1. An atom has 57 neutrons and 42 protons. How many electrons will this atom have if it
neutral?
57
44
42
40
Answer:
42
Explanation:
Because the proton number or atomic number is equal to electron number.
Answer:
42
In order for it to be neutral there must be the same amount of protons and neutrons
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Does changing the number of protons change the identity of the element you have built ?
Answer: Yes.
Explanation:
the number of protons in the nucleus determines an element's identity. Chemical changes do not affect the nucleus, so chemical changes cannot change one type of atom into another. The number of protons in a nucleus does change sometimes, however. The identity of the atom, therefore, changes.
1. Compare and contrast the characteristics of metals and nonmetals.
2. Describe the electrochemical series and why it’s important in understanding metals.
3. Describe the theory of ionization in regard to acids and bases.
4. Identify the role of indicators.
Answer:
1. Both metals and nonmetals are types of elements and can be involved in chemical reactions. Some of their differences are highlighted in the chart below.
Metals:
Appearance; Shiny.
Conduct heat or electricity; Yes.
Malleable or ductile; Yes, both and has great mechanical strength.
Form stable compounds; Forms stable compounds with acids; also forms oxides; replaces hydrogen in acids or water; combine with nonmetals; often becomes positive.
Nonmetals :
Appearance; Not shiny .
Conduct heat or electricity; Not well .
Malleable or ductile; Brittle and not easily molded into shapes .
Form stable compounds; Oxides usually give acid reactions in water; often becomes negative
2. The electrochemical series is an arrangement of metals in such order that any metal in the list is displaced from its compounds by any metal above it, but displaces any metal below it. The higher up the list a metal is, the greater its activity. Knowing a metal’s placement on this chart can help you understand the activity of the metal, especially in regard to its ability to displace hydrogen in acids. Any items on the list far above hydrogen will do a good job at displacing it, those near it won’t do such a good job, and those below it won’t displace it from acids at all.
3. When placed in water, acids dissociate and form free hydrogen ions, which determine the properties of acids. The number of hydrogen ions determines the strength of an acid. Strong acids dissociate to a large degree and produce a large number of hydrogen ions. Weak acids dissociate to only a slight degree.
When placed in water, bases dissociate and form free hydroxyl ions, which determine the properties of bases. Strong bases dissociate to a great degree and produce a large number of hydroxyl ions. Weak bases dissociate to only a slight degree.
When free hydrogen ions and free hydroxyl ions are removed from solutions of acids and bases, then the acidic and basic properties disappear. This is what happens when acids and bases are mixed together in proper proportion; the hydroxyl ion will unite with the hydrogen ion to form water. The resulting salt product is neutral.
4. Indicators are used to help determine the pH value of an unknown solution. These are often papers that turn a certain color at certain pH values.
Metals are good conductors of heat and electricity but the non-metals are not.
Compare metals and non-metalsMetals are good conductors of electricity and heat whereas non-metals are poor conductors of heat and electricity. Metals have high density while on the other hand, non-metals have low density. Metals are malleable and ductile whereas non-metals are brittle.
So we can conclude that metals are good conductors of heat and electricity but the non-metals are not.
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Can you explain what vsepr stand for in your own word?
How many total atoms of element X are represented below?
A sealed 512 cm3 flask is full to capacity with 16 g of a substance. Determine the density of the substance.
Answer:
The answer is 0.031 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 16 g
volume = 512 cm³
We have
[tex]density = \frac{16}{512} = \frac{1}{32} \\ = 0.03125[/tex]
We have the final answer as
0.031 g/cm³Hope this helps you
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Click Oil Basics and use the information to complete this passage that discusses how plastic production affects society.
The production of plastics makes life
{answer} , so it benefits society. On the other hand, the production of plastics causes air and water {answer} , so it also harms society.
Answer:
easier and pollution
Explanation:
I just had this question and got it right
Write the principle of separation of mixture.
Explanation:
Mixtures can be separated using a variety of techniques. Chromatography involves solvent separation on a solid medium. Distillation takes advantage of differences in boiling points. Evaporation removes a liquid from a solution to leave a solid material.
Nio conducts a science experiment. He puts yeast into a bottle with water and sugar, and then caps the bottle with a balloon. He returns two hours later and notices there are bubbles on the surface of the mixture in the bottle and that the balloon has inflated, but there are no other apparent changes.
What most likely happened?
a non-chemical change, because there are no indicators of chemical changes taking place
a chemical change, because the mixture changed color
a chemical change, because a gas was produced
a non-chemical change, because the changes that occurred are reversible
Answer:the answer is a chemical change, because a gas was produced
Explanation: yeast is a chemical
Answer:
The answer is C.
"Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions."
Explanation:
Which of the following atoms has the greatest ionization energy?
a.)W
b.)C
C.)d
P.)d
Answer:
helium
Explanation:
because there are no electrons screening it from the nucleus
How do combination circuits help prevent problems in circuits in a home? If it helps, think about a bedroom since all electrical work in a bedroom is on the same circuit.
You just got a free ticket for a boat ride, and you can bring along
2 friends! Unfortunately, you have 5 friends who want to come along.
Answer:
10
Explanation:
Khan Academy
Consider the reaction below. 2 Upper N Upper H Subscript 3 (g) Baseline double headed arrow Upper N Subscript 2 (g) Baseline + 3 Upper H Subscript 2 (g). What is the most likely effect to the forward reaction if there is an increase in pressure on this reaction? The reactant surface area increases. The reaction rate decreases. The reaction is not affected at all. The reaction stops completely.
Answer:
The increase in pressure of the reacting system will increase the formation of NH₃
Explanation:
The given parameters are;
2NH₃ (g) ⇄ N₂ (g) + 3H₂ (g)
The number of molecules in the reactant side of the equation = 2 molecules
The number of molecules in the product side of the equation = 1 + 3 = 4 molecules
Avogadro's law states that equal volume of all gases at a given temperature and pressure contains equal number of molecules
Therefore, given that the number of molecules of the product are twice the number of molecules of the reactant, the volume of the product is twice the volume of the reactant
If the pressure is increased, at constant temperature by Boyles law, the volume will be reduced, favoring the formation of the low volume occupying NH₃
Therefore, the reverse reaction (formation of NH₃) will preferably occur.
Answer:
The answer is B
Explanation:
The other answer is incorrect. The correct Answer is B
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What is your carbon footprint?
the amount of carbon dioxide you use when recycling
the amount of oxygen put into the atmosphere due to your consumption of fossil fuels
the amount of carbon dioxide and oxygen in the atmosphere at any given time
the amount of carbon dioxide put into the atmosphere due to your consumption of fossil fuels
Answer:
c. .....................
Answer: the amount of carbon dioxide put into the atmosphere due to your consumption of fossil fuels
Your carbon footprint is the amount of carbon dioxide and other carbon compounds emitted, because of your use of fossil fuels.
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I need help on Chemistry?
ANYONE PLEASE?
Answer:
1. 1g/ml
Explanation:
1. Density is mass divided by volume (g/mL).
10g/10mL = 1 g/mL
2. When you already know the density and the volume, you can use the density as a unit converter.
[tex]5mL*\frac{20g}{mL} = 100g[/tex]
3. It's the same with density and mass.
[tex]20g*\frac{1mL}{5g} = 4mL[/tex]
Jamal is 8 miles away from his house. He rides his bike home toward home at a speed of 12 mph..
How far away from home is he after a half hour?
Answer: 2miles
Explanation:if he’s going 12 miles in one hour, in half an hour he would’ve made it 6 miles. 8-6=2
Answer: b. 2 miles
Explanation:
A foam square has a mass of 25 g and a volume of 90 mL. What is the density?
Answer:
The answer is 0.28 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
So we have
[tex]density = \frac{25}{90} = \frac{5}{18} \\ = 0.277777...[/tex]
We have the final answer as
0.28 g/mLHope this helps you
Each water molecule can form hydrogen bonds with up to _____ neighbors
Group of answer choices
6
8
2
4
Answer:
2
Explanation:
thats the answer.have good day
Write a balanced equation for the complete oxidation reaction that occurs when ethane burns in air
Alkanes are saturated hydrocarbons that have single bonds in chains
General formula for alkanes :
[tex]\tt \large{\bold{C_nH_{2n+2}}[/tex]
Hydrocarbon combustion reactions (specifically alkanes)
[tex]\large {\box {\bold{C_nH _ (_2_n _ + _ 2_) + \dfrac {3n + 1} {2} O_2 \Rightarrow nCO_2 + (n + 1) H_2O}}}[/tex]
So that the burning of ethane with air (oxygen):
[tex]\tt C_2H_6+\dfrac{7}{2}O_2\rightarrow 2CO_2+3H_2O[/tex]
2C₂H₆ (g) + 7O₂ (g) ⟶ 4CO₂ (g) + 6H₂O (ℓ)
or we can use mathematical equations to solve equilibrium chemical equations by giving the coefficients for each compound involved in the reaction
C₂H₆ (g) + aO₂ (g) ⟶ bCO₂ (g) + cH₂O (ℓ)
C : left 2, right b ⇒ b=2
H: left 6, right 2c⇒ 2c=6⇒ c= 3
O : left 2a, right 2b+c⇒ 2a=2b+c⇒2a=2.2+3⇒2a=7⇒a=7/2
Solve for Keq , given the following concentrations at equilibrium. Based on the calculated Keq, are products or reactants larger?
CO2 = 3.0 M O2 = 1.5 M CO = 2.0 M
Answer:
it blows up very lighty
Explanation:
What is the volume of a weather balloon that has 39 grams of helium with a density 0.017 g/mL?
Answer:
The answer is 235.29 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\ [/tex]
From the question.
density = 0.017 g/mL
mass = 4 g
We have
[tex]volume = \frac{4}{0.017} \\ = 235.2941176...[/tex]
We have the final answer as
235.29 mLHope this helps you
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Given the data below, what substance does not show a reaction for any of the tests? Hint: (+)= reaction occurred, (-)= no reaction
unknown
salt
Corn starch
Gelatin
Answer:
Salt
Explanation:
It has all -
What is the volume, in liters, of 1.40 mol of oxygen gas at 20.0°C and 0.974 atm?
Answer:
V = 34.55 L
Explanation:
Given that,
No of moles, n = 1.4
Temperature, T = 20°C = 20 + 273 = 293 K
Pressure, P = 0.974 atm
We need to find the volume of the gas. It can be calculated using Ideal gas equation which is :
PV=nRT
R is gas constant, [tex]R=0.08206\ L-atm/mol-K[/tex]
Finding for V,
[tex]V=\dfrac{nRT}{P}\\\\V=\dfrac{1.4\times 0.08206\times 293}{0.974 }\\\\V=34.55\ L[/tex]
So, the volume of the gas is 34.55 L.
Two liters of hydrogen gas are stored at a
pressure of 100 kPa. If the temperature
does not change, what will the volume
of the gas be when the pressure is
decreased to 25 kPa?
Answer:
the volume will expand
Explanation:
gas under pressure contracts, and expands with a lesser pressure
The volume of the hydrogen gas at 25 kPa is 8 Liters.
Explanation:
Given:
At constant temperature, 2 liters of hydrogen gas at 100kPa pressure.
To find:
The volume of the hydrogen gas at 25kPa.
Solution:
The initial pressure of the hydrogen gas =[tex]P_1=100 kPa[/tex]
The initial volume of the hydrogen gas at 100 kPa =[tex]V_1=2 L[/tex]
The final pressure of the hydrogen gas =[tex]P_2=25 kPa[/tex]
The final volume of the hydrogen gas at 25kPa = [tex]V_2=?[/tex]
Using Boyles law:
[tex]P_1V_1=P_2V_2\\100kPa\times 2 L=25 kPa\times V_2\\V_2=\frac{100 kPa\times 2L}{25 kPa}=8L[/tex]
The volume of the hydrogen gas at 25 kPa is 8 Liters.
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Does anybody understand this I’m stuck
Answer:
it's the first one
Explanation:
can you help me too
Calculate the density of an object with mass = 30.50 g and a volume = 2.20 cm^3
Answer:
The answer is 13.86 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass = 30.5 g
volume = 2.2 cm³
We have
[tex]density = \frac{30.5}{2.2} \\ = 13.863...[/tex]
We have the final answer as
13.86 g/cm³Hope this helps you
A metal block, 2.0cm x 2.5cm x 3.0cm, has a mass of 40.5g. What is the density of the sample? What type of metal is the metal block composed of?
Aluminum - 2.699
Copper - 8.92
Iron - 7.874
Lead - 11.43
Nickel - 8.908
Tin - 7.265
Zinc - 7.14
Answer:
The block is made up of aluminum.
density = 2.7 g/cm³
Explanation:
Given data:
Dimension of metal block = 2.0 cm×2.5 cm× 3.0 cm
Mass of block = 40.05 g
Density of block = ?
Which metal is this = ?
Solution:
Density:
Density is equal to the mass of substance divided by its volume.
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Volume of block = 2.0 cm×2.5 cm× 3.0 cm = 15 cm³
d = m/v
d = 40.5 g/ 15 cm³
d = 2.7 g/cm³
The block is made up of aluminum.
A piece of wood that measures 2.7 cm x 5.5 cm x 3.9 cm has a mass of 84 g what is the density of the wood
The density of the wood : 1.45 g/cm³
Further explanationDensity is a quantity derived from the mass and volume
Density is the ratio of mass per unit volume
With the same mass, the volume of objects that have a high density will be smaller than objects with a smaller type of density
The unit of density can be expressed in g/cm³ or kg/m³
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
Volume of the wood[tex]\tt V=2.7\times 5.5\times 3.9=57.915~cm^3[/tex]
density[tex]\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{84~g}{57.915~cm^3}=\boxed{\bold{1.45`g/cm^3}}[/tex]
which balances the equation Mg + O2 → MgO
Answer:
2Mg+[tex]O_{2}[/tex]→2MgO
Explanation:
The first step is magnesium + oxygen equals magnesium oxide
The second step is changing that into an equation which looks like Mg+[tex]O_{2}[/tex]→MgO
The third step is to 2*Mg and 2*O as well as the product has to be 2*Mg,2*O which gets the equation to become balanced as 2Mg+[tex]O_{2}[/tex]→2MgO
The coefficient 2 balance the given reaction. The balanced equation for the given reaction is given as [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].
A balanced equation is a mathematical representation of a chemical reaction that respects the law of mass conservation. It depicts the reactants and products of the reaction, as well as the relative amounts of each species. The unbalanced equation is [tex]\rm Mg + O_2 \rightarrow MgO[/tex]. One magnesium (Mg) atom on the left side and one on the right side, so the magnesium is already balanced. Balance the oxygen (O) atoms. On the left side, there are two oxygen (O) atoms present in the O2 molecule. On the right side, there is only one oxygen (O) atom in the MgO molecule. To balance the oxygen atoms, we need to add a coefficient of 2 in front of MgO: [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex]. The balanced equation is [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].
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Which statement best defines potential enregy?
A. Potential energy is stored energy.
B. Potential energy is energy that can change over time.
C.Potential energy is the energy of motion.
D. Potential energy is the type of energy a roller coaster uses.
Answer:
A. Potential energy is stored energy
Explanation:
Answer:
A
Explanation:
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