A negative enthalpy (ΔH)for a molecule means energy was released when the molecule went through a phase change.
What is change in enthalpy (ΔH)?The enthalpy change of a reaction is the amount of heat absorbed or released as the reaction takes place.
Also, the amount of energy required to change the phase of a material is known as the enthalpy,
A negative enthalpy entails the amount of energy released during an exothermic reaction.
Thus, a negative enthalpy (ΔH)for a molecule means energy was released when the molecule went through a phase change.
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Atoms are spherical in shape. Therefore, the Pt atoms in the cube cannot fill all the available space. If only 74.0 percent of the space inside the cube is taken up by Pt atoms, calculate the radius in picometers of a Pt atom. The mass of a single Pt atom is 3.240 × 10−22 g. [The volume of a sphere of radius r is (4/3) πr3. The volume of a cube is l3, where l is the length of a side. Avogadro's number is 6.022 × 1023.]
Answer:
Answer:
A)6.6×10^22atoms of Pt in the cube
B)1.4×10^-8m
Explanation:
(a) Calculate the number of Pt atoms in the cube.
an edge length of platinum (Pt) = 1.0 cm.
Then Volume= 1.0 cm×1.0 cm×1.0 cm=1cm^3
Then we have volume of the cube as 1cm^3
Given:
The density Pt = 21.45 g/cm3
the mass of a single Pt atom =3.240 x 10^-22 g
Then with 1atom of the platinum element, we can calculate the number of Pt atoms in the cube as
Density of pt/mass of a single Pt atom
=(21.45 /=3.240 x 10^-22)
=6.6×10^22atoms of Pt in the cube
B)Volume of cube V=4/3πr^3
V= 4/3 ×π×r^3
V= 4.19067r^3
r^3= V/4.19067
But volume is not total volume but just 74% of it, then With 74% of the space inside the cube is taken up by Pt atoms, then we need to find 74% of volume of the cube which is 1cm^3
74/100 ×1= 0.74cm^3
Then our new volume V is 0.74cm^3
r^3=0.74/4.19067×6.620 x 10^22
r^3=2.6674×10^-24
r= 3√2.6674×10^-24
r=1.4×10^-8m
ASAP 100 POINTS Which molecules carries instructions for inherited traits
A.DNA
B CARbohydrate
C.Protein
D.Lipid
Answer:
A.DNA
Explanation:
Ahaa Its gona be right
Answer:
D.N.A.
Explanation:
Hi student! Let me help you out on this question.
D.N.A. is the molecule which carries instructions for inherited traits.
[tex]\therefore,Option\quad A \quad is \quad correct[/tex]
Hope that this helped! have a good day ahead.
A lead ball is added to a graduated cylinder containing 50.6 ml of water, causing the level of the water to increase to 93.0 mL. What is the volume in milliliters of the lead ball, Vieras? Viead =
42.4 ml is the volume in milliliters of the lead ball if a lead ball is added to a graduated cylinder containing 50.6 ml of water.
What is a graduated cylinder?A tall narrow container with a volume scale is used especially for measuring liquids.
The graduated cylinder contains water
mL is a volume unit.
Water volume = 50.6 ml
The lead ball caused an increase in volume from 50.6 ml to 93.0 mL.
The new volume is the lead ball volume plus the original water volume :
Final volume = Vlead ball+ Water original volume
[tex]93.0 mL= V_(lead ball) +50.6 ml[/tex]
[tex]V_(lead ball) = 93.0 mL - 50.6 ml[/tex]
[tex]V_(lead ball) = 42.4 ml[/tex]
Hence, 42.4 ml is the volume in milliliters of the lead ball.
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Calculate 5.1234 + 0.033÷ 1.650 and report to the correct number of significant figures.
5.1434 contains 5 significant figures and 4 decimals.
What is a significant figure?All zeros that occur between any two non-zero digits are significant. For example, 108.0097 contains seven significant digits.
Calculation:
5.1234 + 0.033÷ 1.650 = 5.1434
5.1434 contains 5 significant figures and 4 decimals. 5.1434 rounded to 4 sig figs is 5.143, to 3 sig figs is 5.14, and to 2 sig figs is 5.1.
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Which of these is a benefit of including comments in your code
makes the app run faster
O helps other programmers understand your code
O improves the user interface
O makes your app more user friendly
A benefit of including comments in your code is that it helps other programmers understand your code.
What is a Code?These are numbers and letters which are used to identify a particular thing at a point in time.
Comments can be put in a code so as to enable others know and understand real intentions about it etc.
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Answer: O helps other programmers understand your code
Explanation: got it right on edgen
Consider the following reversible reaction:
2 CO(g) + O₂(g) 2CO₂(g). Describe a way to increase the CO concentration at equilibrium. Explain your reasoning.
The given equilibrium reaction indicates the reaction between carbon monoxide and the oxygen and forms carbon dioxide. In this reaction, by increasing the concentration of the carbon monoxide, the equilibrium shifts towards the right. Since, the reactant concentration increases, the equilibrium stress decreases the concentration of the reactants and therefore, the equilibrium shift towards the right side of the equation.
reaction indicates that carbon monoxide reacts with oxygen and forms carbon dioxide gas.
By increasing the concentration of carbon monoxide image, the equilibrium in the reaction shifts towards the right.
The effect of change of pressure, concentration and temperature on the state of equilibrium can be predicted with the help of a principle known as Le Chatelier's principle. Here by increasing the concentration of CO₂, the amount of CO formation can increase.
What is Le Chatelier's principle?If a system in equilibrium is subjected to a change in concentration, pressure or temperature, the equilibrium shifts in the direction that tends to reduce or to counteract the effect of change. When the concentration of any substance in equilibrium is increased, the equilibrium shifts in the direction which decreases the concentration of that substance.
On other hand, increasing the concentration of any of the products results in shifting the equilibrium in the backward reaction forming more products. So here increasing the amount of CO₂, shifts equilibrium in the backward direction and forms more amount of CO.
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3) The following reaction produces chlorine molecules:
Energy + HCl (g) + CINO3 (8) Cl₂ (8) + HNO3 (8)
a) Describe 4 ways you could increase the concentration of chlorine molecules.
b) How would cooling shift the equilibrium of this reaction?
The 4 ways to increase the concentration of chlorine molecules is listed below and the reaction will go into reverse if cooled.
What is Le Châtelier’s principle ?
Le Châtelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium.
Energy + HCl (g) + ClNO₃ ⇄ Cl₂ + HNO₃
a. So in this reaction when at equilibrium , To increase the concentration of Chlorine molecules
1. An increase in Temperature will favour the formation of Chlorine molecules.
2. Decrease in concentration of Chlorine , or partial removal of Chlorine will result the equation to go in forward direction.
3.An Increase in the concentration of HCl will favour formation of Chlorine molecules.
4.An Increase in the concentration of CINO₃ will also favour formation of Chlorine molecules.
b. The cooling would shift the reaction into backward direction as it is an endothermic reaction in forward state.
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Convert 26.02 x 1023 molecules of C2H8 to grams. Round your answer to the hundredths place.
No of molecules=26.02×10²³molecules
No of moles
26.02×10²³/6.023×10²³4.3molMolar mass
C2H82(12)+8(1)24+832g/molMass
Moles×Molar mass32(4.3)137.6g[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{Molecules}{Avagadro\:no}[/tex]
[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{26.02\times 10^{23}}{6.023\times 10^{23}}[/tex]
[tex]\\ \tt{:}\longrightarrow No\:of\:moles=4.32mol[/tex]
Molar mass of Ethane=32g/molWe need the mass
[tex]\\ \tt{:}\longrightarrow No\:of\:moles\times molar\:mass[/tex]
[tex]\\ \tt{:}\longrightarrow 32(4.32)[/tex]
[tex]\\ \tt{:}\longrightarrow 138.24g[/tex]
FLAG A nurse is preparing to administer morphine 0.05 mg/kg intermittent IV bolus to a newborn who weighs 3 kg. Available is morphine 0.5 mg/mL injection. How many mL should the nurse administer? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.)
The quantity of morphine, the nurse should administer is 0.3 ml.
What is morphine?Morphine is a drug which comes under the pain relieving drugs.
The quantity of morphine is 0.05 mg/kg
The weight of the baby is 3 kg.
Available morphine is 0.5 mg/mL.
0.05 x 3 = 0.15 mg
then, 0.15 mg / 0.5 = 0.3
Thus, the quantity of morphine, the nurse should administer is 0.3 ml.
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Question 11 of 30
During a reaction, the enthalpy of formation of an intermediate is -286
kJ/mol. During the reaction, 2 moles of the intermediate are produced. What
is the enthalpy value for this step of the reaction?
O A. -286 kJ
B. 572 kJ
OC. 286 kJ
OD. -572 kJ
By convention, the standard enthalpy of formation of all elements in their standard states are assumed to be zero. Here the enthalpy value for the intermediate formation step is -572 kJ. The correct option is D.
What is enthalpy of formation?The standard enthalpy of formation of a compound is defined as the enthalpy change accompanying the formation of one mole of the compound from its constituent elements, all the substances being in their standard states.
The symbol used to represent the standard enthalpy of formation is ΔfH⁰. The knowledge of standard enthalpies of various substances is useful for calculating the standard enthalpies of a reaction.
The overall energy difference between the reactants and products remains the same no matter how many intermediates there are in the reaction pathway.
The enthalpy value = 2 × -286 = -572 kJ
Thus the correct option is D.
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Which factors affect heat transfer between a warm and a cool substance?
the time it took to heat the substance, the area of contact, and the specific heats of the substances
O the amount of time of contact, the area of contact, and the specific heats of the substances
O the time it took to heat the substance, the area of the substances, and the specific heats of the substa
O the amount of time of contact, the area of the substances, and the specific heats of the substances
The amount of time of contact, the area of contact, and the specific heats of the substances. Hence, option A is correct.
What are specific heats?The heat in calories is required to raise the temperature of one gram of a substance one degree Celsius.
Factors that affect the rate of heat flow include the conductivity of the material, the temperature difference across the material, the thickness of the material, and the area of the material.
Different materials have greater or lesser resistance to heat transfer, making them better insulators or better conductors.
The amount of time of contact, the area of contact, and the specific heats of the substances.
Hence, option A is correct.
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Answer: The answer is C and D
B: If a substance undergoes a physical change, then it will retain most of its original properties because no new substance is formed.
C: If a substance undergoes a chemical change, then it will not retain its original properties because a new substance is formed.
Explanation: I took the test on edg
Could really use a few pointers on this question!
From the calculations, we can see that the theoretical yiled of NO2 is 100L of NO2
What is the theoretical yield?The theoretical yield is that calculated from the stoichiometry of the reaction.
We can see that 1 mole of O2 produced 2 moles of NO2. Thus;
2.23 moles of O2 will produce 4.46 moles of NO2
Since 1 mole of NO2 occupies 22.4 L
4.46 moles of NO2 occupies 100L of NO2
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Which scientist performed the cathode ray experiment leading to the discovery of electrons
The scientist that performed the cathode ray experiment leading to the discovery of electrons is J.J. Thomson.
What is a cathode ray?A cathode ray is a tube that contains negatively charged electrode( that is the cathode) which emits electrons when heated at a low pressure.
The cathode ray was used by the scientist, J.J. Thomson to find the ratio of charge to mass (e/m) of the electrons.
Therefore, the scientist that performed the cathode ray experiment leading to the discovery of electrons is J.J. Thomson.
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Part E
Tsunami evacuation plans often consider the elevation of the community and its distance from the shoreline when
deciding which towns to evacuate. How could this data help in building new homes and communities along coastal areas
that are prone to tsunamis?
Answer:
make the house elevated
A solution of the ionic salt
NaCI would have
pH.
an acidic
a basic
a neutral
Answer:
Neutral
Explanation:
NaCl aqueous solution is formed by NaOH and HCl.
NaOH is a base and HCl is an acid, so they go through neutralization process forming a neutral salt and water.
How many grams do 6.534e+24 molecules of phosphoric acid weigh?
Answer:
1,063 grams H₃PO₄
Explanation:
To find the mass of phosphoric acid (H₃PO₄), you should (1) convert molecules to moles (via Avogadro's number) and then (2) convert moles to grams (via molar mass from periodic table).
Molar Mass (H₃PO₄): 3(1.008 g/mol) + 30.974 g/mol + 4(15.998 g/mol)
Molar Mas (H₃PO₄): 97.99 g/mol
6.534 x 10²⁴ molecules H₃PO₄ 1 mole 97.99 g
--------------------------------------------- x ------------------------------------- x --------------
6.022 x 10²³ molecules 1 mole
= 1,063 grams H₃PO₄
A gas cylinder contains 5.0 kg of propane. How many propane molecules are in the cylinder? The Avogadro constant, L = 6.022 x 1023 mol^-1
A 6.8 × 10^22
B 7.2 x 10^22
C 6.8 × 10^25
D 7.2 x 10^25
[1 mark]
Answer:
Here's your answer.
M(C3H8) = 44 g/mol
n(C3H8) = 5000 (g)/44 (g/mol) = 113,6 mol
[tex] N = n \times N_{a} = 113,6 \times 6,02 \times {10}^{23} \\ \\ = 684,1 \times 10 ^{23} \sf{molecules} [/tex]
Hope it helps you from my sideb. The sedative Demerol hydrochloride has the formula
C15H22CINO2. How many grams are in 0.025 mole of
Demerol hydrochloride?
Dinitrogen oxide (or nitrous oxide), N₂O, also known as
laughing gas, is widely used as an anesthetic in dentistry.
The number of grams present in 0.025 mole of Demerol hydrochloride is 7.094 grams.
What is Demerol hydrochloride?It is a drug used in treating severe or moderate pain.
The moles are given = 0.025
The formula is C₁₅H₂₂CINO₂
The elements that present are C, H, Cl, N, O.
The molecular weight are given:
Carbon: 12.0107
Hydrogen: 1.00784
Chlorine: 35.453
Nitrogen: 14.007
Oxygen: 15.999
Multiply the molecular weight with moles and add them
(15 x 12.0107) + (22 x 1.00784) + (1 x 35.453) + (1 x 14.007) + (2 x 15.999) = 283.79098 grams per mole.
Now, multiply the number of moles given with the total molecular weight
283.79098 x 0.025 = 7.094
Thus, the number of grams are 7.094.
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Monosaccharides and disaccharides are what kind of molecules?
Answer:
They are small molecules
Explanation: Hope this helps
Answer: C) Carbohydrates
Explanation:
A) Lipids
B) Nucleic acids
C) Carbohydrates
D) Proteins
apex
the density of 190mg of a liquid is 0.0076g/cm calculate the volume in ml
[tex]\\ \rm\Rrightarrow Density=\dfrac{Mass}{Volume}[/tex]
[tex]\\ \rm\Rrightarrow Volume=\dfrac{Mass}{Density}[/tex]
[tex]\\ \rm\Rrightarrow Volume=\dfrac{0.19}{0.0076}[/tex]
[tex]\\ \rm\Rrightarrow Volume=25cm³[/tex]
[tex]\\ \rm\Rrightarrow Volume=25mL[/tex]
determine the number of gram of gas produced when 4.66 mole of water produced from the complete combustion of butane
.we can read the chemical preparation of the reaction as: "4 g of hydrogen react with 32 g of oxygen to give 36 g of water". :)
URGENT!!! Based on the following reaction, how much water is produced when oxygen react with 1 mole of C₂H8?
C₂H8 (g) + 40₂ (g) →2CO2 (g) + 4H₂O(g)
Answer:
4 moles
Explanation:
For every mole of deuteriomethane consumed, 4 moles of water are produced.
So, the answer is 4 moles
An atom of an element is shown by the model.
How is the model useful
Answer:
I believe it is useful as it shows how electrons are distributed in the shells (energy levels) of an iron atom. An atom is the smallest particle of an element that can take part in a chemical reaction. It contains the nucleus and the shells (energy levels). the nucleus contains protons and neutrons while the shells contain electrons.
Explanation:
How many moles of a gas can be contained in a 1600-cm° flask at 25°C and 75 kPa?
Volume=1600cm³=1.6dm³=1.6L
Temperature=25°C=273+25=298K
Pressure=75000Pa
Now
Apply ideal gas equation
PV=nRTn=PV/RTn=75000(1.6)/8.314(298)n=48.43molThe number of moles needed is
n=48.43mol.
Calculations
Given the values of the volume and temperature, we would convert them to the required units.
Volume=1600cm³=1.6dm³=1.6L
Temperature=25°C=273+25=298K
Pressure=75000Pa
We would use the ideal gas equation
PV=nRT
n=PV/RT
n=75000(1.6)/8.314(298)
n=48.43mol
Question 2
2C4H10 + 1302 -> 8CO2 + 10H₂O
If 2.46 g H₂O are produced by a reaction, how many moles of C4H10 were used?
Answer:
2 mole of C4H10 were used in this reaction.
Calculate the how many sodium atoms must react completely to give 33,6 dm³ hydro-
gen gas at STP.
2Na+ 2H₂O → 2NaOH + H₂(g)
To give 33.6 dm³ hydrogen gas at STP, 18.06 x 10²³ atoms of Na must react completely.
What is Mole concept ?A mole is a unit of measurement used to measure the amount of any fundamental entity (atoms, molecules, ions) present in the substance.
As according to the given equation, 2 moles (ie 12.04 x 10²³ atoms) of Na-atoms produces 1 mole (22.4 ltr) of H₂-gas.
Hence, to produce 33.6 ltr (equivalent to 33.6 dm³) of H₂-gas produced by ;
= 12.04 x 10²³ atoms of Na / 22.4 ltr of H₂-gas x 33.6 ltr
= 18.06 x 10²³ atoms of Na
Hence, To give 33.6 dm³ hydrogen gas at STP, 18.06 x 10²³ atoms of Na must react completely.
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What volume of 12M HCI is needed to prepare 250
of 0.20M HCI?
Answer: 4.2
Explanation:
[tex]M_{A}V_{A}=M_{B}V_{B}\\(12)V_{A}=(250)(0.20)\\V_{A}=\frac{(250)(0.20)}{12}=\boxed{4.2}[/tex]
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).
HCl + Fe + ____ + H²
Simple Way.
Hydrochloric acid + iron --> ______ + hydrogen gas.
• Answer this question, only if you know.
• Misuse of points will cost a report.
Answer:
This is a correct answer. 2HCL + Fe = FeCl2 + H2
Why we use cotton cloth to mop the floor?
Answer:
because cotton have a good absorbing quality and can absorb water more which is used to mop the floor
Explanation: