Answer:
a b d
these are part of an ecosystem or can be
Which of the following expressions is equivalent
to 7x + 9y - 6 - 3y + 4?
A 7x + 4y
B 11xy
C 7x + 6y - 2
D. 7X+4
Answer:
C
Explanation:
All that is needed to do is combine like terms. The sign in front of each term stays with it. Like +9y-3y=6y, 7x would isolate itself since it has not other term to follow. And -6+4=-2. This would all lead to C. 7x+6y-2.
The expression simplifies to 7x + 6y - 2 by combining like terms, making answer choice C the equivalent expression.
Explanation:The expression 7x + 9y - 6 - 3y + 4 can be simplified by combining like terms. First, combine the 'y' terms (9y - 3y) to get 6y. Then, combine the constant terms (-6 + 4) to get -2. After combining these terms, the expression simplifies to 7x + 6y - 2, which is answer choice C.
What do the elements in the oxygen family (Group 16) have in common?
O
A. They are all gases.
O
B. They tend not to react with other elements.
O
C. They are all nonmetals.
O
D. They tend to react in similar ways.
Answer:
D. They tend to react in similar ways.
Explanation:
A is not correct, as there is only one gas in Group 16--that being oxygen
B is not correct, as these elements actually tend to react a lot with others elements
C is not correct, as there is only three nonmetals in Group 16--those being oxygen, sulfur, and selenium
Therefore, by process of elimination, answer D. is correct
If an element has 2+ valence electrons, does it transfer only one or more than one valence electrons
Answer:
element having 2+ valence electrons can transfer its more than one electron that is 2 electron completely.
Explanation:
Group IIA have 2+ valency and two electrons in its valance shell.Its Electropositivity is high and have the tendency to donate it two electrons.Element of IIA form ionic with most electronegative element.Examples:
Cu²⁺, Mg²⁺, Sr²⁺ are examples having 2+ valance electron
one of the following is examples of element that have 2+ valence electrons
MgCl₂
Atomic number of Magnesium (Mg) is 12
Electronic Configuration of Mg:
1s², 2s², 2p⁶, 3s²
or
K =2
L = 8
M = 2
So, it have to give its 2 electrons to form a stable compound.
Similarly
Chlorine atomic number is 17
Electronic Configuration of Chlorine:
1s², 2s², 2p⁶, 3s², 3p⁵
or
K =2
L = 8
M = 7
So, it have to gain one electrons to form a stable compound and complete its octet.
So,
Two chlorine atom as a molecule gain 2 electrons from Mg²⁺ atom
So one Mg²⁺ and 2 Cl⁻ atoms form an ionic bond
where in this ionic bond Mg²⁺ transfer its 2 valence electron completely and chlorine molecule accept 2 electrons.
Cl-----Mg------Cl
So the Answer is
element having 2+ valence electrons can transfer its more than one electron that is 2 electron completely.
an inflatable toy has a volume of 310 mL. when a child takes it aboard an airliner the atmospheric pressure is 0.995 atm. as the airliner climbs,the cabin pressure drops, the toy expands to a volume of 440 mL. what is the air pressure in the airplane
Answer:
P₂ = 0.7 atm.
Explanation:
Given data;
Initial Volume = 310 mL
Initial Pressure = 0.995 atm
Final volume = 440 mL
Final pressure = ?
Solution;
P₁V₁ = P₂V₂
P₂ = P₁V₁/V₂
P₂ = 0.995 atm . 310 mL / 440 mL
P₂ = 308.45 atm. mL /440 mL
P₂ = 0.7 atm.
Answer these in order
Answer:
Explanation:
Pure Substance: are those having same type of atoms or molecules.
Compound: one or more atoms of the element combine to form a compound.
Mixture: is combination of one or more substances mix together.
Homogeneous Mixture: are those which are not distinguish by naked eye but can be separated into its components by physical means
Heterogeneous mixture: are those which can be distinguished by naked eye and can be separated into its components by physical means.
The complete detail of your answer in attachment
To whoever helps me thank you so much have a wonderful day!
Answer:
N and P
Explanation:
Anion:
When an atom gain the electrons anion is formed. The negative sign shows that atom gain electron because number of electron are greater than protons or we can say that negative charge becomes greater than positive charge.
Cation:
When atom lose electron cation is formed. The atom thus have positive charge because number of positive charge i.e protons are increased are greater than negative charge or electron.
In given problem N and phosphorus both can gain three electrons which means negative charge becomes greater that's why the extra electron gained by atoms are written as -3 and both form anion with charge -3.
while Al form cation with charge +3 Mg form cation with charge +2 and iodine and bromine both form anion with charge of -1.
2. If you had three unknowns which are starch, BaSO4, and MgO, how can you identify starch among them ?
Answer:
A chemical test for starch is to add iodine solution (yellow/brown) and look for a colour change. In the presence of starch, iodine turns a blue/black colour
Explanation:
There is a golden role of solubility, polar solute dissolve in polar solvent and non polar solute dissolve in non polar solvent. Therefore, to identify the starch solution, we need to do iodine test.
What is solution?Solutions are a homogeneous mixture of two or more substances. A solution is a homogeneous mixture of solvent and solute molecules. Solvent is a substance that is in large amount in solution. solute is the substance which is in small amount in a solution. There are two types of mixture that is homogeneous and heterogeneous. Solution is a homogeneous solution.
To know which one is starch solution amongst BaSO[tex]_4[/tex] and MgO. Add iodine solution (yellow/brown) as a chemical test for starch and watch for a color change. The color of iodine changes to a blue/black color when starch is present.
Therefore, to identify the starch solution, we need to do iodine test.
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Is the following nuclear equation balanced?
237 Np - He+233 AM
Answer:
Yes
Explanation:
Np²³⁷ → He⁴ + Am²³³
The given nuclear equation is balanced. Np²³⁷ undergoes alpha decay and produce alpha particle and Am²³³.
Properties of alpha radiation:
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number 4 less than and atomic number 2 less than the starting atom.
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy
5. Suppose the efficiency of illumination is defined as the
intensity of light absorbed by the plants divided by the
intensity of light provided to the plants. Based on the
data, would one be justified in concluding that the effi-
ciency of illumination was higher in Section 1 than in
the other sections?
A. Yes, because the illumination provided to the
plants was highest in Section 1.
B. Yes, because the amount of light not absorbed by
the plants was highest in Section 1.
C. No, because the amount of light absorbed by the
plants was lowest in Section 1.
D. No, because the information provided is insuffi-
cient to determine efficiency of illumination.
You start with 12.94 g sample of a mixture containing SiO2, NaCl, and NH4Cl. If after subliming
away the NH4Cl, you have 2.17 grams of sample remaining, what was the mass percent of NH4CI
in the original sample? Show all work.
83.23 %
Explanation:We are given;
Mass of the sample mixture is 12.94 g Mass of the remaining mixture after sublimation is 2.17 gWe are required to get the mass percent of NH₄Cl in the original sample
Step 1 : Calculate mass of NH₄Cl in the original sample;Mass of NH₄Cl = Total mass of the mixture - remaining mass after sublimation
= 12.94 g - 2.17 g
= 10.77 g
Step 2: Percent by mass of NH₄Cl in the original sample% of NH₄Cl by mass =(Mass of NH₄Cl÷Total mass of original sample)×100
= (10.77 g ÷ 12.94 g) × 100
= 83.23 %
Therefore, the percent by mass of NH₄Cl in the original sample is 83.23%
what is a hypothesis in an experiment?
i’m doing homework on independent and dependent variables in science PLEASE HELP
Answer:
A hypothesis is an educated guess.
Answer:
The hypothesis is a educated guess that you take before starting an experiment.
Explanation:
If I do blank then blank will happen. If I drink water then I won't feel thirsty. It is something that makes you take a guess about what will happen.
Part A
What is the mass of the water?
Express your answer to two significant figures and include the appropriate units.
The question focuses on calculating the mass of water using its density and volume, requiring an understanding of physics concepts and the correct application of significant figures and units.
Explanation:The question provided involves calculating the mass of water based on its density and volume, which is a fundamental concept in physics. To determine the mass of water, you use the formula mass = density × volume. The density of water is given as 1.000 ×10³ kg/m³, and various examples of volume calculations are provided, illustrating different contexts in which this calculation might be applied.
One specific calculation detailed is m = (1.000 × 10³ kg/m³) (2.00 × 10³ m³) = 1.00 × 10¸ kg, demonstrating how to apply the density-volume relationship. Another example provided is using a volume of 2.00 × 10¹ m³, resulting in a mass of 2.00 × 10±² kg. These calculations emphasize the importance of properly applying significant figures and units in physics problems.
19
An emission spectrum shows two distinct lines separated by a small gap. What does this reveal?
A)
the electron dissipated into two photons
the electron took two jumps to return to its ground state
the electron emitted two photons simultaneously during its jump
the electron underwent the transition between a higher and ground state
twice
Answer:
The electron took two jumps to return to its ground state.
Explanation:
If the electron is in nth state then it first goes to (n-1)th to 2nd state and emits one photon of this energy gap. Then, it goes to ground state and emits another photon of different energy. It can emit [tex]\left \{ {{n-1} \atop {2}} \right.[/tex] types of different photons. Fourth option is incorrect because in that case it emits one photon and absorbs one photon to go back to that state and also both photons are of same energy.
What force is necessary to accelerates a 1250kg car at a rate of 40 m/s
Answer:
F = 50000 N
Explanation:
The acceleration is rate of change of velocity of an object with respect to time.
Formula:
a = Δv/Δt
a = acceleration
Δv = change in velocity
Δt = change in time
Units:
The unit of acceleration is m.s⁻².
Acceleration can also be determine through following formula,
F = m × a
a = F/m
Given data:
Mass of car = 1250 Kg
Acceleration = 40 m/s².
Force = ?
Solution:
F = m × a
F = 1250 Kg × 40 m/s²
Kg.m/s² = N
F = 50000 N
Based on Dalton's atomic theory, what do atoms consist of?
Compounds
Elements
Molecules
Particles
Answer:
Your answer would be particles
Explanation:
The atom consist of subatomic particles like electrons protons and neutrons.
Convert 325 milliliters to liters.
A:0.325 liters
B:3.25 liters
C:32.5 liters
D:325 liters
Answer:
The Awnser Is A. 0.325 Liters
Explanation:
The temperature of a 268 mL sample of gas increases from 151. K to 353. K. What is the final volume of the sample of gas, if the pressure in the container is kept constant?
Answer:
V₂ = 626.52 mL
Explanation:
Given data:
Initial volume = 268 mL
Initial temperature = 151 K
Final temperature = 353 K
Final volume = ?
Solution:
V₁ / T₁ = V₂ / T₂
V₂ = V₁ T₂/ T₁
V₂ = 268 mL× 353 K / 151 K
V₂ = 94604 mL.K / 151 K
V₂ = 626.52 mL
Please help me! I am offering 100 points and brainliest!
Write a few sentences summarizing how density is changed by changing the mass without changing the volume and by changing the volume of a substance without changing the mass (both by increasing and decreasing). If you prefer, you can use specific numbers and calculations to show the relationship instead.
Explanation:
Since density is calculated with mass divided by volume, changing either of these variables will affect the density, not necessarily both of them. If only the volume is increased or only the mass is decreased, the density will decrease. If only the volume is decreased or only the mass in increased, the density will increase.
Example:
Original density is 50g/ml. Mass is 50g and volume is 1ml.
Increase mass only:
mass = 100g
Density = 100g/ml <= Density is increased
Decrease mass only:
mass = 25g
Density = 25g/ml <= Density is decreased
Increase volume only:
volume = 2ml
Density = 50g/2ml = 25g/ml <= Density is decreased
Decrease volume:
volume = 0.5ml
Density = 50g/0.5ml = 100g/ml <= Density is increased
A gas that exerts a pressure of 14 bar
in a container with a volume of 312 mL will exert a pressure of ______bar when transferred to a container with a volume of 652 mL.
Assume that the number of moles and the temperature remain constant.
Answer:
A gas that exerts a pressure of 14 bar in a container with a volume of 312 mL will exert a pressure of 6.7 bar when transferred to a container with a volume of 652 mL.
Explanation:
Given data;
Initial pressure = 14 bar
Initial volume = 312 mL
Final pressure = ?
Final volume = 652 mL
Solution:
P₁V₁ = P₂V₂
P₂ = P₁V₁ / V₂
P₂ = 14 bar 312 mL / 652 mL
P₂ = 4368 bar. mL /652 mL
P₂ = 6.7 bar
A gas that exerts a pressure of 14 bar in a container with a volume of 312 mL will exert a pressure of 6.7 bar when transferred to a container with a volume of 652 mL.
Answer:
P₁V₁ = P₂V₂
P₂ = P₁V₁ / V₂
P₂ = 14 bar 312 mL / 652 mL
P₂ = 4368 bar. mL /652 mL
P₂ = 6.7 bar
A gas that exerts a pressure of 14 bar in a container with a volume of 312 mL will exert a pressure of 6.7 bar when transferred to a container with a volume of 652 mL.
Explanation:
Which of the following are lost or gained during a nuclear reaction? (5 points)
a Electrons and nucleus
b Electrons and neutrons
c Protons and electrons
d Protons and neutrons
D
Nuclear reaction involves the nuclei of atoms. The nucleus can either split (as is the case with fission) of fuse as is the case with nuclear fusion. Remember the main particles in the nucleus are protons and neutrons.
Explanation:
In nuclear fission, atomic nuclei split into lighter atoms through loss of protons and neutrons (such as through loos of a beta particles - 2 protons and 2 neutrons). In the case of fusion, two atomic nuclei fuse under pressure (hence adding neutrons and protons) to create heavier atoms (2 hydrogens can fuse to form a helium). Electrons are not involved in nuclear reactions. Electrons are mainly involved in chemical reactions.
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Write the reaction rate expressions for the
following reactions?
2H2+O2_____2H2O
Answer:
see attachment
Explanation:
1. A dining hall had a total of 25 tables-some long rectangular tables and some round
ones. Long tables can seat 8 people. Round tables can seat 6 people. On a busy
evening, all 190 seats at the tables are occupied.
How many long tables, x, and how many round tables, y, are there?
x = 20 long tables
y = 5 round table
Explanation:
We have the following system of equations:
x + y = 25
8x + 6y = 190
From the first equation we have:
x = 25 - y
And we replace x in the second equation:
8(25 - y) + 6y = 190
200 - 8y + 6y = 190
200 - 2y = 190
200 - 190 = 2y
10 = 2y
y = 5
Now we insert the value of y in the next equation:
x = 25 - y
x = 25 - 5
x = 20
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Given the total number of tables and the number of seats they provide, we can derive a system of linear equations to solve for the number of each type of table.
Explanation:This is a problem of linear algebra. Given that the total number of tables is 25 and each type of table seats a different number of people, we can set up the following system of equations:
Equation 1): x + y = 25 (This equation comes from the fact that there are 25 tables total, a sum of long rectangular tables, x, and round tables, y.)
Equation 2): 8x + 6y = 190 (This equation comes from the fact that all the seats at the tables are occupied and we know how many people each type of table can seat.) Solving these equations simultaneously will give us the values of x and y. This type of problem is common in Systems of Linear Equations in algebra.
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The rate of reaction for a hypothetical reaction was found to be 0.62 mol/L*s at 6°C. What would be the rate at 46°C?
Answer:
9.92 mol/L*s
Explanation:
Given data:
Rate of reaction = 0.62 mol/L*s
Temperature = 6°C
Rate of reaction at 46°C = ?
Solution:
There are 10 increase in four time of given temperature.
6+10 = 16
16+ 10 = 26
26+10 = 36
36=10 = 46
According to thumb rule,
By doubling the reaction four time the rate will be,
0.62 mol/L*s ×2⁴
0.62 mol/L*s × 16
9.92 mol/L*s
A chocolate brownie had a volume of 640 cm³ and a mass of 480 g. Calculate its density!
Answer:
The density is : 0,75 g/cm3
Explanation:
We use the formula
density= mass/volume = 480 g/ 640cm3= 0, 75 g/cm3
chemical formula for iron (l) selenide
Answer:
Iron can not form iron(i) selenide however it can form iron(ii) selenide.
Explanation:
The possible oxidation states of iron are +2 and +3.
Iron can form iron (ii) selenide.
The formula of iron (ii) selenide is FeSe.
In iron (ii) selenide the oxidation state of iron is +2.
The ratio of both atoms are 1:1.
Its molecular weight is 134.82 g/mol.
It is toxic compound.
Its melting point is 965°C.
Its density is 4.72 g/cm³.
Iron can also form iron (iii) selenide.
The formula of iron (iii) selenide is Fe₂Se₃.
In iron (iii) selenide the oxidation state of iron is +3.
The ration of both atoms are 2:3.
It also known as ferric selenide.
Its molecular weight is 348.57 g/mol.
How many moles are there in 50.5 atoms ba
8.386 × 10^-23 moles
Explanation:We are given;
Number of atoms of Ba is 50.5 atomsWe are required to determine the number of moles
We need to know that 1 mole of an element contains atoms equivalent to the Avogadro's number, 6.022 × 10^23.Therefore, 1 mole of an element contains 6.022 × 10^23 atomsIn this case;
1 mole of Ba contains 6.022 × 10^23 atoms
Number of moles = 50.5 atoms ÷ 6.022 × 10^23 atoms
= 8.386 × 10^-23 moles
The number of moles in 50.5 atoms of Ba is 8.386 × 10^-23 moles
Math
Science
Social studies
They are different subjects
In science we study physical , chemical and biological things
In maths we study about data handling, algorithms etc
In social we study about political economical and historical things
Answer:
hey are different subjects
In science we study physical , chemical and biological things
In maths we study about data handling, algorithms etc
In social we study about political economical and historical things
Explanation:
what is the easiest way to separate hydrogen and oxygen out of a water molecule?
A.) Boil the water until the chemical bonds break
B.) They cannot be separated by using physical properties
C.) Filter the water using charcoal to break the chemical bonds
D.) Use a magnet to pull out the metallic bonds
A red blood cell placed in distilled water will swell due to the diffusion of
Answer:
Osmosis
Explanation:
Particle in water move from low concentration to higher concentration in semi-permeable membrane. The particle of water would be less concentrated therefore the water would move into red blood cell therefore building in mass due to water and therefore swelling
Name a method that could be used to separate magnesium hydroxide from sea water
Answer:
Add limewater
Explanation:
Ca(OH)₂ is about 1000 times more soluble than Mg(OH)₂
If you add limewater to the seawater, the magnesium ions will precipitate out as magnesium hydroxide.
Mg²⁺(aq) + 2OH⁻(aq) ⟶ Mg(OH)₂(s)