Answer:
The outer shell of the new star will start to expand.
Explanation:
The new star will continue to glow for millions or even billions of years. As it glows, hydrogen is converted into helium in the core by nuclear fusion. The core starts to become unstable and it starts to contract. The outer shell of the star, which is still mostly hydrogen, starts to expand.
Explanation provided by:
StarChild: Stars - NASA
Indicate the electron pair geometry and the molecular geometry for each of the six compounds. Compound Electron pair geometry Molecular geometry CO 2 CO2 linear linear BF 3 BF3 SO 2 SO2 trigonal planar bent SiCl 4 SiCl4 tetrahedral tetrahedral PF 3 PF3 tetrahedral trigonal pyramidal OF 2 OF2 tetrahedral bent
Answer:
CO2
Electron pair geometry- Linear
Molecular geometry- Linear
BF3
Electron pair geometry - Trigonal planar
Molecular geometry- trigonal planar
SO2
Electron geometry - Trigonal planar
Molecular geometry - bent
SiCl4
Electron geometry- tetrahedral
Molecular geometry - tetrahedral
PF3
Electron pair geometry - tetrahedral
Molecular geometry- trigonal pyramidal
OF2
Electron pair geometry- tetrahedral
Molecular geometry- bent
Explanation:
Considering the molecule CO2, there are two regions of electron density in the molecule positioned at an angle of 180 degrees from each other hence the molecule is linear.
For BF3, the three bond pairs are arranged at the corners of a triangle to give a trigonal planar geometry at a bond angle of 120 degrees.
SO2 has two bonding groups and one lone pair giving three regions of electron density and a trigonal planar electron pair geometry. Due to the distortion to geometry caused by the presence of a lone pair, the molecule is bent.
For SiCl4, the four bonding groups are arranged at the corners of a regular tetrahedron hence it is tetrahedral both in electron pair geometry and in molecular geometry.
PF3 molecule has four regions of electron density corresponding to tetrahedral electron pair geometry. The presence of the lone pair leads to a trigonal pyramidal molecular geometry.
For OF2, there are four regions of electron density around the central oxygen atom. Two bond pairs and two lone pairs leads to a tetrahedral electron pair geometry but a bent molecular geometry is observed due to the two lone pairs.
What kind of reaction is this? *
Na + C1, → NaCl
A chemist carefully measures the amount of heat needed to raise the temperature of a 894.0g sample of a pure substance from to −5.8°C to 17.5°C. The experiment shows that 4.90kJ of heat are needed. What can the chemist report for the specific heat capacity of the substance?
Answer:
C = 0.2349 J/ (g °C)
Explanation:
Mass, m = 894.0g
Initial Temperature = −5.8°C
Final Temperature = 17.5°C
Temperature change = 17.5°C - (−5.8°C) = 23.3
Heat, H = 4.90kJ = 4900 J
Specific heat capacit, C = ?
The relationship between these quantities is given by the equation;
H = mCΔT
C = H / mΔT
C = 4900 / (894)(23.3)
C = 0.2349 J/ (g °C)
Density of water calculation using a 10 mL graduated cylinder
10 mL graduated cylinder + 10 mL unknown liquid (g) 10 mL graduated cylinder (g) Volume of liquid (mL) Density (g/mL)
Trial 1 19.731 9.861 10.0
Trial 2 19.831 9.861 10.0
Trial 3 19.831 9.861 10.0
Trial 4 19.771 9.861 10.0
Trial 5 19.751 9.861 10.0
Required:
Calculate the average density for the gradudated cylinder measurements.
Answer:
Average density of the liquid = 0.992 g/mL
Explanation:
Density = mass/volume
mass of liquid = (mass of liquid + mass of cylinder) - mass of cylinder
Trial 1: mass of liquid = 19.731 - 9.861 = 9.87
volume of liquid = 10 mL
density of liquid = 9.87 g / 10 mL = 0.987 g/mL
Trial 2: mass of liquid = 19.831 - 9.861 = 9.97
volume of liquid = 10 mL
density of liquid = 9.97 g / 10 mL = 0.997 g/mL
Trial 3: mass of liquid = 19.831 - 9.861 = 9.97
volume of liquid = 10 mL
density of liquid = 9.97 g / 10 mL = 0.997 g/mL
Trial 4: mass of liquid = 19.771 - 9.861 = 9.91
volume of liquid = 10 mL
density of liquid = 9.91 g / 10 mL = 0.991 g/mL
Trial 5: mass of liquid = 19.751 - 9.861 = 9.89
volume of liquid = 10 mL
density of liquid = 9.89 g / 10 mL = 0.989 g/mL
Average density = (0.987 + 0.997 + 0.997 + 0.991 + 0.989)/5 = 4.961/5
Average density of the liquid = 0.992 g/mL
(ILL GIVE BREAINLIEST!! ) Which process(es) has steps called prophase, metaphase, anaphase, and telophase?
meiosis and mitosis
mitosis and fertilization
fertilization only
meiosis only
Answer:
mitosis and fertilization is a required answer.
Answer:
meiosis and mitosis
Explanation:
the difference is that meiosis goes through it twice.
Part A
Summarize your research, and describe the attributes of the savanna.
Answer:
Savanna regions have two distinct seasons - a wet season and a dry season. There is very little rain in the dry season. In the wet season vegetation grows, including lush green grasses and wooded areas.
Savannas are grasslands found in Africa, Australia, South America, and India. The climate is warm or hot. Savannas experience both dry and rainy seasons. Each year, savannas receive about 20 to 50 inches of rain in a span of six to eight months. The other months are dryer. There’s also a threat of wildfires because of the severe dryness during these months. Grasslands are true to their name because their vegetation is mostly grass. Savannas are home to a wide range of animals, including different species of beetles and insects, which many creatures consume. Squirrels, mice, elephants, gazelles, and antelopes are the plant-eating animals that live in the savanna. Hyenas, lions, and leopards are some of the meat-eating animals in these areas. Some of the nonliving components of the system include very porous soil that allows water to drain easily.
Why are acids called proton donors?
Explain the order of dielectric constants for the following pairs of liquids. a) Carbon tetrachloride (2.2), chloroform (4.8) b) Ethanol (24.3) and methanol (32.6) c) Acetone (20.7) and formamide (110.0)
Answer:
See explanation
Explanation:
Let us have it behind our minds that the dielectric constant reveals the degree of polarity of a molecule. This implies that the more polar a molecule is, the greater its dielectric constant.
Chloroform is a polar molecule while carbon tetrachloride is a nonpolar molecule due to its symmetrical nature. Thus Chloroform has a greater degree of polarity and consequently a higher dielectric constant.
Methanol is more polar than ethanol because polarity of the molecule decreases as more CH2s are added to the molecule, that is, polarity of the molecule decreases with increase in the length of the carbon chain. Since methanol is more polar than ethanol, it should have a greater dielectric constant.
Again, the presence of more akyl groups in acetone makes it less polar than formamide. Consequently, formamide has a greater dielectric constant than acetone.
How many moles of hydrogen atoms are in 0.213 moles of C6H1804
Answer: 3.834
Explanation: 18*0.213
A standard 10.00 g mass is weighed on an analytical balance 100 times. The average and standard deviation obtained gives 10.12 ± 0.03 g. A calibration service is called. After the balance is recalibrated, the new measurements show 10.00 ± 0.03 g. Did the recalibration result in improved accuracy or precision?
Answer:
There was an improvement in accuracy. There was no change in precision.
Explanation:
The average mass after recalibration is closer to the mass of the standard, so the recalibration improved the accuracy (the measurement is closer to an accepted 'true' value).
The standard deviation did not change, so the precision (or how disperse the measurements are) was not affected.
12) How many moles of CO can be produced from
10.0 mol of CO2
Answer:
5
Explanation:
There are 2 moles of CO in each CO2. 10 ÷ 2 = 5
There diagrams imply that’s
A TISSUEs are always rectangular
B tissues are made up of cells
C Tissues all look the same
D tissues have the same Function
Answer:
b
Explanation:
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A mixture of cyclopropane (C3H6) and oxygen (O2) is sometimes used as a general anesthetic. In a mixture, the partial pressures of cyclopropane and oxygen are 170. torr and 570. torr, respectively. Calculate the ratio of the moles of oxygen to the moles of cyclopropane in the mixture.
Answer:
0.30
Explanation:
Provided that the volume and pressure remains constant
[(Pressure of cyclopropane)/ (Pressure of Oxygen)] = [(no. Of moles of cyclopropane)/(no. Of moles of Oxygen)]
Pressure of cyclopropane= 170. torr
Pressure of Oxygen= 570. torr
If we substitute the values
[(no. Of moles of cyclopropane)/(no. Of moles of Oxygen)] = 170/570
[(no. Of moles of cyclopropane)/(no. Of moles of Oxygen)] = 0.30
Hence, the ratio of the moles of oxygen to the moles of cyclopropane in the mixture is 0.30
PLEASE HELPPP!!! Calculate the mass (in grams) of lithium hydroxide that would be needed to produce 8.03 mol of
lithium sulfate in the reaction below.
2 LIOH + H2S04 -> Li2SO4 + 2 H20
Answer:
385g LiOH
Explanation:
Assuming the equation is balanced...
(8.03 mol Li2SO4) x (2 LiOH/ 1 Li2SO4)
= 16.1 mol LiOH ;
16.1 mol LiOH x (24g LiOH/ 1 mole LiOH) = 385g LiOH
The number of moles of LiOH needed to produce 8.03 moles is 16.06 moles. One mole of LiOH weighs, 23 g/mol. Hence, 16.06 moles weighs, 369.3 g.
What is lithium sulphate ?Lithium sulphate is an ionic compound formed by the donation of electron from the lithium metal to the sulphate group. It is formed by the reaction of lithium hydroxide with sulphuric acid.
As per the given balanced chemical equation of the reaction, the 2 moles of lithium hydroxide LiOH gives one mole of lithium sulphate. Then, number of moles of LiOH needed to give 8.03 mol of the product is:
2 × 8.03 = 16.06 mol.
Molar mass of LiOH = 23 g/mol.
mass of 16.06 moles of LiOH = 23 ×16.06 = 369.3 g.
Therefore, the required mass LiOH is 369.3 g.
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I need some help to determine the mole and grams pls I would really appreciate the help
Answer:
[tex]n_{FeS}=0.686molFeS \\\\n_{H_2S}=23.3gH_2S[/tex]
Explanation:
Hello!
In this case, according to the given chemical reaction, it is possible to apply the following stoichiometric setups in order to compute the moles of reacting FeS and the grams of produced H2S, given the mass of HCl (molar mass = 36.46 g/mol) as shown below:
[tex]n_{FeS}=50.0gHCl*\frac{1molHCl}{36.46gHCl}*\frac{1molFeS}{2molHCl}\\\\n_{FeS}=0.686molFeS \\\\\\m_{H_2S}=50.0gHCl*\frac{1molHCl}{36.46gHCl}*\frac{1molH_2S}{2molHCl}*\frac{34.04gH_2S}{1molH_2S} \\\\n_{H_2S}=23.3gH_2S[/tex]
Best regards!
Pls help!!!!!! In your own words, explain how chemists properly represent the law of conservation of matter in their chemical
equations.
Answer:
They represent it by ensuring that the number of atoms of each element (matter) in the reactant side is the same as the product side
Explanation:
The law of conservation of matter stated that matter can neither be created nor destroyed. Chemical equations involve combining atoms of elements. The compounds combined by chemists are called REACTANTS while the produced compounds are called PRODUCTS.
In order to conform to the law of conservation of matter, the same quantity of matter present in the reactants must be present in the products. This means that the number of atoms of each element (matter) in the reactant side must be the same as the product side. For example;
C6H12O6 + 6O2 → 6CO2 + 6H2O
In this chemical equation for photosynthesis, number of atoms in the reactant side (6 carbon, 12 hydrogen, 18 oxygen) are the same as that in the product side (6 carbon, 12 hydrogen, 18 oxygen), hence, this obeys the law of conservation of mass.
In a nutshell, chemists chemists properly represent the law of conservation of matter in their chemical equations by making sure that same number of atoms of reactants is present in the products.
5.6 g of Iron reacts with excess fluorine gas.
The mass of iron fluoride produced is 11.3 g
What is the formula of the iron fluoride?
Answer: FeF3 Iron(III) fluoride
Explanation: 5.6 g = 1/10 mole Fe
11.3-5.6g F = 5.7 = 3/10 mole F
Which example is a long-term environmental change?
O La Niña
O EI Nino
O climate change
O small asteroid impact
C
The orbit closest to the nucleus has ___________ energy.
Answer:
inonic bonds with cavalent bonds
Explanation:
ionic bonds
A student is building a model of the layers of the Earth. Which material would best represent the crust?
a:grouping of magnetic balls
b:Styrofoam packing pellets
C:Bag of shredded paper
d:Thin layer of plaster
Answer:
d
Explanation:
The material that represents the crust is option d. Thin layer of plaster.
What is the crust and which material should be considered for it?It is the outermost shell of a planet i.e. terrestrial. The crust of the earth should be split into older, thicker continental crust, etc. Also, it is made of solid rocks and minerals. Due to this, the thin plaster layer represents the material for the crust.
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A sample of iron, which has a specific heat capacity of 0.449 Jg^-1℃^-1, is put into a calorimeter (see sketch at right) that contains 100.0 g of water. The iron sample starts off at container 93.3 °C and the temperature of the water starts off at 22.0 °C. When the temperature of the water stops changing it's 25.7 °C. The pressure remains constant at 1 atm.
Required:
Calculate the mass of the iron sample. Be sure your answer is rounded to 2 significant digits.
Answer:
[tex]m_{iron}=32.1g[/tex]
Explanation:
Hello!
In this case, since the interaction between hot iron and cold water allows the heat transfer from iron to water and therefore we can write up the following energetic equation:
[tex]Q_{iron}+Q_{water}=0[/tex]
Whereas the heat terms can be written in terms of mass, specific heat and temperature change:
[tex]m_{iron}C_{iron}(T_f-T_{iron}) + m_{water}C_{water}(T_f-T_{water}) = 0[/tex]
So we solve for the mass of iron as follows:
[tex]m_{iron} = \frac{m_{water}C_{water}(T_f-T_{water})}{C_{iron}(T_f-T_{iron}) }[/tex]
Now, we plug in the given data to obtain:
[tex]m_{iron} = \frac{-100g*0.449\frac{J}{g\°C} (25.7\°C-22.0\°C)}{0.449\frac{J}{g\°C} (25.7\°C-93.3\°C) }[/tex]
[tex]m_{iron}=32.1g[/tex]
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how many moles are in a 25.0 grams of carbon dioxide
answer:44.0095
Explanation:
sana makatulong
Answer:
44.0095
Explanation:
We assume you are converting between grams CO2 and mole. You can view more details on each measurement unit: molecular weight of CO2 or mol This compound is also known as Carbon Dioxide. The SI base unit for amount of substance is the mole.
Did i answer these right??
Breathing equipment used by rescue workers needs to capture the CO2 the humans breath out and produce O2 for them to breath in, like a plant during photosynthesis. One compound capable of doing this is potassium superoxide (KO2), which produces the salt by-product potassium carbonate. What is the balanced chemical equation for this reaction? Don't include states of matter.
Answer: [tex]4KO_2+2CO_2\rightarrow 2K_2CO_3+3O_2[/tex]
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced chemical equation for reaction of potassium superoxide with carbon dioxide to produce oxygen and potassium carbonate will be:
[tex]4KO_2+2CO_2\rightarrow 2K_2CO_3+3O_2[/tex]
Fill in the coefficient needed to make the equation balanced.
1. _______ Na + Cl2 → ______NaCl
a. 2, 2
b. 2, 3
c. 2, 1
d. 2, 4
2. _______Al + _______S → Al2S3
a. 2, 2
b. 2, 3
c. 2, 4
d. 2, 6
3. ______ H2 + O2 → ______H2O
A. 2, 2
b. 2, 3
c. 2, 4
d. 2, 8
4. _______Fe + ______O2 → ______Fe2O3
a. 4, 2, 2
b. 4, 2, 1
c. 4, 3, 2
d. 4, 3, 1
Answer:
1 a
2 b
3 a
4. c
Explanation:
How does latitude affect water temperature? Choose ALL that apply Lesson 2.05 none of the choices Temperatures are greatest at low altitudes because of the proximity to the equator As you move to higher latitudes approaching the poles, the temperature decreases. Temperatures are lowest at low altitudes because of the proximity to the equator
Answer:
I think it's option 3 (From top to bottom)
Explanation:
When the water is at a higher altitude there's only about 40 percent heat that the equator does.
(30 POINTS) Which order shows the levels of organization from largest to smallest?
organism, organ system, cell, organ, tissue
organism, tissue, organ system, organ, cell
organism, organ, organ system, cell, tissue
organism, organ system, organ, tissue, cell
Answer:
cell,tissue,organ,organ system,organism
explain how the particles of a substance change as a substance changes from a solid to a liquid to a gas.
Answer:
Some substances can change from the solid state to the gas state without ever becoming a liquid. During this process, known as sublimation, the sur- face particles of the solid gain enough energy to become a gas.When dry ice becomes a gas, it absorbs thermal energy from water vapor in the air.
Explanation:
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.
please help. it’s my last question.
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
