Which of the following elements has three valence electrons? (2 points)

Li
C
Al
Mg

Answer:

its a chemical change.

hope it helps.

Answer: it is a chemical change because it involves chemical process

Explanation:

Answer:

Which of these will form hydrogen bonds?

a. CH2Br2

b. CH3OCH2CH3

c. H2NCH2COOH

d. H2SO3

e. CH3CH2OH

Explanation:

A hydrogen bond is the weak electrostatic force of attraction that exists between a covalently bonded hydrogen atom and a highly electronegative atom like N,O, and F.

For example, water has a hydrogen bond between the hydrogen atoms of one molecule and the oxygen atom of another molecule.

Among the given molecules,

a. CH2Br2 does not have a hydrogen bond because it does not have N or O or F.

b. CH3OCH2CH3 does not have a hydrogen bond.

Due to the absence of -OH or -NH or H-F bonds.

c. H2NCH2COOH  shows hydrogen bonding.

d. H2SO3 has hydrogen bonding.

Due to the presence of -OH bond.

e. CH3CH2OH has hydrogen bonding.

Due to the presence of -OH bond.

Answer:

[tex]\boxed {\boxed {\sf 0.601 \ g \ As}}[/tex]

Explanation:

We want to convert atoms of arsenic to mass in grams. We have to complete 3 steps.

The first step is converting atoms to moles. We use Avogadro's Number for this. This number is 6.022*10²³ and it is the number of representative units (molecules, atoms, etc.) in 1 mole of a substance. In this problem, the particles are atoms of arsenic. So, 1 mole of arsenic contains  6.022*10²³ atoms of arsenic. Use this information to make a ratio.

[tex]\frac{1 \ mol \ As}{{6.022*10^{23} \ atoms \ As} }[/tex]

Multiply by the number of atoms provided in the problem: 4.83 × 10²¹

[tex]4.83 *10^{21} \ atoms \ As *\frac{1 \ mol \ As}{{6.022*10^{23} \ atoms \ As} }[/tex]

The units of atoms of arsenic (atoms As) cancel.

[tex]4.83 *10^{21} *\frac{1 \ mol \ As}{{6.022*10^{23}} }[/tex]

Condense into 1 fraction.

[tex]\frac{4.83 *10^{21} }{{6.022*10^{23}} } \ mol \ As[/tex]

[tex]0.008020591166 \ mol \ As[/tex]

The next step is converting moles to grams. We use the molar mass for this, which is provided. There are 74.92 grams of arsenic in 1 mole of arsenic, so we can make another ratio.

[tex]\frac {74.92 \ g\ As}{ 1 \ mol \ As}[/tex]

Multiply by the number of moles we calculated.

[tex]0.008020591166 \ mol \ As*\frac {74.92 \ g\ As}{ 1 \ mol \ As}[/tex]

The units of moles of arsenic (mol As) cancel.

[tex]0.008020591166 *\frac {74.92 \ g\ As}{ 1}[/tex]

[tex]0.6009026901 \ g \ As[/tex]

The original measurement of atoms (4.83 × 10²¹ ) has 3 significant figures, so our answer must have the same.

For the number we calculated, that is the thousandth place. The 9 in the ten-thousandth place (0.6009026901) tells us to round the 0 to a 1.

[tex]0.601 \ g \ As[/tex]

There are approximately 0.601 grams of arsenic.

Answer:

This is the chemical formula for calcium phosphate:

[tex]Ca_3(PO_4)_2[/tex].

Calculate the mass percent of oxygen in calcium phosphate. Round your answer to the nearest percentage

Explanation:

The molar mass of calcium phosphate is: 310.18g/mol.

In one mole of calcium phosphate there are 8 moles of oxygen atoms.

The atomic mass of oxygen in calcium phosphate is: 128.0 g

Hence, the mass % of oxygen in the given compound is:

[tex]mass% of Oxygen =\frac{mass of oxygen}{mass of calcium phosphate}*100\\&=\frac{128.0g}{310.18g} *100\\&=41.3[/tex]

Hence,mass%of oxygen is 41.3.

Answer:

Explanation:

Because you only have one repeat unit, n=1. 2n-1 becomes 2(1)-1 which is equal to one, meaning one molecule of H2O is produced, as is shown by the top condensation polymerisation reaction.

If you had two repeat units, n=2 so 2n-1=3. Three H2O molecules are produced because you would need two molecules of each reactant so three condesation reactions would occur and three molecules of H2O would be released.

Answer:

carbon

Explanation:

because it is an allotrope of carbon

Answer:

Carbon

Explanation:

its literaly carbon

Answer:

3.36×10²⁶ g

Explanation:

Molar mass ( O2) = 32g/mol

mole(O2) = 1.05×10²⁵mol

Mass(O2) = ?

mole(n)= mass(m)/Molar mass(M)

n×M = m

1.05×10²⁵ mol × 32g/mol = mass

mass= 3.36×10²⁶ g

Answer:

The average atomic mass includes all of the isotopes of that atom which exist in nature. Almost all elements have at least two isotopes which naturally occur. Recall that isotopes are atoms with the same atomic number (protons), but a different number of neutrons.

Temperature change

Answer: The answer is D:

Answer:

The answer is Option D

Answer:

heat mixture/stir

Explanation:

these are factors of dissolving of solvent faster

1st one

2_2_2

2nd one

3_1_1_3

i looked it up

Answer:

no pues nadie te pasa la pagina

Answer:

1. How do metals and non-metals react with acids?

Ans : Non metals does not react with acids while metals react with acids and produce hydrogen gas that burns with a 'pop'sound.

2. Write and explain the chemical equation for the reaction of magnesium with sulphuric acid and aluminium with hydrochloric acid.

Magnesium + sulphuric acid = Hydrogen + salt

Mg(s) + H2SO4 (aq) MgSO 4(aq) +H2 (g)

Aluminium + Hydrochloric acid = Hydrogen + Aluminium chloride

2Al(s)+6HCl(aq)→2AlCl3(aq)+3H2(g)

Answer:

Metals react with acid but non metals donot react with acid because

when a substance, reacts with acids it provides electrons to the H+ ions produced by the acids. Non-metals are acceptors of electrons and hence, they cannot donate electrons.

Explanation: H2SO4 + Mg(OH)2 = H2O + MgSO4. 2Al+6HCl→2AlCl3+3H2 2 A l + 6 H C l → 2 A l C l 3 + 3 H 2

m=y2 −y1/x2-x1

Explanation:

3-5/2-12=1/5

Answer:

overall I think one answer

Answer:

This answer I think it is Al,F

Answer:

the answer is c kept in blue and with light

Answer: the basic difference is Exergonic reactions release energy and an endergonic reactions absorb energy .

HOPE THIS HELPS!!!

Answer:

Inference

Explanation:

I mean, it's not difficult.

A theory is an unproven explanation.

An inference is a guess/educated guess where you don't have all the facts.

For example, if "Bob" is caught in the kitchen with a ketchup stain on his shirt, you are inferencing that he used the ketchup.

However, if you see a ketchup bottle nearby or saw it earlier, then it is not, because you already have the facts that ketchup was used.

Answer:

5 kg of feather

Explanation:

Answer:

sorry i dint understand can u ask it in a simpler way

Explanation:

Answer:

[tex]\boxed {\boxed {\sf 79,420 \ J}}[/tex]

Explanation:

We are given the mass, a change in temperature, and the specific heat of water. We should use the following formula to solve this problem.

[tex]q=mc\Delta T[/tex]

In this formula, m is the mass, c is the specific heat, and ΔT is the change in temperature.

We know there are 250 grams of water and the specific heat of water is 4.18 J/g · °C.

We are given two temperature, so have to find the change in temperature. This is the difference between the initial temperature and final temperature. The water is heated from 24 °C to 100 °C. Therefore, the initial is 24 and the final is 100.

[tex]\bullet \ \Delta T= T_{final} - T_{initial} \\\bullet \ \Delta T=100 \textdegree C - 24 \textdegree C\\\bullet \Delta T= 76 \textdegree C[/tex]

Now we know all three of the variables and we can substitute them into the formula.

[tex]\bullet \ m= 250 \ g\\ \bullet \ c=4.18 \ J/g \textdegree C \\ \bullet \ \Delta T= 76 \textdegree C[/tex]

[tex]q= (250 \ g)( 4.18 \ J/g * \textdegree C)( 76 \textdegree C)[/tex]

Multiply the first two numbers together. The units of grams will cancel.

[tex]q= (1045 \ J/\textdegree C)(76 \textdegree C)[/tex]

Multiply again. This time, the units of degrees Celsius cancel.

[tex]q= 79420 \ J[/tex]

79, 420 Joules of heat must be added.

Answer:

Metals , silver and copper which allows to pass the electricity through it is called good conductor of electricity .

hope it is helpful to you ☺️

Answer:

(6 mol)·(-393.5 kJ/mol) + (6 mol)·(-285.83 kJ/mol) - (1 mol)·(-1,273.02 kJ/mol) + (6 mol)·(0 kJ/mol)

Explanation:

Question; From the given options, the chemical reaction in the question is presented as follows;

C₆H₁₂O₆(s) + 6O₂(g) → 6CO₂(g) + 6H₂O(l), given that we have;

[tex]\Delta \text H _f^{\circ}[/tex] for C₆H₁₂O₆ = -1,273.02 kJ/mol

[tex]\Delta \text H _f^{\circ}[/tex] for O₂(g) = 0 kJ/mol

[tex]\Delta \text H _f^{\circ}[/tex] for CO₂(g) = -393.5 kJ/mol

[tex]\Delta \text H _f^{\circ}[/tex] for H₂O(l) = -285.83 kJ/mol

The heat or enthalpy of a reaction,  is given as follows;

[tex]\Delta\text H_{rxn}^{\circ} = \sum \text n \cdot \Delta \text H _f^{\circ}(\text {products}) - \sum \text m \cdot \Delta \text H _f^{\circ}(\text {reactants} \text)[/tex]

Therefore, the equation which should be used to calculate [tex]\Delta\text H_{rxn}^{\circ}[/tex], is given as follows;

[tex]\sum \text n \cdot \Delta \text H _f^{\circ}(\text {products})[/tex] = (6 mol)·(-393.5 kJ/mol) + (6 mol)·(-285.83 kJ/mol)

[tex]\sum \text m \cdot \Delta \text H _f^{\circ}(\text {reactants} \text)[/tex] = (1 mol)·(-1,273.02 kJ/mol) + (6 mol)·(0 kJ/mol)

Therefore;

[tex]\Delta\text H_{rxn}^{\circ}[/tex] = (6 mol)·(-393.5 kJ/mol) + (6 mol)·(-285.83 kJ/mol) - (1 mol)·(-1,273.02 kJ/mol) + (6 mol)·(0 kJ/mol)

Answer:

no lo se yo hablo en español no en ingles

Answer: The vapor pressure of ethanol at [tex]26.3^{o}C[/tex] is 238.3 torr.

Explanation:

Given: [tex]\Delta H_{vap}[/tex] = 38.6 kJ/mol

[tex]T_{1} = 26.3^{o}C = (26.3 + 273) K = 299.3 K[/tex]

[tex]T_{2} = 78.4^{o}C = (78.4 + 273) K = 351.4 K[/tex]

Formula used to calculate the vapor pressure of ethanol is as follows.

[tex]ln\frac{P_{2}}{P_{1}} = \frac{\Delta H_{vap}}{R} [\frac{1}{T_{1}} - \frac{1}{T_{2}}]\\[/tex]

Substitute the values into above formula as follows.

[tex]ln\frac{P_{2}}{P_{1}} = \frac{\Delta H_{vap}}{R} [\frac{1}{T_{1}} - \frac{1}{T_{2}}]\\ \\ln \frac{760 torr}{P_{1}} = \frac{38600 J}{8.314 J/mol K}[\frac{1}{299.3} - \frac{1}{351.4}]\\\frac{760}{P_{1}} = 3.18\\P_{1} = 238.3 torr[/tex]

Thus, we can conclude that the vapor pressure of ethanol at [tex]26.3^{o}C[/tex] is 238.3 torr.

Answer:

There is 7642 grams of CO2 released

Explanation:

Step 1: Data given

carbon dioxide = CO2

Molar mass of carbon dioxide = 44.01 g/mol

Mass of ethanol = 4 kg = 4000 grams

Molar mass of ethanol = 46.07 g/mol

Step 2: The reaction

Combustion of ethanol means there is oxygen (O2) added. The products are CO2 and H2O.

C2H5OH + 3O2 → 2CO2 + 3H2O

Step 3: Calculate number of moles of ethanol

Moles ethanol = mass ethanol / molar mass ethanol

Moles ethanol = 4000 grams / 46.07 g/mol

Moles ethanol = 86.82 moles

Step 4: Calculate number of moles CO2

For 1 mol ethanol we need 3 moles to produce 2 moles CO2 and 3 moles H2O

For 86.82 moles of ethanol we'll have 2*86.82 = 173.64 moles CO2

Step 5: Calculate mass of CO2

Mass CO2 = moles CO2 * molar mass CO2

Mass CO2 = 173.64 moles * 44.01 g/mol

Mass CO2 = 7642 grams

There is 7642 grams of CO2 released