help with this question
5. Which of the following elements will have a charge of 4+ or 4- as an ion?
Answer:
The answer would either be Carbon or Silicon.
Explanation:
If you have 2.0 moles of sodium chloride (NaCl), what is its mass in grams?
Answer:
117g
Explanation:
Given parameters:
Number of moles = 2moles
Unknown:
Mass of NaCl = ?
Solution:
To solve the problem, we need to use the expression below;
Mass of NaCl = number of moles x molar mass
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
So;
Insert the parameters and solve;
Mass of NaCl = 2 x 58.5 = 117g
How many moles are in 2.43 x 1024 particles of Carbon Monoxide (CO)?
a.0.25 moles
b.4.04 moles
c.1.46 moles
d.2.53 moles
Question:
In a laboratory demonstration, a balloon filled with methane and oxygen was exposed to a
flame. The result was a brief, large flame. The students were asked to formulate an equation for
the reaction. One answer is below.
CH, + 0 = CO,
This equation is incorrect.
A. Explain how and why it is incorrect
B. What would the correct equation be, and how do you know that?
Answer:
The laboratory demonstration consists of the following;
The compounds present in the combustion reaction = Methane, CH₄ and Oxygen, O₂
The chemical equation for the combustion reaction is given as follows;
CH₄ + 2O₂ → CO₂ + 2H₂O
Therefore;
A. The equation given as CH₄ + O → CO₂ is not correct because;
1) Oxygen gas exist as diatomic molecules, O₂, and given that the experiment involves the mixture of gases, the oxygen gas present which can exist as a separate compound, should be represented as O₂
2) The number of oxygen molecules in the reaction is two rather than one
3) The product also includes two molecules of water (vapor) H₂O
B. The correct equation for the reaction should be given as follows;
CH₄ + 2O₂ → CO₂ + 2H₂O
B i) The constituents of the equation is obtained by the knowledge of the fact that the combustion reaction of an organic substance such as methane in the presence of oxygen yields, carbon dioxide and water (vapor)
The equation showing the relative amounts the reacting compounds is by balancing the basic equation of the combustion of methane in the presence of oxygen
Explanation:
calculate the energy required to vaporize a chunk of ice at -25°C with the mass of 12.5kg
Ethanol (C2H5OH) melts at –114 °C and boils at 78 °C. The enthalpy of fusion of ethanol is 5.02 kJ/mol, and its enthalpy of vaporization is 38.56 kJ/mol. The specific heats of solid and liquid ethanol are 0.97 J/g-K and 2.3 J/g-K, respectively. The average specific heat of gaseous ethanol is about 1.80 J/g-K. a. How much heat is required to convert 35.0 g of ethanol at 27 °C to the vapor phase at 120 °C? b. How much heat is required to convert the same amount of ethanol at –120 °C to the vapor phase at 120 °C?
Answer:
First question
[tex]Q = 36826 \ J[/tex]
Second question
[tex]Q = 52299.7 \ J[/tex]
Explanation:
From the question we are told that
The melting point of Ethanol is [tex]T_m = -114 ^oC[/tex]
The boiling point of Ethanol is [tex]T_b = 78^ oC[/tex]
The enthalpy of fusion of Ethanol is [tex]F = 5.02 \ kJ / mol = 5.02 *10^{3}\ kJ / mol[/tex]
The enthalpy of vaporization of Ethanol is [tex]L = 38.56 \ kJ / mol = 38.56 *10^{3} \ J / mol[/tex]
The specific heat of solid Ethanol is [tex]c_e = 0.97 \ J/ g \cdot K[/tex]
The specific heat of liquid Ethanol is [tex]c_l = 2.3 \ J / g \cdot K[/tex]
The mass of the Ethanol given is [tex]m = 35.0 \ g[/tex]
Considering the first question
The initial temperature is [tex]T_i = 27^oC[/tex]
The final temperature is [tex]T_f = 120^oC[/tex]
Generally the heat required too raise the Ethanol to its boiling point is mathematically represented as
[tex]Q_1 = m * c_l * (T_b - T_i)[/tex]
=> [tex]Q_1 = 35.0 * 2.3 * ( 78 - 27)[/tex]
=> [tex]Q_1 =4106 \ J[/tex]
Genially the number of moles of Ethanol given is mathematically represented as
[tex]n = \frac{m}{Z}[/tex]
Here Z is the molar mass of Ethanol with value [tex]Z = 46 g/mol[/tex]
So
[tex]n = \frac{35}{46 }[/tex]
=> [tex]n = 0.7609 \ mol[/tex]
Generally the heat of vaporization of the Ethanol is mathematically represented as
[tex]Q_2 = n * L[/tex]
=> [tex]Q_2 =0.7809 * 38.56 * 10^{3}[/tex]
=> [tex]Q_2 =29339 \ J[/tex]
Generally the heat required too raise the Ethanol from its boiling point to [tex]T_f[/tex] is mathematically represented as
[tex]Q_3 = m * c_l * (T_f - T_b)[/tex]
=> [tex]Q_3 = 35 * 2.3 * (120 - 78 )[/tex]
=> [tex]Q_3 = 3381 \ J[/tex]
Generally the total heat required is
[tex]Q = Q_1 + Q_2 + Q_3[/tex]
=> [tex]Q = 4106 + 29339 + 3381[/tex]
=> [tex]Q = 36826 \ J[/tex]
Considering the second question
The initial temperature is [tex]T_i = -120^oC[/tex]
The final temperature is [tex]T_f = 120^oC[/tex]
Generally the heat required too raise the Ethanol to its melting point is mathematically represented as
[tex]Q_1 = m * c_e * (T_m - T_i)[/tex]
=> [tex]Q_1 = 35.0 * 0.97 * ( -114 - (- 120) )[/tex]
=> [tex]Q_1 = 203.7 \ J[/tex]
Generally the heat of fusion of the Ethanol is mathematically represented as
[tex]Q_2 = n * F[/tex]
=> [tex]Q_2 =0.7809 * 5.02 *10^{3}[/tex]
=> [tex]Q_2 =3920 \ J[/tex]
Generally the heat required too raise the Ethanol to its boiling point is mathematically represented as
[tex]Q_3 = m * c_l * (T_b - T_m)[/tex]
=> [tex]Q_3 = 35.0 * 2.3 * ( 78 - (- 114) )[/tex]
=> [tex]Q_3 =15456 \ J[/tex]
Generally the heat of vaporization of the Ethanol is mathematically represented as
[tex]Q_4 = n * L[/tex]
=> [tex]Q_4 =0.7809 * 38.56 * 10^{3}[/tex]
=> [tex]Q_4 =29339 \ J[/tex]
Generally the heat required too raise the Ethanol from its boiling point to [tex]T_f[/tex] is mathematically represented as
[tex]Q_5 = m * c_l * (T_f - T_b)[/tex]
=> [tex]Q_5 = 35 * 2.3 * (120 - 78 )[/tex]
=> [tex]Q_5 = 3381 \ J[/tex]
Generally the total heat required is
[tex]Q = Q_1 + Q_2 + Q_3+Q_4 + Q_5[/tex]
=> [tex]Q = 203.7 + 3920 + 15456 +29339+3381[/tex]
=> [tex]Q = 52299.7 \ J[/tex]
Can farmers simply plant more acres of crops to feed a growing population?
Answer:
I believe they can if it's a small town/village
Explanation:
How can magnetic force be exerted on objects?
1)Over a distance and anytime an object is in a magnet's field of influence.
2)Only through objects.
3)Only by touching an object.
what are the three types of nuclear decay or reactions?
Answer:
alpha decay, beta decay, gamma decay
what is an extensive prperty of matter
Answer:
Volume
Mass
Size
Weight
Length
Explanation:
Extensive properties do depend on the amount of matter that is present. An extensive property is considered additive for subsystems. Examples of extensive properties include:
Volume
Mass
Size
Weight
Length
How many grams are in 7.5 moles of C6H12?
Group of answer choices
0.09g
630g
11.2
84g
Answer:
630gC₆H₁₂
Explanation:
How many grams are in 7.5 moles of C₆H₁₂?
C₆:12.011×6=72.066
H₁₂:1.008×12=12.096
72.066+12.096=84.162
84.162g/mol C₆H₁₂
7.5 molC₆H₁₂ ×84.162g/molC₆H₁₂= 631.215gC₆H₁₂
Are the atoms really "sharing" electrons
explain how to separate sugar from supersaturated sugar solution
guys pls help
A “supersaturated” solution contains more dissolved material. supersaturated solutions lies in the temperature of the water. more sugar will dissolve in hot water than in cold. Meaning that by separating the 2, only the supersaturated sugar would dissolve leaving the regular sugar untouched.
Someone please help will mark as brainliest
Answer:
a1
The main difference between SPECT and PET scans is the type of radiotracers used. While SPECT scans measure gamma rays, the decay of the radiotracers used with PET scans produce small particles called positrons. A positron is a particle with roughly the same mass as an electron but oppositely charged.
Explanation:
a2
While imaging tests such as X-rays can show what the structures inside your body look like, a SPECT scan produces images that show how your organs work. For instance, a SPECT scan can show how blood flows to your heart or what areas of your brain are more active or less active.
a3
PET and SPECT have been extensively evaluated as diagnostic procedures for dementia. Substantial progress has been made in developing radioligands that bind to amyloid deposits in the brain, which should provide new opportunities for early diagnosis and treatment monitoring in Alzheimer's disease
a4
What are the disadvantages of spect as compared to pet?
However, SPECT has issues, including long scan times and low-resolution images prone to artifacts and attenuation. Some artifacts can easily be misidentified as perfusion defects. SPECT also does not provide a quantifiable estimate of the blood flow, whereas PET does, experts say.
which forces are contact forces? which r non contact forces/
magnetic force,friction,air resistance,gravitational force eletrostatic force and upupthrust
the force that holds paticles together in the atomic nuecleaus?
Explanation:
i believe you meant particles*
A sound wave moves from a solid material into a liquid. What would happen to the frequency of the sound?
What happens when a virus becomes latent?
Answer:
the full viral genome is retained in the host cell, but its expression is dramatically restricted, such that few viral antigens and no viral particles are produced.
Explanation:
Aqueous solutions of sodium carbonate and magnesium chlorate are mixed
Explanation:
You're mixing magnesium nitrate, Mg(NO3)2 , and sodium carbonate, Na2CO3 , two soluble ionic compounds that dissociate completely in aqueous solution to form cations and anions.
Explain why the electron configuration of 2-3-1 represents an atom in an excited state?
Answer:
See explanation
Explanation:
If we look at the electron configuration closely, we will discover that the element must have had a ground state electron configuration of 2,4.
This is because, the innermost shell usually holds two electrons while the outer shells hold eight electrons each. The four electrons must be accommodated in the second shell in the ground state configuration of the compound.
However, when the atom is excited, one electron from this shell may move to the third shell to give the excited state configuration 2-3-1 as shown in the question.
Which will diffuse the most? The particles with the
A. Least potential energy.
B. Most potential energy.
C. Least kinetic energy.
D. Most kinetic energy.
Answer:
B. Most potential energy
Explanation:
brainest plz
Which of the following is an intensive property?
Mass
Magnetism
Shape
Volume
Answer:
I believe its A. Mass
Explanation:
An intensive property is a property of matter that depends only on the type of matter in a sample and not on the amount. For example, the electrical conductivity of a pure substance is a property that depends only on the type of substance. Silver, gold, and copper are excellent conductors of electricity, while glass and plastic are poor conductors.. Other intensive properties include color, temperature, density, and solubility.
Answer:
B. Magnetism
Explanation:
Hope this helps! :))
Sorry for late answer
a flask of 0.30 L was weighted after it had been evacuated.It was then filled with a gas of unknown molecular mass at 760 mm of Hg and temperature of 300 K. The increase in mass of flask was found to be 0.997 g. Determine the molecular mass
The molecular mass : 81.72 g/mol
Further explanationIn general, the gas equation can be written
[tex]\large {\boxed {\bold {PV = nRT}}}[/tex]
where
P = pressure, atm , N/m²
V = volume, liter
n = number of moles
R = gas constant = 0.082 l.atm / mol K (P= atm, v= liter),or 8,314 J/mol K (P=Pa or N/m2, v= m³)
T = temperature, Kelvin
P = 760 mmHg=1 atm
T = 300 K
V = 0.3 L
Number of moles :
[tex]\tt n=\dfrac{PV}{RT}\\\\n=\dfrac{1\times 0.3}{0.082\times 300}\\\\n=0.0122[/tex]
The molecular mass (MW) :
[tex]\tt MW=\dfrac{mass}{n}\\\\MW=\dfrac{0.997~g}{0.0122}\\\\MW=81.72~g/mol[/tex]
how to find the electron in an atom/element
Answer:
to find the number of electrons an element has locate it on the periodic table of elements find the atomic number and note the number of protons because they are naturally electrically neutral
Answer:
M-A=N
Explanation:
M-A=N
Here is an example.
The equation above means that the atomic number (A) subtracted from the average atomic mass (M) equals the combined amount of neutrons and protons. Since we know that 35 17Cl is Chlorine (this is because Chlorine (Cl) is the 17th number on the periodic table and has the average atomic mass of 35), we can insert our data into the equation and end up with the following:
35-17=18.
From here, we can tell that we have a mix of neutrons and protons, with the total being 18. Since the atomic number is 17, we can reasonably assume that there are 17 protons and 1 neutron.
But we still need to find the number of electrons. Fortunately, the number of electrons is always equivilant to the number of protons and the atomic mass, so we know that the number of electrons is 17.
So, we have;
17 Protons
1 Neutron
17 Electrons
PLEASEEE answer correctly! I will give u 10pts and brainleist if u get it right please:) (SCIENCE)
Answer:
The answer is 2
Explanation:
when viewed from earth number 2 would be a waning gibbous
How to we measure energy?
Answer:
The official measurement unit for energy is the Joule (J). Among the most common units measuring energy mention should be made of the kilowatt/hour (kWh), used especially for electric energy (in fact it is used to calculate electricity bills).
Which has the larger atomic radius Ga Or B
Answer:
Ga-135 is the largest atomic radius because B atomic radius is 85
What is a mixture of sugar and water?
a solution
molecule
a compound
a precipitate
Explanation:
I think its a solution just me tell me in comments if right
Answer:
A solution
Explanation:
Sugar is soluble in water and would dissolve into the water to form a solution.
Someone please help will mark as brainliest
1. solute is the substance that is being dissolve,while solvent is dissolving medium
2.saturated is solution that contain maximum amount of solut that capable of being dissolve and supersaturated is solution that contain less amount or medium of solut that capable being dissolve : example vinger
3. is a number placed in front of a chemical symbol or formula. It shows how many atoms or molecules of the substance are involved in the reaction. For example, two molecules of hydrogen would be written as 2 H2, and two molecules of water would be written 2 H2O . yes it's can be change only in caseWhen you balance an equation you can only change the coefficients