Answer: C
Explanation:
In endothermic reactions, enthalpy is positive, and in exothermic reactions, enthalpy is negative, So, if enthalpy is positive, then it is an endothermic reaction, and hence is required for the reaction to occur.
Question 12
How many moles of aluminum phosphate are produced when 6.8 moles of aluminum nitrate
reacts?
A dodecahedron must have 12 faces
Of these 12 faces, two must be the top & base.
So there shall be 10 faces on the lateral surface.
Hence there shall be 5 on one half & 5 on the other half.
To have 5 faces on the base of a regular polygon, the base must have 5 sides.
So it must be a regular pentagon.
The faces of a regular dodecahedron are regular pentagons.
Option C) is the right answer.
An image is attached for your reference.
Explanation:
A 700 mL sample of nitrogen is heated from 37 °C to 77 °C at constant pressure. What is the final volume? a. 790 L b. 790 ml c. 970 ml d. 970 L
The final volume of the nitrogen sample would be 790 mL
Charle's LawAccording to Charles, at constant pressure, the volume of a gas is directly proportional to its temperature.
Mathematically: v1/t1 = v2/t2, where v1 and v2 = initial and final volume, and t1 and t2 = initial and final temperature.
In this case, t1 = 37 °C or 310 K, t2 = 77 °C or 350 K, v1 = 700 mL
Thus: v2 = v1 x t2/t1 = 700 x 350/310 = 790 mL
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& Sodium chloride, sugar, starch, and sand are added to water separately in different beakers and the mixtures are stirred well. A suspension will be formed in which case? Give any two reasons for your choice.
Answer:
sugar I like it I think iyrx
Edge Modeling Nuclear Changes
Summarize nuclear changes.
a) Use your completed table and models to write a summary that addresses the following questions:
1. How does energy change in these reactions? Is energy needed to start the reactions or is energy given off in the reactions? For each type of reaction, approximately how much energy is released?
2. How do these energy changes compare in scale to other types of reactions, such as chemical reactions?
Part 1
During nuclear reactions, energy is released.To calculate energy changes, use the attached process.Part 2
In nuclear reactions, much more energy is released than in other types of reactions, such as chemical reactions.
lodine-131 is a radioactive isotope with a half-life of 8 days. How many grams of a 50 g sample will be left after 48 days?
Answer:
0.805 or 0.781 depending on the method used.
Explanation:
Data provided
half life ie t1/2= 8days.
No= 50g
t=48days
Nt=?
Method 1
Formula: Nt= No(1/2)^n
where n= number of half lives.
= t/t1/2 = 48/8
=6.
thus Nt= 50(1/2)^6= 0.781
Method 2
Formula: Nt= Noe^-(lambda)t
where lambda= decay constant
= ln2/ t1/2= ln2/ 8 = 0.086.
thus Nt= 50e^-(0.086×48)= 0.805.
The empirical formula for a compound is C2H4NO. If its molar mass is 232.2 g/mol, what is the molecular formula of the compound?
Empirical formula mass
C2H4NO2(12)+4(1)+14+1630+24+458g/molMolar mass=232.2g/mol
Find n
Molar mass/Empirical formula mass232.2/584Molecular formula
n×Empirical formula4(C2H4NO)C8H16(NO)_4Find the empirical formula mass
2(12u)+4(1u)+14u+16u58u or 58g/molFind n
Molar mass/Empirical mass232.2/584.05Round to nearest whole
n=4Molecular formula
4(C2H4NO)C8H16N4O4convert from grams to moles for 36g CO2
Answer:
0.82 moles CO₂
Explanation:
To convert from grams to moles, you need to find the molar mass of CO₂. This conversion is a ratio stating the amount of grams CO₂ per 1 mole. The molar mass is calculated using the molar mass of each element (in CO₂) from the periodic table.
Molar Mass (Carbon): 12.011 g/mol
Molar Mass (Oxygen): 15.998 g/mol
Molar Mass (CO₂): 12.011 g/mol + 2(15.998 g/mol)
Molar Mass (CO₂): 44.007 g/mol
36 grams CO₂ 1 mole
---------------------- x -------------------------- = 0.82 moles CO₂
44.007 grams
What is the molecularity of the elementary step X + X + Y → Z?
The molecularity of the elementary step X + X + Y → Z is 3.
What is Molecularity ?Molecularity in chemistry is defined as the total number of molecules that react in an elementary reaction .
In the given question the elementary reaction given is
X + X + Y → Z?
or 2X +Y --> Z
X molecule is 2 and Y molecule is 1 so the molecularity is 2+1 = 3
The molecularity of the elementary step X + X + Y → Z is 3.
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A certain gas has a molar mass of 28.0 g mol. Calculate the mass of this gas that would fit into a 3.00 litre container at 182 kPa and 47.2 °C?
Answer:
5.74 gm
Explanation:
First, use the ideal gas law PV = n RT
to find the number of moles, then multiply by 28 g/ mole
PV = n RT T must be in Kelvin R = 8.314463 L kPa/(K - Mol)
( make sure you use the R with the correct units!!)
182 kPa * 3 L = n (8.314463 ) ( 273.15+47.2)
solve for n = .205 moles
.205 mole * 28 g/mole = 5.74 gm
The mass of the gas can be calculated using ideal gas law. The mass of the gas is approximately 1.37 g.
What is ideal gas law ?According to ideal gas law, the pressure , volume temperature and number of a moles of a gas is related as :
PV = nRT
To calculate the mass of a gas that would fit into a container at a given temperature, pressure, and volume, we can use the ideal gas law equation:
PV = nRT
where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in Kelvin.
We can rearrange this equation to solve for the number of moles:
n = PV/RT
Once we know the number of moles, we can use the molar mass of the gas to calculate the mass of the gas:
mass = n x molar mass
where molar mass is given as 28.0 g/mol.
Substituting the given values, we get:
n = (182 kPa) x (3.00 L) / [(8.31 J/mol-K) x (47.2°C + 273.15)] = 0.0489 moles
mass = 0.0489 moles x 28.0 g/mol = 1.37 g
Therefore, the mass of the gas that would fit into a 3.00 L container at 182 kPa and 47.2°C is approximately 1.37 g.
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Determine the number of valence electrons for sodium through the use of this table.
Na =
Answer:
Sodium has one valence electron. Valence electrons are electrons found in the outermost shell of an atom. The shell number representing the valence shell will differ depending on the atom in question. For sodium, which is in the 3rd row of the periodic table, the valence electrons will be found in the 3rd shell.
0.0010 M NaOH calculate the pH of this solution
See below~
[tex] [OH^{-}] = 0.001 \\ = 10^{-3} M \Longrightarrow pOH = 3 \\ pH + pOH = 14 \Longrightarrow pH = 14-3 = 11[/tex]
The pH of a 0.0010 M NaOH solution is approximately 11.
To calculate the pH of a solution, you need to determine the concentration of hydrogen ions ([H+]). In the case of a strong base like NaOH, the concentration of hydroxide ions ([OH-]) can be used to calculate the concentration of hydrogen ions.
Given that NaOH is a strong base, it dissociates completely in water to form Na+ and OH- ions. The concentration of hydroxide ions can be assumed to be the same as the concentration of NaOH.
In this case, the concentration of NaOH is given as 0.0010 M.
Since [OH-] = 0.0010 M, we can use the Kw (ionization constant of water) to calculate [H+].
Kw = [H+][OH-] = 1.0 x [tex]10^{-14}[/tex]
[H+] = Kw / [OH-]
[H+] = (1.0 x [tex]10^{-14}[/tex]) / (0.0010)
[H+] = 1.0 x [tex]10^{-11}[/tex]M
To calculate the pH, we use the formula: pH = -log[H+]
pH = -log(1.0 x [tex]10^{-11}[/tex])
pH ≈ 11
Therefore, the pH of a 0.0010 M NaOH solution is approximately 11.
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1) H₂(g)+Br₂(g)➝2HBr(g) has a heat of reaction of ___ kJ.
2)CH₄(g)+I₂(g)➝CH₃I(g)+HI(G) has a heat of reaction of ___kj.
3)N₂H₄(I)+O₂(g)➝N₂(g)+ 2 H₂O(g) has a heat of reaction of __kj.
see the attached file!!
On a cold day a person takes in a breath of 450.0 mL of air at 756 mmHg and -10.0C. Assuming that amount and pressure remain constant, what is the volume of the air when it warms to body temperature (37C) in the lungs?
that science I'm not good really at that
Which symbol represents a type of radiation that has the same mass as an
electron and a positive charge?
OA. e
OB. OY
O C. e
O D. He
Answer:
D.+1°e symbol represents a type of radiation that has the same mass as an electron and a positive charge.
How many protons,neutrons, and electrons does uranium 238 have
Explanation:
92 protons 92 electrons and 146 neutrons
Answer:
92 protons, 92 electrons, 146 neutrons
Explanation:
U-238 has 92 protons, 92 electrons, 146 neutrons.
The 238 is mass number talking about protons + neutrons. Uranium will always have 92 protons so the rest of the things are neutrons (146). Electrons will always equal protons if the element is neutral (no charge) and since no charge was given the numbers will match
differentiate between ideal and non - ideal solutions.
[tex] \\ [/tex]
ty! ~
Answer:
Ideal Solution: An ideal solution is a solution where interactions between molecules are identical between all the molecules in the solution. Non ideal Solution: A non ideal solution is a solution that has differences in the interactions between molecules of different components in the solution.
Explanation:
Answer:
Ideal solutions obey Raoult's law over entire range of concentrations. Nonideal solutions do not obey Raoult's law over the entire range of concentrations. 2. The vapour pressure of ideal solution always lies between vapour pressures of pure components.
What is the grams per liter concentration of a solution
composed of 8.210 g of potassium chloride, KCI,
dissolved in enough water to make 0.300 L of solution?
a. 0.0846 g/L
b. 16.4 g/L
c. 0.367 g/L
d. 27.4 g/L
Grams per liter in the solution give the density of the solution. The density of the solution is 27.4 g/L. Thus, option d is correct.
What is density?Density is the ratio of the mass in gms to the volume of the solution in liters.
Given,
Mass of potassium chloride = 8.210 gms
Volume of solution = 0.300 L
Density is calculated as:
ρ = mass ÷ volume
= 8.210 ÷ 0.300
= 27.36 g/L
Therefore, the density of the solution is 27.4 g/L.
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8. Which conditions in the atmosphere would cause smoke from a campfire on a beach to blow toward the ocean?
Answer:
warm air over the land and cool air over the ocean.
Which of the following best defines balanced forces?
A. Forces that act in opposite directions and cancel each other out
B. Unequal forces that do not cancel out and that cause a change in
motion
OC. The total force on an object after individual forces are added
together
D. Forces between two objects in physical contact
Answer:
Balanced forces are forces that act in opposite directions and cancel each other out
let me know if you have any other questions
Answer:
Discuss about Library Automation Life cycleExplanation:
How many moles are there in 42.2g of Cu₂SO4?
Answer:
0.264moles
Explanation:
number of moles= given mass/molar mass.
Molar mass of Cu2SO4= 63.5+32+4(16)=159.5
moles(n)=42.2/159.5= 0.264moles
) Calculating Heat from Thermochemical Equations
The thermochemical equation for the combustion of methane gas is:
Calculate much heat is released when 3.5 moles of methane gas undergo a combustion reaction.
A combustion reaction is a reaction that reacts in the presence of oxygen molecules. Methane will release -3115 kJ/mol of heat.
What is a combustion reaction?A combustion reaction includes the reaction between the chemical reactant and oxygen molecule to produce the product. The combustion reaction between methane and oxygen is given as:
CH₄(g) + 2O₂ (g) → CO₂(g) + 2H₂O (l), ΔH = -890 kJ/mol
The stoichiometry coefficient from the reaction gives 1 mole of methane releases -890 kJ/mol enthalpy.
So, 3.5 moles methane will release = 3.5 × -890 = -3115 kJ/mol
Therefore, -3115 kJ/mol of heat is released.
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How do I create an atom with a mass of 3 and a neutral charge?
Answer:
a lithium atom (Z=3, A=7 AMU) contains three protons (found from Z), three electrons (as the number of protons is equal to the number of electrons in an atom), and four neutrons (7 – 3 = 4).
Explanation:
Chris noticed a high-pressure system in the weather forecast for Monday
and Tuesday. Which type of weather conditions are most likely for those
two days?
clear and sunny
cold and stormy
cloudy and rainy
D. warm and stormy
Answer:
A. Clear and Sunny
Explanation:
The answer would be A. Clear and Sunny. A high pressure system occurs where the air mass above the Earth is denser than in surrounding areas, and therefore exerts a higher force or pressure. They usually happen with li9ght winds. Using process of elimination, it could not be D. Warm and Stormy, C. Cloudy and Rainy, or B. Cold and Stormy because all have wet climates.
Which two nuclides are isotopes of the same element
Answer:
1940K and 1939K Isotopes are two forms of the same element that have different numbers of neutrons in the nucleus. This means same symbol, and same atomic number (subscript), but different mass number (superscript).
What causes ocean water near the equator to be warmer than ocean water
farther north?
O A. The sun's rays strike the water more directly near the equator.
B. Because of Earth's rotation, gyres near the equator flow clockwise.
C. Deep-sea vents pump steam into the ocean's conveyor belt near
the equator.
D. The water is denser and saltier near the equator, so it holds more
heat.
Answer:
A. The sun's rays strike the water more directly near the equator.
Explanation:
I pass the test
3) A gas has a volume of 15.0 mL at a pressure of 1.05 atm. What is the volume of the gas at
a pressure of 0.450 atm?
Answer:
V⬇2=64.mL this is the answer and the 2 is supposed to be at the bottom which the arrow stands for so do not put the arrow with that
what is called a measurement and does involve a number and unit in chemistry?
Answer:
1.1: Taking Measurements. Chemists measure the properties of matter and express these measurements as quantities. A quantity is an amount of something and consists of a number and a unit. The number tells us how many (or how much), and the unit tells us what the scale of measurement is.
!!
If you add more ammonia, NH3 (ag), to the equilibrium mixture described by the equation here,
what will happen?
2+
2+
Cu(H₂0)6(aq) + 6NH3 (aq) = Cu(NH3) 6 (aq) + 6H₂0(aq)
O It will shift to the right
O It will shift to the left
O It will shift right and left
O It will remain still
Next ▸
If more ammonia is added to the reaction at equilibrium, the equilibrium will shift to the right.
Le Cha-teliar's principleThe principle states that reactions at equilibrium will always adjust to neutralize any effect due to constraints.
Thus, ammonia being a reactant in the reaction will make the equilibrium shift to the right because the reaction will adjust to annul the effects of increasing the concentration of ammonia in the reaction.
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Which of the following is not one of the four things that all organisms need to survive?
A. water
B. air
C. a source of energy
D. the ability to move
Answer:
b
Explanation:
this is because all organisims need water, c is out of the question because no energy is needed, d is out because it is needed for fighting against predators
Complete the sentence using ide, ate or Ic. To determine the name of an anion, you take the name of its element and replace the end with
To determine the name of an anion, you take the name of its element and replace the end with "ide".
What is an anion?An anion in chemistry is a negatively charged ion.
Anions are usually formed when a non-metallic atom gains electron(s).
An anion is usually named by taking the elemental name, removing the ending, and adding “ide.
Examples of anions are as follows:
fluoride (F-)Chloride (Cl-)Iodide (I-)Learn more about anions at: https://brainly.com/question/15578817
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