Answer:
The temperature at which a substance changes from the liq- uid state to the solid state is called the freezing point. The freez- ing point of the liquid state of a substance is the same temperature as the melting point of the solid state. For example, solid water melts at 0°C and liquid water freezes at 0°C.
Explanation:
A student observes the chemical process described by this equation:
4Al + 3O2 → 2Al2O3
How does the mass of the new substance compare to the total mass of the starting materials?
Answer:
Both are equal
Explanation:
Mass of starting material i.e Aluminium is [tex]4.480 * 10^{-23}[/tex] grams
The weight of oxygen is [tex]2.65 * 10^{-23}[/tex]
There are 4 atoms of aluminium and 3 atoms of oxygen
Thus, the total mass of starting material is
[tex]4 *[/tex] mass of one atom of aluminium [tex]+ 6 *[/tex] mass of one atom of oxygen
[tex]4 * 4.480 * 10^{-23} + 6* 2.65 * 10^{-23}[/tex]
[tex]35.1 * 10^{-23}[/tex] grams
Mass of new substance is also equal to
[tex]4 *[/tex] mass of one atom of aluminium [tex]+ 6 *[/tex] mass of one atom of oxygen
[tex]4 * 4.480 * 10^{-23} + 6* 2.65 * 10^{-23}[/tex]
[tex]35.1 * 10^{-23}[/tex] grams
Why did the United States government set aside land for the first national parks?
A.
They wanted to settle the west as quickly as possible.
B.
They worried people would destroy the animals and land.
C.
They worried Native Americans wouldn’t have anywhere to go.
D.
They wanted to make sure all citizens would get a piece of land.
Answer:
b
Explanation:
hope it helps
Do metals or nonmetals have the greatest tendency to lose electrons and become positive ions?
Answer:
The metals have the tedency to lose electrons and become positive ions
Explanation:
In order to attain noble gases electronic configuration, metals of group I A lose one electron and II A lose 2 electrons with ionization energy.
Of the following chemical properties , which one is not one that Covalent compounds DO NOT have ?
a
They share electrons between their elements.
b
They have weaker bonds.
c
They have relatviely higher melting and boiling points.
d
Many of these compounds are usallly liquids or gases at room temperature.
Answer:
D. They are usually liquids or gases at room temperature.
Explanation:
Covalent compounds have covalent bonds, meaning that they share electrons between elements and have relatively higher melting melting and boiling points due to the strength of their bonds. However covalent bonds are weaker than ionic bonds which is why B is correct. D is the only incorrect one because it is incorrect and contradicts point C. If a substance has a high melting/boiling point than it is much more likely to be solid at room temperature because of the high temperature it needs to pass in order to be a liquid or gas.
Hope this helped!
What are all of the possible products of the electrolysis of Sodium Chloride in aqueous solution of water when the electrodes are made of copper?
A photo has been provided to show what is happening
Answer:
HDHERFEHFFFHRF
Explanation:
A 52-gram sample of water that has an initial temperature of 10.0 °C absorbs 4,130 joules. If the specific heat of water is 4.184 J/(g °C), what is the final temperature of the water? (4 points) Group of answer choices 11 °C 19 °C 29 °C 51 °C
Answer:
28.98°C
Explanation:
Mass = 52g
Initial temperature (T1) = 10°C
Final temperature (T2) = ?
Heat energy (Q) = 4130J
Specific heat capacity of water = 4.184J/g°C
Heat energy (Q) = mc∇T
Q = heat energy
M = mass of the substance
C = specific heat capacity of the substance
∇T = change in temperature (T2 - T1)
Q = mc∇T
4130 = 52 * 4.184 * (T2 - 10)
4130 = 217.568 * ( T2 - 10)
4130 = 217.568T2 - 2175.68
217.568T2 = 4130 + 2175.68
217.57T2 = 6305.68
T2 = 6305.68 / 217.57
T2 = 28.98°C
Final temperature is 28.98°C
If is known how deep the water table in an area is, it is known how deep to dig to reach
Pores
The unsaturated zone
Solid rock
Groundwater
Answer:
grond water
Explanation:
What is the volume of solution (in mL) produced when 91.80g of Mg(OH)2 are used
to produce a 0.7M solution? Record your answer to 1 decimal places.
Answer: The volume of solution is 2248 ml
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in ml
moles of [tex]Mg(OH)_2[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{91.80g}{58.32g/mol}=1.574mol[/tex]
Now put all the given values in the formula of molality, we get
[tex]0.7=\frac{1.574\times 1000}{V_s}[/tex]
[tex]V_s=\frac{1.574\times 1000}{0.7}=2248ml[/tex]
Therefore, the volume of solution is 2248 ml
Compare and contrast the dynamics of energy transfer between the Eocene Period and the Cryogenian Period. In which period would you say that Earth's system is experiencing a net gain in energy and in which period would you say that Earth's system is experiencing a net loss in energy
Answer:
The Eocene Period is experiencing net gain in energy while Cryogenian Period is experiencing a net loss in energy.
Explanation:
In Eocene Period, the population of mammals such as horses , whales and bats etc were high due to the presence of high amount of food and good atmospheric condition such as high temperature while the population of animals were low in Cryogenian Period due to the presence of very low temperature which experiencing loss of energy. Most of area of the earth consist of icy desert.
A gas occupies a volume of 2.45 L at a pressure of 1.03 atm. What volume will the
gas occupy if the pressure changes to 0.980 atm and the temperature remains
unchanged? Show your work in the space below. *
Answer:
2.58 L
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
At constant temperature, if the pressure of the gas decreases to the given value, the volume increases to 2.58L.
What is Boyle's law?Boyle's law simply states that "the volume of any given quantity of gas is inversely proportional to its pressure as long as temperature remains constant.
Boyle's law is expressed as;
P₁V₁ = P₂V₂
Where P₁ is Initial Pressure, V₁ is Initial volume, P₂ is Final Pressure and V₂ is Final volume.
Given the data in the question
Initial volume V₁ = 2.45LInitial pressure P₁ = 1.03atmFinal pressure P₂ = 0.980 atmFinal volume V₂ = ?P₁V₁ = P₂V₂
V₂ = P₁V₁ / P₂
V₂ = ( 1.03atm × 2.45L ) / 0.980atm
V₂ = 2.5235Latm / 0.980atm
V₂ = 2.58L
Therefore, at constant temperature, if the pressure of the gas decreases to the given value, the volume increases to 2.58L.
Learn more about Boyle's law here: brainly.com/question/1437490
Correct name of the compound
Answer:
Calcium Nitride
Explanation:
Describe how alleles and genes are related.
Answer:
A gene is a stretch of DNA or RNA that determines a certain trait. Genes mutate and can take two or more alternative forms; an allele is one of these forms of a gene. Chromosomes occur in pairs so organisms have two alleles for each gene one allele in each chromosome in the pair.
If the mole fraction of sulfuric acid H2SO4 is 0.432 what is the percent by mass of H2SO4.
Answer:
19.47%
Explanation:
The percentage by mass of [tex]H_2SO_4[/tex] would be 19.47%.
The percentage by mass of a substance in solution is calculated as:
[tex]\frac{mass of substance}{mass of substance + water} * 100%[/tex]
Given that the mole fraction of [tex]H_2SO_4[/tex] = 0.432
The total number of mole fraction of a solution = 1
Hence, mole fraction of water = 1 - 0.432 = 0.568
Mass of water = molar mass x mole
= 98.079 x 0.432 = 42.37 g
Mass of [tex]H_2SO_4[/tex] = molar mass x mole
= 18.02 x 0.568 = 10.24 g
Hence,
%mass of [tex]H_2SO_4[/tex] = [tex]\frac{10.24}{10.24 + 42.37} * 100[/tex]
= 19.47%
0.450 moles of K2SO4 are dissolved in 195.0 mL of water. Calculate the molarity of the solution.
Answer:
2.31M
Explanation:
The following data were obtained from the question:
Mole of K2SO4 = 0.450 mole
Volume of water = 195.0 mL = 195/1000 = 0.195L
Molarity =...?
Molarity is defined as the mole of solute per unit litre of the solution. This can be expressed as:
Molarity = mole /Volume
With the above formula we can calculate the molarity of the K2SO4 solution as follow:
Molarity = mole /Volume
Molarity = 0.450/0.195
Molarity = 2.31M
11. Calculate the energy required to produce 12.00 mol of CI207 on the basis of the
following balanced equation.
2012(g) + 702(g) + 130 kcal yields 201207(9)
Answer: 780 kcal are required to produce 12.00 mol of [tex]Cl_2O_7[/tex]
Explanation:
Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and written along with reactants.
The balanced chemical reaction is:
[tex]2Cl_2(g)+7O_2(g)+130kcal\rightarrow 2Cl_2O_7(g)[/tex]
According to stoichiometry :
2 moles of [tex]Cl_2O_7[/tex] are produced by absorption of energy = 130 kcal
Thus 12.00 moles of [tex]Cl_2O_7[/tex] are produced by absorption of energy = [tex]\frac{130}{2}\times 12.00=780kcal[/tex]
Thus 780 kcal are required to produce 12.00 mol of [tex]Cl_2O_7[/tex]
how does the Doppler effect related to the universal expanding?
Which of these is a conversion from chemical energy to mechanical energy?
A. A dark light bulb starting to glow
B. A ball rolling down a hill
C. A person lifting a weight
D. A potato being heated in an oven
Answer:
C . A person lifting a weight
What name is given to any chemical which increase the rate of a chemical reaction
Answer:
It is called catalyst.
Answer:
A catalyst
Explanation:
is a substance that can alter the rate of a chemical reaction. Catalysts can be successfully used to increase the rate of a chemical reaction.
If the temperature of a gas decreases at constant volume which of the following would occur
Answer:
I need the things after "which of the following would occur".
Explanation:
If you were to maintain a constant volume while decreasing pressure, the temperature would also have to decrease. This is Boyle's law.
What is the wavelength of a light frequency 7.21x10^14Hz
Answer:
6.0 x 105
Explanation:
Answer:6.0 x l05
Explanation:
The strong nuclear force is always smaller than the electrostatic force true or false
Answer:
False
Explanation:
The Strong Nuclear Force is defined as an attractive force between neutrons and protons which is responsible to hold the nucleus together.
Electrostatic force is the repulsive or attractive force between two electrically charged objects.
Strong nuclear force is always greater than electrostatic force but changes with the distance. Strong nuclear attraction keeps the nucleus of an atom together in a small space as well which is stronger than their electrostatic repulsion.
it is said that, the strong nuclear force is the strongest force in the universe.
Hence, the given statement is false.
Answer:
False
Explanation:
Strong nuclear forces are much higher than the electrostatic repulsive force. In case if these strong nuclear forces would have not been there, then the nucleus would have disintegrated. This is so because only gravity cannot keep hold on these particles. The nuclear force varies with the size of nucleus. As the size of nucleus increases, the electrostatic repulsion becomes greater
Hence, the given statement is false
What was the purpose of the Apollo space missions?
to collect rock samples from Mars
to land on Saturn
to collect rock samples from the moon
to land on Jupiter
Answer:
i agree with the above to collect rock samples
Explanation:
took test got 100 best of luck
The purpose of the Apollo space missions was to to collect rock samples from the moon.
What is moon?
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of Australia).The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term and larger than all known dwarf planets of the Solar System.
It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's at 0.1654 g, with Jupiter's moon Io being the only satellite in the Solar System known to have a higher surface gravity and density.
Learn more about moon,here:
https://brainly.com/question/30653068
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Which statements correctly describe the rock cycle? Check all that apply.
Rocks are preserved through the process.
Rocks change from one type to another.
Different rock groups are interrelated.
Rocks change from one type to another in a specific order.
Environmental conditions influence a change in rock type.
Answer: I italicize for checking
Rocks are preserved through the process.Rocks change from one type to another.Different rock groups are interrelated.Rocks change from one type to another in a specific order.Environmental conditions influence a change in rock type.
Explanation:
Rocks are preserved, as in you can't destroy them completely, but no, they don't stay the same they change.
Scientific Method
PART A: Put the following steps of the scientific method in the correct order,
1 Data
2 Hypothesis
3. Conclusion
4. Problem
5. Variables
6. Research
7. Procedure
Answer:
Problem, Variables, Hypothesis, Research, Procedure, Data, Conclusion.
Explanation:
First, you have to know what the problem that you're talking about is. Then, you have to know the independent, dependent, and controlled variables are in order to make a hypothesis. Then do research about the topic. After that, you make the procedure your experiment, if that's what your doing. Then after the experiment, you find the data. Using that data, you make a conclusion.
The process by which complex compounds are broken down by enzymes and by which many organic alcohols are formed is called
Answer:
fermentation
Explanation:
Is the relationship between the amount of gas and pressure direct or indirect?
Explain your answer
Answer:
A law that states that at constant temperature, the volume of a fixed amount of a gas is inversely proportional to its pressure. A law that states that at constant temperature and pressure, the volume of a sample of gas is directly proportional to the number of moles of gas in the sample.
Explanation:
Blast furnaces extra pure iron from the Iron(IIl)oxide in iron ore in a two step sequence. In the first step, carbon and oxygen react to form carbon monoxide:
2C(s)+O2(g) arrow 2CO(g)
In the second step, iron(lll) oxide and carbon monoxide react to form Iron and carbon dioxide:
Fe203(s) + 3CO(g) arrow 2Fe(s)+ 3CO2(g)
Suppose the yield of the first step is 71.% and the yield of the second step is 72.%. Calculate the mass of oxygen required to make 7.0 kg of iron.
Be sure your answer has a unit symbol, if needed, and is rounded to 2 significant digits.
Answer:
5.9 kg
Explanation:
We must work backwards from the second step to work out the mass of oxygen.
1. Second step
Mᵣ: 55.84
Fe₂O₃ + 3CO ⟶ 2Fe + 3CO₂
m/kg: 7.0
(a) Moles of Fe
[tex]\text{Moles of FeO} = \text{7000 g Fe} \times \dfrac{\text{1 mol Fe}}{\text{55.84 g Fe}} = \text{125 mol Fe}[/tex]
(b) Moles of CO
[tex]\text{Moles of CO} = \text{125 mol Fe} \times \dfrac{\text{3 mol CO}}{\text{2 mol Fe}} = \text{188 mol CO}[/tex]
However, this is the theoretical yield.
The actual yield is 72. %.
We need more CO and Fe₂O₃ to get the theoretical yield of Fe.
(c) Percent yield
[tex]\begin{array}{rcl}\text{Percent yield} &=& \dfrac{\text{ actual yield}}{\text{ theoretical yield}} \times 100 \, \%\\\\ 72. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.72 &= &\dfrac{\text{188 mol}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{188 mol}}{0.72}\\& = & \textbf{261 mol}\\\\\end{array}[/tex]
We must use 261 mol of CO to get 7.0 kg of Fe.
2. First step
Mᵣ: 32.00
2C + O₂ ⟶ 2CO
n/mol: 261
(a) Moles of O₂
[tex]\text{Moles of O}_{2} = \text{261 mol CO} \times \dfrac{\text{1 mol O}_{2}}{\text{2 mol CO}} = \text{131 mol O}_{2}[/tex]
(b) Mass of O₂
[tex]\text{Mass of O}_{2}= \text{131 mol O }_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \text{4180 g O}_{2}[/tex]
However, this is the theoretical yield.
The actual yield is 71. %.
We need more C and O₂ to get the theoretical yield of CO.
(c) Percent yield
[tex]\begin{array}{rcl}71. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.71 &= &\dfrac{\text{4180 g}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{4180 g}}{0.71}\\\\& = & \text{5900 g}\\& = & \textbf{5.9 kg}\\\end{array}[/tex]
We need 5.9 kg of O₂ to produce 7.0 kg of Fe.
Please help I don’t understand
Which of the following is the energy that comes from changes in an atom’s nucleus?
a. thermal energy
b. nuclear energy
c. light energy
d. electrical
Which sequence represents the relationship between temperature and volume as explained by the kinetic-molecular theory?
higher temperature → more kinetic energy → more space between particles – higher volume
higher temperature → less kinetic energy → less space between particles higher volume
o higher temperature → more kinetic energy → less space between particles → lower volume
higher temperature → less kinetic energy → more space between particles lower volume
Answer:
higher temperature → less kinetic energy → less space between particles higher volume
Explanation:
