PLEASE HELP!!!!
7. According to Mohs Hardness scale, which of these groups of minerals can scratch fluorite? А. B. talc, calcite, and apatite calcite, quartz, and topaz apatite, orthoclase, and corundum diamond, gypsum, and quartz C.
Answer:
B
IS THE CORRECT ANSWER
The
the surface area of the reactants, the faster the reaction rate.
A. greater
B. lesser
0.45 g of hydrated sodium carbonate crystals were heated until 3.87 of anhydrous power remained.
How many moles of water are there in one mole of hydrated salt?
Formula of hydrated sodium carbonate : Na₂CO₃.10H₂O, so moles of water in one mole of hydrated salt = 10
Further explanationHydrate is a compound that binds water (H₂O), usually in the form of crystals/ solids
If these compounds are dissolved in water or heated, the hydrates can decompose:
Example: X.YH₂O (s) → X (aq) + YH₂O (l)
The formula for the hydrated compound contains: YH2O
The mole ratio shows the ratio of the coefficients of the hydrate compound
10.45 hydrated sodium carbonate(Na₂CO₃.xH₂O) were heated until 3.87 of 3.87of anhydrous (Na₂CO₃) remained, so
mass H₂O released :
[tex]\tt 10.45-3.87=6.58~g[/tex]
mass Na₂CO₃ = 3.87 g
mol ratio Na₂CO₃(MW= g/mol) : H₂O(MW=18 g/mol) =
[tex]\tt \dfrac{3.87}{105,9888}\div \dfrac{6.58}{18}=0.0365\div 0.3655=1\div 10[/tex]
What is the total number of electrons in an atom of an element with an atomic number of 18 and a mass number
of 40?
a. 58
c. 22
b. 18
d. 40
Answer:
18
Explanation:
In neutral atom protons and electrons are equal in number as it atomic number or proton number is 18 so electrons are also 18
The total number of electrons in an atom of an element with an atomic number of 18 and a mass number of 40 is 18.
What are the difference between atomic number and atomic mass ?Atomic mass can be defined as the total number of neutrons and protons located in nucleus of an element while atomic number is the number of protons present in the nucleus of element.
Atomic mass can be defined as the average weight of an element where as the atomic number is the total number of protons present in the nucleus; Atomic mass have the symbol A while atomic number have the symbol the letter Z.
Different isotopes of an element are differentiated by atomic mass is while isotopes share the same atomic number, in neutral atom protons and electrons are equal to atomic number or proton number is 18 and electrons are also 18
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Which sentence best explains the relationship between pressure and the
solubility of a gas?
A. The greater the pressure, the more gas that will dissolve.
B. Solubility increases with pressure for some gases but not others.
C. The lower the pressure, the more gas that will dissolve.
D. Pressure has no effect on the solubility of gases.
Answer: A. The greater the pressure, the more of gas that will dissolve.
Explanation: Increasing pressure increases the solubility of gases. It has little effect on the solubility of liquids and solids.
Question:
In a laboratory demonstration, a balloon filled with methane and oxygen was exposed to a
flame. The result was a brief, large flame. The students were asked to formulate an equation for
the reaction. One answer is below.
CH, + 0 = CO,
This equation is incorrect.
A. Explain how and why it is incorrect
B. What would the correct equation be, and how do you know that?
Answer:
The laboratory demonstration consists of the following;
The compounds present in the combustion reaction = Methane, CH₄ and Oxygen, O₂
The chemical equation for the combustion reaction is given as follows;
CH₄ + 2O₂ → CO₂ + 2H₂O
Therefore;
A. The equation given as CH₄ + O → CO₂ is not correct because;
1) Oxygen gas exist as diatomic molecules, O₂, and given that the experiment involves the mixture of gases, the oxygen gas present which can exist as a separate compound, should be represented as O₂
2) The number of oxygen molecules in the reaction is two rather than one
3) The product also includes two molecules of water (vapor) H₂O
B. The correct equation for the reaction should be given as follows;
CH₄ + 2O₂ → CO₂ + 2H₂O
B i) The constituents of the equation is obtained by the knowledge of the fact that the combustion reaction of an organic substance such as methane in the presence of oxygen yields, carbon dioxide and water (vapor)
The equation showing the relative amounts the reacting compounds is by balancing the basic equation of the combustion of methane in the presence of oxygen
Explanation:
By examining the diagram, which of the following is NOT needed for photosynthesis:
O sunlight
O carbon dioxide
O water
oxygen
Electric circuit are a pathway for ____ to flow
A.) Neutrons
B.) Protons
C.) Matter
D.) Electrons
Answer:
Electrons
Explanation:
The source that gives the voltage (force) causes the electrons to move.
Answer:
The answer is Electron
Explanation:
Does anyone know how to determine if a reaction is a redox or not?
2Ca+O2→2CaO2 is the reaction. I've already made it a balanced equation, I just need to determine if its a redox or not.
Thank you!
The reaction is included in a redox reaction
Further explanation:
Given
Reaction
2 Ca + O₂ → 2 CaO
Required
a redox reaction
Solution
Redox reactions are reactions where there is a change in oxidation number
Oxidation is an increase/increase in oxidation number, while reduction is a decrease/decrease in oxidation number.
Reducing agents are substances that experience oxidation and oxidizing agent are substances that experience reduction
in the above reaction is included in a redox reaction because there is a change in oxidation number
Ca⇒Ca²⁺+ 2e⁻(for balanced equation : 2Ca⇒2Ca²⁺+4e⁻)
Oxidation ( 0 to +2)
O₂+2e⁻⇒O²⁻(for balanced equation : O₂+4e⁻⇒2O²⁻)
Reduction (0 to -2)
in which of the following is the symbol for the ion and the number of electrons it contains given correctly? *
Answer:Number of electrons that are present in an atom is determined by the electronic configuration of that atom.
If an ion is carrying a positive charge, it means that the atom has lost electrons and if an ion is carrying a negative charge, it means that the atom has gained electrons.
For the given options:
Option A: The atomic number of hydrogen atom is 1 and the electronic configuration for ion will be:
Thus, this atom does not have any electrons.
Option B: The atomic number of bromine atom is 35 and the electronic configuration for ion will be:
Thus, this atom has 36 electrons.
Option C: The atomic number of aluminium atom is 13 and the electronic configuration for ion will be:
Explanation:
Which is the formula for iodine tribromide?
IBr
IB3
IBr3
I3Br
Answer:
the answer is c IBr3
Explanation:
The chemical formula for iodine tribromide is IBr₃ as it has 1 iodine and 3 bromine atoms.
What is chemical formula?
Chemical formula is a way of representing the number of atoms present in a compound or molecule.It is written with the help of symbols of elements. It also makes use of brackets and subscripts.
Subscripts are used to denote number of atoms of each element and brackets indicate presence of group of atoms. Chemical formula does not contain words. Chemical formula in the simplest form is called empirical formula.
It is not the same as structural formula and does not have any information regarding structure.It does not provide any information regarding structure of molecule as obtained in structural formula.
There are four types of chemical formula:
1)empirical formula
2) structural formula
3)condensed formula
4)molecular formula
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How many liters will 90.0 grams of xenon gas (Xe) occupy at STP?
HELP PLEASE
Answer:
22.4L
Explanation:
not sure if its totally correct but I tried
How much work is required to pull a sled if you use 60J of work in 5 seconds?
Answer:
DO I Look Like santa too you how am i supposed to know How about this how about you goo.gle the answer wow smart
Explanation:
If a metal donates or loses an electron it becomes a..
A. Ionic
B. Covalent
C. Metallic
Answer:
c
Explanation:
Answer:
the answer to your question is c
Which model best represents a pattern?
Antenne UHF
Chaum
RTG
Master
Antenne
grand gain
DAN
REMS
RAD
SAM
Chemin
Question 14
An element's periodic table identity is defined by its number of
А.
neutrons.
B
isotopes.
С C
electrons.
protons
Answer:
c
Explanation:
protons are the atomic number which define an element
Hair is composed of a protein called cellulose
O
True
O False
Answer:True
Explanation:
Iv done this before
What is atomic mass made of?
Answer:
Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.
Explanation:
How many moles of water are produced when 5 moles of hydrogen gas react with 2 moles of oxygen gas?
Balanced equation: 2H2 + O2 → 2H2O (5 points)
a. 2 moles of water
b. 4 moles of water
c. 5 moles of water
d. 7 moles of water
Answer:
It is b
Explanation: I did it on the test and got it right
The moles of water are produced when 5 moles of hydrogen gas react with 2 moles of oxygen gas - b. 4 moles of water
The stoichiometric coefficients can be considered in a balanced equation as moles of reactants needed or moles of products formed in the reaction.
In the given case, the balanced chemical equation for this synthesis reaction looks like this2H2 + O2 → 2H2O
from the balanced equation, it is clear that the 2 moles of hydrogen gas and 1 mole of oxygen gas are required to produce 2 moles of water. so it means that the reaction produces twice as many moles of water as you have moles of oxygen gas that take part in the reaction and the same moles as hydrogen atoms present.Here it is given that there are only 2 moles of oxygen which means it is in deficiency however, it will produce 4 moles of water with four moles of hydrogen.Thus, the moles of water are produced when 5 moles of hydrogen gas react with 2 moles of oxygen gas - b. 4 moles of water
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5. The compound is called:
*
(1 Point)
VP2
Vanadium (1) phosphide
Vanadium (IV) phosphide
Vanadium phosphide
Vanadium (VI) phosphide
Vanadium (V) phosphide
6. The compound is called
Answer:
Vanadium (VI) Phosphide
Explanation:
Vanadium has a 6+ charge for this compound, so there needs to be two phosphorus atoms to satisfy the charges. This is an ionic compound as well so the roman numerals need to be present.
When an ionic bond forms what type of ions are joined?
where information about each element is located
Answer:
On the pereiodic table.
Explanation:
All of the alkaline earth metals are similar in that – they are all artificially made elements they all have similar atomic weights. they all have the same ionic charge. they all show variable valences.
Answer:
they all have the same ionic charge.
Explanation:
Alkaline earth metals are group 2 metals on the periodic table. They are divalent elements because they have two valence electrons and ionize by donating these two valence electrons. Elements in this group have the same numbers of electrons in their outermost shell of their atoms. i.e. they all have the same number of valence electrons and ionic charge.
A beaker containing 6.32 moles of PBr3, contains___
molecules of PBrz.
A) 1712.7
B) 3.1 x 10^24
C) 3.8 x 10^24
D) 271
Answer:
3.8 x 10²⁴molecules
Explanation:
Given parameters:
Number of moles = 6.32moles
Unknown:
Number of molecules = ?
Solution:
The number of moles can be used to derive the number of molecules found within a substance.
Now,
1 mole of substance contains 6.02 x 10²³ molecules
6.32 mole of PBr₃ will contain 6.32 x 6.02 x 10²³ = 3.8 x 10²⁴molecules
What is the affected variable in an experiment. A:independent. B:dependent. C:control
In a controlled experiment, an independent variable (the cause) is systematically manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled. The researcher can operationalize (i.e. define) the variables being studied so they can be objectivity measured.
IamSugarBee
In a lever,E×E.D.=L×__________
Answer:
LD is a answer okkkkkkkkkkkkkkkkk
Most of the elements on the Periodic Table are metals.
True
False
Answer:
the answer is true
Explanation:
I hope so it is helpful to u
Which best explains the difference between a monomer and a polymer?
A monomer is larger than a polymer.
A monomer contains carbon and a polymer does not.
A polymer contains carbon and a monomer does not.
A polymer is larger than a monomer.
The difference between the monomer and a polymer should be that monomer should be larger than a polymer.
Difference of monomer and a polymer?The monomer represent the molecule type where it has the capability for chemically the bond along with the other molecules with respect to the long chain. While the polymer should represent the chain of the non-specified the no of monomers.
Also, it represent the building blocks of polymers that contain more complex type of molecules
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Answer:
A
Explanation:
A group of tourists were on an outing when they noticed that precipitation began to fall. The air temperature was 32 degree Fahrenheit. What type of precipitation did they most likely see?
Answer:
The correct answer is - rain.
Explanation:
At 32 degrees c or zero degrees Celsius, droplets of water in the atmosphere do not freeze as it is not the temperature at which water freezes but it is the temperature at which ice melts.
At this temperature the water changes its state, below 32 degrees Fahrenheit the water freezes but in the atmosphere, it not freezes necessarily and remains in the liquid state and called super-cooled liquid or water. Above this temperature, water in liquid state.
Thus, the precipitation is in the form of rain.
Please answer these. The tables needed for question 7 are in the picture. I got rid of some of the questions that you wouldn’t be able to answer without doing the lesson
Question 1: Electron Notation Example (2 points)
a. Give the electron configuration of vanadium (V), atomic number 23. (0.5 points)
b. Give the noble gas configuration of vanadium (V), atomic number 23. (0.5 points)
c. List the energy levels for the orbital configuration of vanadium (V), atomic number 23. (1 point)
Question 3: Trends on the Periodic Table (2 points)
a. How does the atomic radius change going down and across the periodic table? (0.5 points)
b. How does first ionization energy change going down and across the periodic table? (0.5 points)
c. How does electronegativity change going down and across the periodic table? (0.5 points)
d. How does the radius of a positive and negative ion compare to a neutral atom? (0.5 points)
Question 4: Chemical Bonds (1 point)
Match each chemical bond to its correct description. (1 point)
A. Ionic bond ___ Sharing of electrons
B. Covalent bond ___ Freely moving electrons
C. Metallic bond ___ Transfer of electrons
Question 5: Intermolecular Forces (3 points)
a. Describe the dipole-dipole force. (1 point)
b. Describe hydrogen bonding. (1 point)
c. Describe the Van der Waals forces. (1 point)
Question 6: Intermolecular Forces and You (2 points)
Imagine you need to take a medicine that the doctor has prescribed for you. Explain why scientists who developed that medicine would need to know whether or not the compound in that medicine is polar. How might a polar medicine behave differently within your body than a nonpolar medicine would? Answer in 1 to 2 paragraphs.
Question 7: Energy in Bonds (9 points)
Use these tables for reference for all parts of this question.
This table summarizes the average energies of single bonds between atom pairs in many different compounds.
a. According to Table 2, which is the strongest bond? Which is the weakest bond? Based on what you know about the atomic radii and electronegativity of the elements involved in the bonds, why do you think these two have the most extreme bond-energy values? (3 points)
b. How are the bond energies of each bond listed in Table 2 determined? (1 point)
c. Why do you think there aren't bond energy values given in Table 2 for N–S and S–I? (1 point)
d. Based on Tables 1 and 2, how would you describe the trend in bond strength of single, double, and triple bonds? (1 point)
e. Based on Table 2, how would you describe the trend in the strength of bonds formed by the elements carbon, nitrogen, and oxygen? Would you describe this trend as a periodic trend? Why or why not? (3 points)
Question 8: Causes of Molecular Shape (3 points)
a. What is the VSEPR theory? (1 point)
b. How does electron repulsion determine molecular shape? (1 point)
c. How do lone electron pairs affect molecular shape? (1 point)
Question 10: Lewis Structure (3 points)
a. Draw the Lewis structure for the Se and 2 H atoms. (1 point)
b. Draw the Lewis structure for the SeH2 molecule. (1 point)
c. What shape would SeH2 have? Draw the molecule. (1 point)
Question 11: Ionic and Covalent Compounds (5 points)
Identify each of the following as a covalent compound or ionic compound. Then provide either the formula for compounds identified by name or the name for those identified by formula. (1 point each)
a. Li2O:
b. Dinitrogen trioxide:
c. PCl3:
d. Manganese(III) oxide:
e. Calcium bromide:
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Therefore, the electronic configuration of vanadium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d³.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
The systematic distribution of electrons in the various atomic orbitals is called its electronic configuration. The atomic number of vanadium is 23. The electronic configuration of vanadium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d³. The noble gas electronic configuration of vanadium is [Ar]3d³4s². 1,2,3 represents the number of shells and s and represents the orbitals. The superscripts represents the number of electrons in each orbitals.
Therefore, the electronic configuration of vanadium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d³.
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