G-C-A-T-T-A-C-G-T-A

Thus, If one DNA strand reads CCGTAATGCAT, the sequence of the complementary strand will be - b) GGCATTACGTA

Learn more:

https://brainly.com/question/3372278

Answer:

1)40n

2)25n

Explanation:

subtract the numbers if its on the opposite sides and add if its on same side

thank u hope it helps

Answer:

There are two atoms in one hydrogen molecule.

Explanation:

Hello!

In this case, when going over chemical reactions, we need to realize about the amount of atoms of each element; thus, according to the given chemical reaction by which water is formed:

[tex]H_2+O_2\rightarrow H_2O[/tex]

It is seen there are two hydrogen atoms in the hydrogen molecule, two in oxygen and two hydrogen atoms and one oxygen atom in water; however, these reactions must be balanced according to the law of conservation of mass:

[tex]2H_2+O_2\rightarrow 2H_2O[/tex]

Which means we have two hydrogen molecules with two atoms each, one oxygen molecule with two atoms and two water molecules with two hydrogen atoms and one oxygen atom each.

Best regards!

Answer:

It uses this term to represent the economic use of land and nature, with minimal degradation and maximum environmental preservation.

Explanation:

Capitalism is an economic system that promotes the maximum economic exploitation of terrestrial resources. It is common for this exploitation to be strongly associated with environmental degradation, destruction of natural habitats, deforestation and death of fauna and flora. With this, we can consider that capitalism is one of the main formulators of environmental degradation, however many professionals have considered the term "capitalism mated with conservation," where terrestrial resources are exploited consciously and with the objective of reducing degradation to the maximum. environmental impact and maximize conservation.

Answer: soaps are a sodium or potassium salts of long chain fatty acids.when triglycerides in fat/oil react with aqueous NaOH or KOH,they are converted into soap and glycerol.This is called alkaline hydrolysis of esters.Since this reaction leads to formation of soap, it is called the saponification process.

Explanation:

Answer:

The answer is "[tex]= 0.078 \ kg \ H_2[/tex]".

Explanation:

calculating the moles in [tex]CH_4 =\frac{PV}{RT}[/tex]

                                                [tex]=\frac{(0.58 \ atm) \times (923 \ L) }{ (0.0821 \frac{L \cdot atm}{K \cdot mol})(232^{\circ} C +273)}\\\\=\frac{(535.34 \ atm \cdot \ L) }{ (0.0821 \frac{L \cdot atm}{K \cdot mol})(505)K}\\\\=\frac{(535.34 \ atm \cdot \ L) }{ (41.4605 \frac{L \cdot atm}{mol})}\\\\= 12.9 \ mol[/tex]

Eqution:

[tex]CH_4 +H_2O \to 3H_2+ CO \ (g)[/tex]

Calculating the amount of [tex]H_2[/tex] produced:

[tex]= 12.9 \ mol CH_4 \times \frac{3 \ mol \ H_2 }{1 \ mol \ CH_4}\times \frac{2.016 g H_2}{1 \ mol \ H_2}\\\\= 78 \ g \ H_2 \\\\= 0.078 \ kg \ H_2[/tex]

So, the amount of dihydrogen produced = [tex]0.078 \frac{kg}{s}[/tex]

Answer:

a period

Explanation:

Answer: The row of elements across the periodic table is called "periods".

Explanation:

In the Periodic Table, there are seven rows of elements, which is called periods.

Answer:

the lattice constant is 0.270 inches

Explanation:

Given the data in the question;

For FCC lattice;

a = b = c, ∝ = β = α = 90°

from the image below;

AC = 0.19 + 0.19/2 + 0.19/2 + 2(0.001) inch

AC = 0.19 + 0.095 + 0.095 + 0.002

AC = 0.382 inches

Now using Pythagoras theorem

AC² = AB² + BC²

since a = b = c

AC² = a² + a²

(0.382)² = 2a²

2a² = 0.145924

a² = 0.145924 / 2

a² = 0.072962

a = √0.072962

a =  0.27011 ≈ 0.270 inches

Therefore, the lattice constant is 0.270 inches

Answer:

237.5 grams CaCl2

Explanation:

Use the periodic table to calculate the mass of CaCl2

40.078+(35.45*2)=110.97800

Convert: 2.14 mol CaCl2 * 110.98g CaCl2/1 mol CaCl2 = 237.4972 g

Answer:

Formulas

3.2 Determining Empirical and Molecular Formulas

Learning Objectives

By the end of this section, you will be able to:

Compute the percent composition of a compound

Determine the empirical formula of a compound

Determine the molecular formula of a compound

The previous section discussed the relationship between the bulk mass of a substance and the number of atoms or molecules it contains (moles). Given the chemical formula of the substance, one may determine the amount of the substance (moles) from its mass, and vice versa. But what if the chemical formula of a substance is unknown? In this section, these same principles will be applied to derive the chemical formulas of unknown substances from experimental mass measurements.

Percent Composition

The elemental makeup of a compound defines its chemical identity, and chemical formulas are the most succinct way of representing this elemental makeup. When a compound’s formula is unknown, measuring the mass of each of its constituent elements is often the first step in the process of determining the formula experimentally. The results of these measurements permit the calculation of the compound’s percent composition, defined as the percentage by mass of each element in the compound. For example, consider a gaseous compound composed solely of carbon and hydrogen. The percent composition of this compound could be represented as follows:

%H=mass Hmass compound×100%

%C=mass Cmass compound×100%

If analysis of a 10.0-g sample of this gas showed it to contain 2.5 g H and 7.5 g C, the percent composition would be calculated to be 25% H and 75% C:

%H=2.5g H10.0g compound×100%=25%

%C=7.5g C10.0g compound×100%=75%

EXAMPLE 3.9

Calculation of Percent Composition

Analysis of a 12.04-g sample of a liquid compound composed of carbon, hydrogen, and nitrogen showed it to contain 7.34 g C, 1.85 g H, and 2.85 g N. What is the percent composition of this compound?

Solution

To calculate percent composition, divide the experimentally derived mass of each element by the overall mass of the compound, and then convert to a percentage:

%C=7.34g C12.04g compound×100%=61.0%%H=1.85g H12.04g compound×100%=15.4%%N=2.85g N12.04g compound×100%=23.7%

The analysis results indicate that the compound is 61.0% C, 15.4% H, and 23.7% N by mass.

Check Your Learning

A 24.81-g sample of a gaseous compound containing only carbon, oxygen, and chlorine is determined to contain 3.01 g C, 4.00 g O, and 17.81 g Cl. What is this compound’s percent composition?

ANSWER:

12.1% C, 16.1% O, 71.8% Cl

Determining Percent Composition from Molecular or Empirical Formulas

Percent composition is also useful for evaluating the relative abundance of a given element in different compounds of known formulas. As one example, consider the common nitrogen-containing fertilizers ammonia (NH3), ammonium nitrate (NH4NO3), and urea (CH4N2O). The element nitrogen is the active ingredient for agricultural purposes, so the mass percentage of nitrogen in the compound is a practical and economic concern for consumers choosing among these fertilizers. For these sorts of applications, the percent composition of a compound is easily derived from its formula mass and the atomic masses of its constituent elements. A molecule of NH3 contains one N atom weighing 14.01 amu and three H atoms weighing a total of (3 × 1.008 amu) = 3.024 amu. The formula mass of ammonia is therefore (14.01 amu + 3.024 amu) = 17.03 amu, and its percent composition is:

%N=14.01amu N17.03amuNH3×100%=82.27%%H=3.024amu H17.03amuNH3×100%=17.76%

This same approach may be taken considering a pair of molecules, a dozen molecules, or a mole of molecules, etc. The latter amount is most convenient and would simply involve the use of molar masses instead of atomic and formula masses, as demonstrated Example 3.10. As long as the molecular or empirical formula of the compound in question is known, the percent composition may be derived from the atomic or molar masses of the

Answer:

Option A is correct.

Option D is correct.

E is the correct answer

Explanation:

This a theoretical calorimetry problem that can be solved by thermodynamic concepts.

Our system is the unknown solid. If the temperature of water has increased, we can think, that the heat from the metal was absorbed by water, which is our surrounding. If in the analysis of the situation we use a calorimeter, knowing that it is an isolated system, which does not allow the entry or exit of heat, we can conclude that the heat released is equal to the heat absorbed.

In conclusion, the thermodynamic system is constituted by the chemical reaction. In this case, the surrounding is made up of water and the calorimeter itself.

Answer:

Xb = 0.59

Explanation:

Let's analyze the given data.

We have a total vapor pressure of 263 Torr for the mix of the two gases. And the individual vapour pressures for each gas is given, and it's 425 Torr for pentane and 151 Torr for hexane.

We are asked to determine the mole fraction of hexane. For practical purposes, we will label pentane as "a" while hexane would be "b". So, let's write the equations that we need to calculate this.

We know that the total pressure of a solution would be:

P = Pa + Pb    (1)

And we also know that these individual pressures are:

Pa = Xa * Pa°    (2)

Pb = Xb * Pb°    (3)

Where Pa° and Pb° are the vapour pressures of each gases.

The mole fractions (Xa and Xb), can be expressed, one in function of the other:

Xa + Xb = 1 -----> Xa = 1 - Xb     (4)

Now that we know this, we can replace (4) in (2), and then, (2) and (3) can be replaced in (1):

Pa = (1 - Xb)Pa°

P = (1 - Xb)Pa° + XbPb°      (5)

Replacing the given data, we have:

263 = (1 - Xb)*425 + 151Xb

Now solving for Xb, which is the mole fraction of hexane:

263 = 425 - 425Xb + 151Xb

263 - 425 = (-425 + 151)Xb

-162 = -274Xb

Xb = -162 / -274

Hope this helps

Answer:

  58.0 g/mol

Explanation:

At STP, one mole occupies 22.4 liters. One mole of the hydrocarbon would have a mass of ...

  (2.59 g/L)(22.4 L/mol) ≈ 58.0 g/mol

Answer:

Answer:

44.45 g of tetrahydrofuran.

Explanation:

From the question given above, the following data were obtained:

Volume of tetrahydrofuran = 50 mL

Density of tetrahydrofuran = 0.889 g/mL

Mass of tetrahydrofuran =?

Density of a substance is simply defined as the mass of the substance per unit volume of the substance. Mathematically, density is expressed as shown below:

Density = mass / volume

With the above formula, we shall determine the mass of tetrahydrofuran needed. This can be obtained as follow:

Volume of tetrahydrofuran = 50 mL

Density of tetrahydrofuran = 0.889 g/mL

Mass of tetrahydrofuran =?

Density = mass / volume

0.889 = mass / 50

Cross multiply

Mass = 0.889 × 50

Mass of tetrahydrofuran = 44.45 g

Therefore, the student should weigh out 44.45 g of tetrahydrofuran.

Answer:

The correct answer is A :))

Answer: Thermal Equilibrium

Explanation:

Answer:

temperature  

Explanation:

I think that's it i'm sorry if i'm wrong

Answer:

Kp = Kc (RT) ^(-2)

Explanation:

For the reaction;

N2 (g) + 3H2 ⇄ 2NH3(g)

We can write;

Kc = [NH3]^2/[N2] [H2]^3

But

Kp = pNH3^2/pN2 . PH2^3

To convert from Kc to Kp

Kp = Kc (RT) ^Δn

where Δn is the change in number of moles going from reactants

to products.

For this reaction;

Δn = 2- (3+1) = -2

Kp = Kc (RT) ^(-2)

Answer:

298. 7 K.

Explanation:

Hello!

In this case, since equation we use to compute the heat in a cooling or heating process is:

[tex]Q=mC(T_f-T_i)[/tex]

Whereas we are given the heat, mass, specific heat and initial temperature. Thus, we infer that we need to solve for the final temperature just as shown below:

[tex]T_f=T_i+\frac{Q}{mC}\\\\T_f=1000 K+\frac{-270000J}{1000g*0.385\frac{J}{g*K} } \\\\T_f=298.7 K[/tex]

It is important to notice that the iron release heat as water absorbs it, that is why it is taken negative.

Best regards!

Answer:

It is D !!

Explanation:

Just did test

Answer:

[tex]\frac{3}{2}He[/tex]

[tex]\frac{6}{2} He[/tex]

[tex]\frac{7}{4}Be[/tex]

[tex]\frac{3}{1} H[/tex]

[tex]\frac{6}{4}Be[/tex]

[tex]\frac{7}{3} Li[/tex]

Explanation:

In the first nucleus we are told that there are two protons and one neutron. Let us remember that the mass number = number of protons + number of neutrons.

This implies that, for the first specie the mass number is 3, for the second specie the mass number is 6 and the third specie has a mass number of 7 and so on. The mass number is indicated as a superscript.

The atomic number is the number of protons in the nucleus of the atom and helps us to identify the atom. It is always written as a subscript as shown.

458 g H₂SO₄

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Stoichiometry

Step 1: Define

4.67 mol H₂SO₄

Step 2: Identify Conversions

[PT] Molar Mass of H - 1.01 g/mol

[PT] Molar Mass of S - 32.07 g/mol

[PT] Molar Mass of O - 16.00 g/mol

Molar Mass of H₂SO₄ - 2(1.01) + 32.07 + 4(16.00) = 98.09 g/mol

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

458.08 g H₂SO₄ ≈ 458 g H₂SO₄

Answer:

the answer p+n

Explanation:

Answer:

4.82 moles of Ag.

Explanation:

We'll begin by calculating the number of mole in 450.98 g of Cu(NO₃)₂. This can be obtained as follow:

Molar mass of Cu(NO₃)₂ = 63.5 + 2[14 + (16×3)]

= 63.5 + 2[14 + 48]

= 63.5 + 2[62]

= 63.5 + 124

= 187.5 g/mol

Mass of Cu(NO₃)₂ = 450.98 g

Mole of Cu(NO₃)₂ =?

Mole = mass /Molar mass

Mole of Cu(NO₃)₂ = 450.98 / 187.5

Mole of Cu(NO₃)₂ = 2.41 moles

Next, we shall determine the number of mole of Cu needed to produce 450.98 g (i.e 2.41 moles) of Cu(NO₃)₂. This can be obtained as follow:

Cu + 2AgNO₃ —> Cu(NO₃)₂ + 2Ag

From the balanced equation above,

1 mole of Cu reacted to produce 1 mole of Cu(NO₃)₂.

Therefore, 2.41 moles of Cu will also react to produce 2.41 moles of Cu(NO₃)₂.

Thus, 2.41 moles of Cu is needed for the reaction.

Finally, we shall determine the number of mole of Ag produced from the reaction. This can be obtained as follow:

From the balanced equation above,

1 mole of Cu reacted to produce 2 moles of Ag.

Therefore, 2.41 moles of Cu will react to produce = 2× 2.41 = 4.82 moles of Ag.

Thus, 4.82 moles of Ag were obtained from the reaction.