Answer:
Molar mass of Ca = 40 g / mol , given 123 g Ca is 123/40= 3.075 moles,
1 mole = 6.022 * 10^23 atoms, so 3.075 moles Ca= 18.51*10^23 atoms
Explanation:
The number of atoms present in 123 g of calcium is 18.51 x 10²³ atoms.
What is calcium?Calcium is an element present in the periodic table. It is very much needed for the strength of the bones and teeth.
"Molar mass of many compounds can be calculated by dividing the mass of the compound by the number of moles of the compound."
"The mole is a SI unit of measurement that is used to calculate the quantity of any substance".
First, calculate the moles
Moles = mass / molar mass
Molar mass of Ca = 40 g / mol
Given 123 g Ca is mass
123 / 40 = 3.075 moles,
1 mole = 6.022 x 10²³ atoms,
6.022 x 10²³ is the Avogadro number. It equals to one mole.
So 3.075 moles Ca= 18.51 x 10²³ atoms.
Thus, the number of atoms present in 123 g of calcium is 18.51 x 10²³ atoms.
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a reaction vessel contains a small piece of magnesium metal and air (20%) of which is oxygen gas. The mixture is ignited and burns with a burst of light and heat, producing solid magneisum oxide. The mass of mgO, however, is less than the initital mass of magnesium and oxygen combined. What loss of mass
Answer: see below
Explanation:
Mg burning in air gives MgO and a smaller amount of Mg3N2
2Mg+O2=2MgO. 2*24.3+32=2*40.3
3Mg+N2=Mg3N2
Ignoring the nitride, MgO loss of mass during the reaction can be ascribed to
(1) relativistic loss as energy (too small to be measurable)
(2) During the reaction, which is strongly exothermic, a fraction f the material is blown off as tiny particles which adhere to the vessel.
Help solve please, it’s due in less than an hour or so.
sorry i can only figure out 1 but the answer is
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124
hope you do good on your test :D
3. A gram food sample is burned completely in a calorimeter that contains 1000. of water The temperature of the water increases 23.65 degrees * C . How many Calories does the food have per gram ?
The food has 23629.64 cal
Further explanationGiven
mass = 1000 g of water
temperature increases 23.65 * C
Required
The energy of the food
Solution
Heat absorbed by water :
Q = m . c . Δt
Q = 1000 g x 4.184 J/g°C x 23.65 °C
Q = 98951.6 J
1 Joules = 0.2388 Calories
98951.6 J = 23629.64 cal
Would you consider an aquifer a renewable resource? Why or why not?
Answer:
an aquifer is a renewable resource
Explanation:
Aquifers are defined as the groundwater found deep in the layers of rocks.
An aquifer is considered as a renewable resource because groundwater is renewed over time. Aquifers are water resources and follow hydrological cycle through which it can renew itself.
Some of the deep aquifers are considered as nonrenewable resource because it toll hundreds of years to accumulate.
Hence, the correct answer is yes an aquifer is a renewable resource except some deep aquifers.
Consider a reaction that connects the ends of a chain of carbons to form a ring. The closure of the ring results in the formation of a new chemical bond, with the bonding electrons going into a bonding sigma molecular orbital at a lower energy. Which of the following statements correctly describes the resulting enthalpy, entropy, and heat changes? Mark all that are correct.
A. The entropy of the surroundings decreases (AS surr < 0) because the closure of the ring results in fewer conformations for the system.
B. The system releases energy to the environment, because its internal energy decreases.
C. The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.
D. The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.
E. The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.
Answer:
The system releases energy to the environment, because its internal energy decreases.
The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.
The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.
The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.
Explanation:
Now we know that when a reaction is exothermic heat is given off. In this case, we have a reaction that connects the ends of a chain of carbons to form a ring. The bonding electrons now move into a lower energy bonding sigma molecular orbital.
This leads to a decrease in the entropy and enthalpy of the system because energy is given off, the closure of the ring reduces the number of conformations the ring can adopt and the electrons that form the bond enter an orbital that is at a lower energy.
The entropy of the surroundings is increased as energy is given out. The surroundings absorb heat released by the reaction, and become more disordered.
Which of these describes the essential conclusion of the Rutherford experiment? The atom contains a very small nucleus that contains most of its mass. The proton is positively charged and the neutron has no charge? Atoms are solid spheres with electrons suspended in them like chocolate chips in a cookie. Mass is neither made nor consumed in a chemical reaction.
Answer:
The atom contains a vey small small nucleus that contains most of its mass.
Explanation:
The Rutherford gold leaf experiment concluded that most (99%) of all the mass of an atom is in the nucleus of the atom, that the nucleus is very small (105 times small than the size of the atom) and that is is positively charged.
How many molecules are in 97.21 grams of Sodium Chloride (NaCl)?
Use the periodic table to select the element that best fits each of the following descriptions.
Noble gas:
O oxygen
O chlorine
Okrypton
Answer:
Krypton
Explanation:
The picture has my question
Answer:
b or c
Explanation:
Which types of energy transformations does a television make?
Electrical energy to energy of motion and heat energy
Electrical energy to heat energy and light energy
Electrical energy to sound energy and energy of motion
Electrical energy to sound energy and light energy
Answer:
d.
Explanation:
the electricity is why we can hear sounds from the television and see it
ou are a work study for the chemistry department. Your supervisor has just asked you to prepare 500 mL of 3 M HCl for tomorrow’s undergraduate experiment. In the stockroom explorer, you will find a cabinet called "stock solutions". Open this cabinet to find a 2.5 L bottled labeled "11.6 M HCl". The concentration of the HCl is 11.6 M. Please prepare a flask
Answer:
Add to a 500mL volumetric flask 300mL of water, the 129mL of the 11.6M HCl solution and then complete to volume with water
Explanation:
To make 500mL = 0.500L of a 3M HCl from the 11.6M HCl stock we need first to find the moles of HCl we need:
Moles HCl:
0.500L * (3mol / L) = 1.5 moles of HCl are needed
These moles are obtained from the 11.6M HCl solution. The volume required is:
1.5mol * (1L / 11.6moles HCl) = 0.129L = 129mL must be added to the solution.
That means to prepare the 500mL of the 3M HCl you need to:
Add to a 500mL volumetric flask 300mL of water, the 129mL of the 11.6M HCl solution and then complete to volume with water
Answer:
Calculation: 11.6 M × V = 3.0 M × 0.500 liters
V = 0.13 liters
Steps for dilution:
Measure out 0.13 liters of the concentrated solution of 11.6 M HCl using a volumetric pipet.
Transfer this into solution into a 500 milliliter volumetric flask.
Add water to the flask until it reaches a total volume of 500 milliliters.
Solution: V = 0.13 liters
Explanation:
What important function do currents and areas of upwelling provide for living things
in the sea?
Recycles the ocean water through evaporation and precipitation
Brings nutrients up from deeper water for use by organisms
Mixes land and sea organisms to broaden the food web
Allows Earth to have weather and climate changes
Pls answer this two ASAP PLSSSSSSSS
Answer:
1. aa
2. They have similar DNA
Explanation:
1. According to the question 1, wrinkled seeds (A) are dominant over round seeds (a) in pea plants. This means that, based on the law of dominance proposed by Mendel, wrinkled seeds will be expressed over round seeds in a heterozygous state (Aa).
However, since the round seed phenotype is a recessive trait, it will only be expressed when the alleles for round seeds (a) are the same in the gene i.e. aa genotype.
2. Based on the information in question 2, Ricky, who is working on a family tree for his school project, realizes that his close relatives all look similar in the pictures he collected. This is possible because of the SIMILARITY OF THEIR DNA (genetic material). Note that, relatives are connected by the genes that are inherited from one another, hence, they possess a similar DNA, which is the most valid reason for the resemblance.
Don’t skip please!!! I need help
Given
Atomic symbol
Required
Atomic composition
Solution
Atomic number = number of protons = number of electrons
Mass Number (A) is the sum of protons and neutrons
Number of protons and Number of Neutrons in nucleus
Number of electrons in the shell
From the picture:
protons = 3
neutrons = 4
electrons = 3
atomic number = protons = electrons = 3
mass number = protons + neutrons = 3+4 = 7
2. What is the final temperature when a 32.0 g piece of diamond at 33.5°C is heated with 360 J of energy?
(Cp = 0.509
Answer:
55.6 °C
Explanation:
From the question given above, the following data were obtained:
Mass (M) of diamond = 32.0 g
Initial temperature (T₁) = 33.5°C
Heat (Q) required = 360 J
Specific heat capacity (C) of diamond = 0.509 J/gºC
Final temperature (T₂) =?
Next, we shall determine the change in temperature. This can be obtained as follow:
The final temperature can be obtained as follow:
Mass (M) of diamond = 32.0 g
Heat (Q) required = 360 J
Specific heat capacity (C) of diamond = 0.509 J/gºC
Change in temperature (ΔT ) =?
Q = MCΔT
360 = 32 × 0.509 × ΔT
360 = 16.288 × ΔT
Divide both side by 16.288
ΔT = 360 / 16.288
ΔT = 22.1 °C
Finally, we shall determine the final temperature. This can be obtained as follow:
Initial temperature (T₁) = 33.5°C
Change in temperature (ΔT ) = 22.1 °C
Final temperature (T₂) =?
ΔT = T₂ – T₁
22.1 = T₂ – 33.5
Collect like terms
22.1 + 33.5 = T₂
T₂ = 55.6 °C
Therefore, the final temperature is 55.6 °C.
Why is one side of the moon called "the dark side of the moon"?
Answer:
Option C
Explanation:
The answer is option C or "The amount of time it takes to rotate around it's axis is the same amount of time it takes to revolve around Earth."Remember that the Earth and the Moons amount of time to make a full rotation is almost in sync and they're two sides of the moon, one side we do not see and that's because that side is currently faced away from the Earth which is called the dark side of the moon. Each side has two weeks oh night, and two weeks of day because of how long it takes the moon to revolve, so while we have a side towards the Earth which is illuminated by the sun we have another pointing away in the dark.
Hope this helps.
what kind of crystalline solid is graphite?
Answer:
Covalent-network (also called atomic) solids—Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well. Characterized as being very hard with very high melting points and being poor conductors. Examples of this type of solid are diamond and graphite, and the fullerenes.
I hope it's helpful!
Answer:
network solid
Explanation:
Which of the following is an example of a physical change, but not a chemical change?
Answer:
Boiling Water
Explanation:
Boiling water is an example of physical change and not and not a chemical change because the water vapor still has the same molecular structure as liquid water.If the bubbles were caused by the decomposition of a molecule into gas then boiling would be a chemical change.
Answer:
A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding
Explanation:
How many atoms are in 0.580 moles of CO2?
Answer:
[tex]1.05x10^{24}atoms[/tex]
Explanation:
Hello!
In this case, according to the definition of the Avogadro's number, it is possible to realize that one molecule of CO2 contains 3 moles of atoms, one of carbon and two of oxygen, thus, we have:
[tex]0.580molCO_2*\frac{3mol\ atoms}{1molCO_2} =1.74mol\ atoms[/tex]
Then, we use the Avogadro's number to obtain:
[tex]1.74mol\ atoms*\frac{6.022x10^{23}atoms}{1mol\ atoms} \\\\1.05x10^{24}atoms[/tex]
Best regards!
If you were to burn a candle inside of a closed jar and the mass of the
closed jar and candle was 50 grams to begin with, what would the mass of
the jar and smoke be after the candle is done burning?
Answer:
50g
Explanation:
At the end of the burning process, the mass of the jar and smoke should be 50g after the candle burning is done.
In most systems, the law of conservation of matter finds expression. According to this law "matter is neither created nor destroyed but atoms are rearranged".
In this kind of system, no matter is allowed to escaped and the starting mass of the reactants compared to that of the product will be the same.
What is the answer for number 9 in the Half-life gizmo activity B.
35.2 J of heat is
applied to 16.0 g
of a substance.
Temp rises by 7.2
K. Specific Heat?
The specific heat : c = 0.306 J/g K
Further explanationGiven
Heat = 35.2 J
Mass = 16 g
Temperature difference : 7.2 K =
Required
The specific heat
Solution
Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
Input the value :
c = Q / m.∆T
c = 35.2 / 16 x 7.2
c = 0.306 J/g K
Calculate the number of moles in 15.5g of CaSO4.5H2O
Answer:
No. of moles = 0.0685
Explanation:
Given mass, m = 15.5g
We need to find the number of moles in 15.5 g of CaSO₄.5H2O
First, we find the mass of CaSO₄.5H2O.
M = (1×40)+(1×32)+(4×16)+(5×18)
M = 226 g/mol
We know that,
Number of moles = given mass/molar mass
[tex]n=\dfrac{15.5\ g}{226\ g/mol}\\\\n=0.0685\ \text{mol}[/tex]
Hence, there are 0.0685 moles in 15.5 g of CaSO₄.5H2O.
Police investigating the scene of a sexual assault recover a large blanket that they believe may contain useful physical evidence. They take it to the laboratory of forensic serologist Scott Alden, asking him to test it for the presence of semen. Noticing faint pink stains on the blanket, Scott asks the investigating detective if he is aware of anything that might recently have been spilled on the blanket. The detective reports that an overturned bowl of grapes and watermelon was found at the scene, as well as a broken glass that had contained wine. After the detective departs, Scott chooses and administers what he considers the best test for analysing the piece of evidence in his possession. Three minutes after completion of the test, the blanket shows a positive reaction. What test did Scott choose, and what was his conclusion? Explain your answer.
Answer:
Acid Phosphatase (AP) Test
Explanation:
Acid phosphate is an enzyme that is found in the body. It is secreted majorly by the prostrate gland into the seminal fluid. The acid phosphatase test is used to test for the presence of semen in items.
Scott chose the acid phosphatase test because it is very useful in testing for semen on large items such as blankets. The reaction time for an acid phosphatase test for semen is less than 30 seconds. Seeing that the test was completed in three minutes, Scott concluded that the positive reaction was as a result of some other fluid.
The detectives reported that an overturned bowl of grapes and watermelon was found at the scene as well as a broken glass that had contained wine. Scott knew that some fruit juices like that of watermelon give a positive reaction to the acid phosphatase test but with more time that of the semen fluid because the reaction is a very slow one.
Scott concluded that there was no presence of semen on the blanket and therefore there was no sexual assault.
How does the appearance of a substance change when it
changes phase?
Answer:
Melting: the substance changes back from the solid to the liquid. Condensation: the substance changes from a gas to a liquid. Vaporization: the substance changes from a liquid to a gas. Sublimation: the substance changes directly from a solid to a gas without going through the liquid phase.
Explanation:
The change in appearance of a substance when it changes its phase includes :
Change in volume Change in texture and Change in shapeChange in volume : when a liquid substance is heated to its boiling point ( vaporization) the volume of the liquid substance will change when it turns into gas because gases have no definite volume or shape.
Change in Texture: When water freezes it changes its state from a liquid state to a solid state, also the appearance of the liquid water will undergo changes in its texture when it is in its' solid state ( i.e. the texture of ice is not exactly the texture of liquid water )
Change in shape : when a solid substance changes its state from solid to gas ( sublimation ) the shape of the solid substance will be lost during the phase change.
Hence we can conclude that the change in the appearance of a substance when it changes its phase include. Change in volume, Change in texture and Change in shape.
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Answer:
water
Explanation:
water is made up of both hydrogen and oxygen (h2o)
There is a third bromobutene structure that could have been formed in the addition of HBr to butadiene: cis-1-bromor-2-butene (the cis isomer of structure 2). Draw this structure. Would you predict (no calculation) its heat of formation to be more or less negative that the trans isomer? Explain.
Answer:
its less negative hope I helped buster
Because trans isomers are more stable than cis isomers, the cis isomer will have a less negative heat of formation than the trans isomer.
What are cis- and trans- isomers?Cis- and trans isomers are compounds that have different configurations in space because of the presence of a rigid structure or functional groups in their molecule.
Cis atoms have functional groups on the same side.
Trans isomers have functional groups on alternate different.
The structure of cis-1-bromor-2-butene is attached.
Generally, trans isomers are more stable than cis isomers..
Stable compounds have more negative heat of formation while unstable compounds have less negative heat of formation.
Therefore, the cis isomer will have a less negative heat of formation than the trans isomer.
Learn more about cis and trans isomers at: https://brainly.com/question/4625349
Which orbital is partially filled in the Zirconium (ZI) atom?
Answer:
4d orbital.
Explanation:
Hello!
In this case, since zirconium's atomic number is 40, we fill in the electron configuration up to 40 as shown below:
[tex]1s^2,2s^2,2p^6, 3s^2,3p^6,4s^2,3d^{10},4p^6,5s^2,4d^2[/tex]
Thus, the orbital 4d is partially filled.
Best regards!
Pls answer this ASAP thank you
Answer:
The anwer is not D the anwer is A
Explanation:
If an oxygen molecule is moving at 4.78 x 104
cm.s-, what is its speed in mi hrl?
Show work please
Answer: 1075.5 mph
Explanation:anything moving at 4.78*10^4 cm/sec
equivalent to
cm —> miles = 1/1.6*10^5
sec —> hr = 1/3600
[4.78*10^4]*3600/1.6*10^5 = 1075.5 mph