Câu 15: Nguyên tử X nặng gấp 2 lần nguyên tử cacbon. Nguyên tử X đó có nguyên tử khối và

kí hiệu hóa học là

A. 24_Mg. B. 16_O C. 56_Fe D. 32_S

Taking into account the definition of dilution,  the new concentration of the solution is 0.2567 M.

First of all, you have to know that   dilution is the reduction in concentration of a chemical in a solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.

In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volumeof the solution increases.

A dilution is mathematically expressed as:

Ci×Vi = Cf×Vf

where

In this case, you know:

Replacing in the definition of dilution:

0.385 M× 0.600 L= Cf× 0.900 L

Solving:

Cf= (0.385 M× 0.600 L)÷ 0.900 L

Cf= 0.2567 M

In summary, the new concentration of the solution is 0.2567 M.

Learn more about dilution:

Answer:

Explanation:

CH4 + 2O2 ==> CO2 + 2H2O

mols CH4 = grams/molar mass

Using the coefficients in the balanced equation, convert mols CH4 to mols CO2.

Now convert mols CO2 to grams. g = mols x molar mass.

Answer:

Seven methods were used to assess water quality in the river system. These methods included single-factor assessment, water quality grading, comprehensive pollution index, the Nemerow pollution index, principle component analysis, fuzzy comprehensive evaluation, and comprehensive water quality identification index.

The heat released in the combustion of lactic acid is absorbed by the

calorimeter and in the decomposition of the lactic acid.

ΔH°f of lactic acid is approximately -716.2 kJ

Reasons:

Known parameters are;

Mass of the lactic acid = 3.93 grams

Heat  capacity of the bomb calorimeter = 10.80 kJ·K⁻¹

Change in temperature of the calorimeter, ΔT = 5.34 K

ΔHrxn = ΔErxn

ΔH°f of H₂O(l) = -285.8 kJ·mol⁻¹

ΔH°f of CO₂(g) = -393.5 kJ·mol⁻¹

The chemical equation for the reaction is presented as follows;

The heat of the reaction = 10.80 kJ·K⁻¹ × 5.34 K = 57.672 kJ

Molar mass of C₃H₆O₃ = 90.07 g/mol

Number of moles of C₃H₆O₃ = [tex]\dfrac{3.93 \, g}{90.07 \, g/mol}[/tex] = 0.043633 moles

Number of moles of CO₂ produced = 3 × 0.043633 moles = 0.130899 moles

Heat produced = 0.130899 mole × -285.8 kJ·mol⁻¹ = -37.4109342 kJ

Moles of H₂O produced = 0.130899 moles

Heat produced = 0.130899 mole × -393.5 ≈ -51.51 kJ

Therefore, we have;

Heat absorbed by the lactic acid = ΔH°f of H₂O + ΔH°f of CO₂ + Heat absorbed by the calorimeter

Which gives;

Heat absorbed by lactic acid  = -37.4109342 kJ - 51.51 kJ + 57.672 kJ ≈ -31.249 kJ

The heat absorbed by the lactic acid ≈ -31.249 kJ

ΔH°f of C₃H₆O₃ ≈ -716.2 kJ

Heat of formation of lactic acid ≈ -716.2 kJ.

Learn more here:

https://brainly.com/question/13185938

Answer:

here is no question (e).............

We want to find the concentration of the resulting solution of mixing 35mL of a given solution and 0.225 L of water.

We will find that the concentration is 13.5%.

First, we need to write both of these in the same units.

We know that:

1000 mL = 1L

Then:

35 mL = 0.035 L

So when we mix the solution and the water we end with a total volume of:

V = 0.035L + 0.225L = 0.260L

The concentration of solution will be equal to the quotient between the volume of solution we used (0.035 L) and the total volume of the mixture (0.260L)

We will get:

Concentration = (0.035L)/(0.260L) = 0.135

Now to write it as a percentage, we only need to multiply this by 100%.

0.135*100% = 13.5%

This means that the mixture has a concentration of the 13.5%.

If you want to learn more, you can read:

https://brainly.com/question/202460

Answer:

Explanation:

Most of this ancient space rubble can be found orbiting the Sun between Mars and Jupiter within the main asteroid belt. Asteroids range in size from Vesta – the largest at about 329 miles (530 kilometers) in diameter – to bodies that are less than 33 feet (10 meters) across.

Answer: yes

Explanation:

Answer:

Explanation:

Condensation is a process in which the evaporated liquid substance such as water vapor gets turned back to its liquid form water.

As per the details given, 48.6 g are present in 0.885 moles of manganese. The correct option is A.

To determine the gram contained in a given number of moles, use the element's molar mass. Manganese (Mn) has a molar mass of roughly 54.94 g/mol.

To calculate the grammes in 0.885 moles of manganese, use the following formula:

moles of Mn × molar mass of Mn = mass of Mn in grams

On calculating it:

0.885 moles × 54.94 g/mol = 48.60 g

Therefore, the mass of manganese present in 0.885 moles of manganese is 48.60 grams.

Thus, the correct answer is A. 48.6g.

For more details regarding molar mass, visit:

https://brainly.com/question/31545539

#SPJ6

These colligative properties include reduced vapor pressure, increased boiling point, decreased freezing point, and increased osmotic pressure.

To learn more about : Osmotic pressure

Ref : https://brainly.com/question/14208018

#SPJ2

so 2.46 X 10^28 contains (2.46 X 10^28)/(6.02 X 10^23) =

(2.46 X 10 X 10^27)/ (6.02 x(10^23) = (24.6/6.02) X 10^ (27-23)=

4.09 X 10^4 = 40,900

Answer:

4.09 X 10^4 = 40,900 moles

Explanation:

How many moles of Magnesium(Mg) are

in 2.46 x 10^28 atoms of Magnesium?

PLEASE LEARN THIS FUNDAMENTAL RULE OF CHEMISTRY...1 MOLE OF ANYTHING CONTAINS AVOGADROS NUMBER OF PARTICLES}

6.02 X 10^23.09

so 2.46 X 10^28 contains in moles(2.46 X 10^28)/(6.02 X 10^23) =

(2.46 X 10 X 10^27)/ (6.02 x(10^23) = (24.6/6.02) X 10^ (27-23)=

4.09 X 10^4 = 40,900 moles

Answer:

They want to know how long it has been since it last erupted.

Explanation:

Scientists study a volcano's history to try to predict when it will next erupt.  They also want to know the time span between its previous eruptions

Answer:

Answer: 1247.5 grams

Explanation:

explanation on image .

Answer:

Chemistry is sometimes called “the central science,” because it bridges physics with other natural sciences, such as geology and biology. Chemistry is the study of matter and its properties.

Explanation:

~found it~

Answer:

Refer to the attachment

Answer:

I don't know the answer sorry man

Answer:

2Cu + S ~~~> Cu2S Copper (C) reacts with sulfur (S) to form copper sulfide as shown in the equation. A scientist adds 12.7 grams of Cu to 3.2 grams of S to start the reaction.

Explanation:

Explanation:

a brittle, High melting solid : option B (MgCl2).

1) H2S

2) H2O

3) I2

weakest to strongest.

hope this helps you.

Answer:

c

Explanation:

c .

answer

your

this

questions

Answer:

C) 2CO + O₂ →   2CO₂

Explanation:

The equation C is correct.

2CO + O₂ →   2CO₂

This equation have four oxygen atom and two carbon atoms on both side of equation. So it is correctly balanced.

All others are incorrect:

A) CO + O₂ →   CO₂

this is incorrect because there are three oxygen atoms on left while two atoms on right.

B) CO + 2O₂ →   2CO₂

this is incorrect because there are five oxygen atoms on left while four atoms on right.

D)  2CO + 2O₂ →   2CO₂

this is incorrect because there are six oxygen atoms on left while four atoms on right.

In the pond, the percentage of fish left after ten days is 4%.

Given that;

N(t) = Noe^-kt

Where;

N(t) = percentage of fish at time t

No = Initial percentage of fish

k = rate constant

t = time taken

Given that we had 100% fish population at the beginning, we can see that this reaction is first order.

The rate constant is obtained from;

When t = 5

19 = 100e^-5k

19/100 =e^-5k

0.19 = e^-5k

ln 0.19 = -5k

k = ln (0.19)/-5

k = 0.33

In ten days;

N(10) = 100e^-0.33(10)

N(10) = 4%

Learn more: https://brainly.com/question/5624100

Answer:

The answer is 4 2 He. I know this because alpha decay occurs when an unstable nucleus emits an alpha particle which is identical to a helium-4 nucleus.

Answer:

I believe that would be methane! I hope this helps you!

Answer:

methane

Explanation:

The largest component of natural gas is methane, a compound with one carbon atom and four hydrogen atoms (CH4). Natural gas also contains smaller amounts of natural gas liquids (NGL, which are also hydrocarbon gas liquids), and nonhydrocarbon gases, such as carbon dioxide and water vapor.The main component in natural gas is methane. It also has ethane, propane, butane, hydrocarbons.

Taking into account the definition of density and scientific notation, the density of olive oil is 0.000911 [tex]\frac{kg}{mL}[/tex] or 9.11×10⁻⁴[tex]\frac{kg}{mL}[/tex]

Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space.

In other words, density is a quantity that allows us to measure the amount of mass in a certain volume of a substance.  That is, density is the relationship between the weight (mass) of a substance and the volume it occupies.

The expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:

[tex]density=\frac{mass}{volume}[/tex]

In this case, you know that:

Replacing in the definition of density:

[tex]density=\frac{0.216 kg}{237 mL}[/tex]

Solving:

density= 0.000911 [tex]\frac{kg}{mL}[/tex]

On the other side, scientific notation is a quick way to represent a number using powers of base 10.  

The numbers are written as a product:

a×10ⁿ

where:

In this case, the density expressed in scientific notation is: 9.11×10⁻⁴[tex]\frac{kg}{mL}[/tex]

In summary, the density of olive oil is 0.000911 [tex]\frac{kg}{mL}[/tex] or 9.11×10⁻⁴[tex]\frac{kg}{mL}[/tex]

Learn more

Answer:

Average kinetic energy of gases, which is derived from the RMS (root mean square speed) and KE equation, can be solved as:

It appears that the average KE of gases is dependent on the temperature which means that all gases will have the same KE as long the temperature is the same

the answer is is is is is is is is is is is is is is

Answer:

the the that keeps the water cycle going is heat