Answer:
Fossils tell us when organisms lived, as well as provide evidence for the Fossils are the preserved remains or traces of animals, plants, and other organisms from the past. Fossils, by comparing the anatomies of both modern and extinct species, allows scientists to study the skin, hair, and organs of ancient creatures.
Explanation:
Decide whether a chemical reaction happens in either of the following situations. If a reaction does happen, write the chemical equation for it. Be sure your chemical equation is balanced and has physical state symbols. situation chemical reaction.
A strip of solid tin metal is put into a beaker of 0.074M MgBr2 solution .
Answer:
Sn(s) + MgBr2(aq) --> SnBr2(aq) + Mg(s)
Explanation:
Decide whether a chemical reaction happens in either of the following situations.
- A reaction happens. The type of this reaction is the single replacement reaction.
If a reaction does happen, write the chemical equation for it.
Sn(s) + MgBr2(aq) --> SnBr2(aq) + Mg(s)
How can weak acids and weak bases cause pH stress to cells?
a. Weak bases will only cause pH stress at low pH.
b. If a cell has transporters that are not well regulated, weak acids or weak bases can accumulate inside the cells and cause stress.
c. Only weak acids can cause stress by diffusing across a membrane at low pH.
d. At certain pH levels, both weak acids or weak bases will be uncharged, and thus are small uncharged molecules that can diffuse across a membrane and cause pH stress inside the cell. e. Weak acids and weak bases do not cause stress.
Answer:
b
Explanation:
If a cell has transporters that are not well regulated, weak acids or weak bases can accumulate inside the cells and cause stress.
Why does there appear to be another duck head in the water?
A
The water in the pond reflects light from the Sun, making a mirror image
B
The molecules in the atmosphere refract the light, splitting it into two ima
С
The duck scatters the light, making hundreds of tiny refractions that collec
D
The bottom of the pond absorbs the light, then projects it toward the surfa
Answer:
it's A. The water in the pond reflects light from the Sun, making a mirror image
Explanation:
i just took the test
Can someone help me with these two?
Answer:
adding
opposite
Explanation:
dont blame me if u get them wrong
Answer:
first one is adding i belive and second one is opposite
Explanation:
Why does Hydrogen not belong to any group?
Answer: Hydrogen is not in any group because it only has on electron
Explanation:
5.6 g of an organic compound on burning with excess
of oxygen gave 17.6 g of CO2, and 7.2 g of H,O. The
organic compound is :
Answer:organic compound is : C₄H₈
Explanation: The equation of the reaction of the organic compound burning with excess oxygen gives us the general equation as
C xHy + 1/2(x+ y/2 )O₂ → xCO₂ + y/2H₂O
We first find the number of moles of CO₂ and H₂O
Number of moles of CO₂= Mass/ molar mass
= 17.6g/ 44g/mol ( 12+ 16 x2)
=0.4 moles
Number of moles of H₂O= Mass/ molar mass
= 7.2g/ 18g/mol ( 1 X 2+ 16)
=0.4 moles
From the reaction , we can see that
x = 0.4
and [tex]\frac{y}{2}[/tex]= 0.4 such that y= 0.4 x 2= 0.8
Their ratios become
[tex]\frac{x}{y}[/tex] =[tex]\frac{0.4}{0.8}[/tex]= [tex]\frac{4}{8}[/tex]
Therefor the organic compound CxHy = C₄H₈
What mass of KNO, will dissolve in 100 g of water at 100°C?
Answer:
About 170-180 grams of potassium nitrate are completely dissolved in 100 g.
Explanation:
Hello!
In this case, according to the reported solubility data for potassium nitrate at different temperatures on the attached picture, it is possible to bear out that about 170-180 grams of potassium nitrate are completely dissolved in 100 g; considering that the solubility is the maximum amount of a solute that can be dissolved in a solvent, in this case water.
Best regards!
1. Fill in the blanks. Example: A nitrogen atom takes on a 3- charge when it forms an anion and becomes nitride. a. A magnesium atom takes on a ___ charge when it forms a(an) ____ion and becomes . b. A chlorine atom takes on a ___ charge when it forms a(an) ____ion and becomes . c. An oxygen atom takes on a ___ charge when it forms a(an) ____ion and becomes . d. A potassium atom takes on a ___ charge when it forms a(an) ____ion and becomes .
Answer: a. +2, cation and magnesium ion .
b. -1, anion, chloride
c. -2, anion, oxide
d. +1. cation , potassium ion
Explanation:
When an atom accepts an electron negative charge is created on atom and is called as anion.
When atom loses an electron positive charge is created on atom and is called as cation.
Magnesium (Mg) with atomic number of 12 has electronic configuration of 2,8,2 and thus it can lose 2 electrons to form [tex]Mg^{2+}[/tex] cation and becomes magnesium ion.
Chlorine (Cl) with atomic number of 17 has electronic configuration of 2,8,7 and thus it can gain 1 electron to form [tex]Cl^{-}[/tex] anion and becomes chloride.
Oxygen (O) with atomic number of 8 has electronic configuration of 2,6 and thus it can gain 2 electrons to form [tex]O^{2-}[/tex] anion and becomes oxide.
Potassium (K) with atomic number of 19 has electronic configuration of 2,8,8,1 and thus it can lose 1 electron to form [tex]K^{+}[/tex] cation and becomes potassium ion.
A: A 21.3−g sample of dinitrogen monoxide is confined in a 5.76−L vessel. What is the pressure (in atm) at 111°C?
B: Find the density of Freon−11 (CFCl3) at 157°C and 4.65 atm.
g/L = ?
Answer:
A. 2.65 atm.
B. 18.11 g/L.
Explanation:
A. Determination of the pressure
Mass of N₂O = 21.3 g
Volume = 5.76 L
Temperature (T) = 111 °C
Pressure (P) =.?
First, we shall determine the number of mole in 21.3 g of dinitrogen monoxide, N₂O. This can be obtained as follow:
Mass of N₂O = 21.3 g
Molar mass of N₂O = (14×2) + 16
= 28 + 16
= 44 g/mol
Mole of N₂O =?
Mole = mass /Molar mass
Mole of N₂O = 21.3/44
Mole of N₂O = 0.484 mole
Next, we shall convert 111°C to Kelvin temperature. This can be obtained as follow:
T(K) = T(°C) + 273
Temperature (T) = 111 °C
Temperature (T) = 111 °C + 273
Temperature (T) = 384 K
Finally, we shall determine the pressure. This can be obtained as follow:
Number mole of N₂O = 0.484 mole
Volume = 5.76 L
Temperature (T) = 384 K
Gas constant (R) = 0.0821 atm.L/Kmol
Pressure (P) =.?
PV = nRT
P × 5.76 = 0.484 × 0.0821 × 384
Divide both side by 5.76
P = (0.484 × 0.0821 × 384) / 5.76
P = 2.65 atm
B. Determination of the density of CFCl₃
Temperature (T) = 157°C
Pressure (P) = 4.65 atm.
Density of CFCl₃ =?
First, we shall determine the molar mass of CFCl₃. This can be obtained as follow:
Molar mass of CFCl₃ = 12 + 19 + (35.5×3)
= 12 + 19 + 106.5
= 137.5 g/mol
Next, we shall convert 157°C to Kelvin temperature. This can be obtained as follow:
T(K) = T(°C) + 273
Temperature (T) = 157 °C
Temperature (T) = 157 °C + 273
Temperature (T) = 430 K
Finally, we shall determine the density of CFCl₃. This can be obtained as follow:
Temperature (T) = 430 K
Pressure (P) = 4.65 atm.
Molar mass of CFCl₃ (M) = 137.5 g/mol
Gas constant (R) = 0.0821 atm.L/Kmol
Density (D) of CFCl₃ =?
D = PM / RT
D = (4.65 × 137.5) / (0.0821 × 430)
D = 18.11 g/L
Suppose that X represents an arbitrary cation and that Y represents an anionic species. Using the charges indicated in the superscript of X and Y, fill in the remaining blanks below by writing the appropriate subscript for each X and Y to balance the net charge on the ionic XaYb compound formed (where a and b represent positive, whole numbers of X and Y, respectively).
Y- Y2- Y3-
X+
X2+ XY2
X3+
Answer:
See explanation.
Explanation:
Hello!
In this case, when having the cationic and anionic species with the specified charges, in order to abide by the net charge rule, we need to exchange the charges in the form of subscripts and without the sign, just as shown below:[tex]X^{m+}Y^{n-}\rightarrow X_nY_m[/tex]
Thus, for all the given combinations, we obtain:
- Y⁻
[tex]X^+Y^-\rightarrow XY\\\\X^{2+}Y^-\rightarrow XY_2\\\\X^{3+}Y^-\rightarrow XY_3[/tex]
- Y²⁻
[tex]X^+Y^{2-}\rightarrow X_2Y\\\\X^{2+}Y^{2-}\rightarrow X_2Y_2\rightarrow XY\\\\X^{3+}Y^{2-}\rightarrow X_2Y_3[/tex]
- Y³⁻
[tex]X^+Y^{3-}\rightarrow X_3Y\\\\X^{2+}Y^{3-}\rightarrow X_3Y_2 \\\\X^{3+}Y^{3-}\rightarrow X_3Y_3\rightarrow XY[/tex]
Best regards!
A sample of a compound was found that has 40.25g of (C) Carbon and 59.75g of (O) Oxygen.
What is the empirical formula for this sample.
Answer:
CO
Explanation:
From the question given above, the following data were obtained:
Mass of Carbon (C) = 40.25 g
Mass of oxygen (O) = 59.75 g
Empirical formula =?
The empirical formula of the compound can be obtained as follow:
C = 40.25 g
O = 59.75 g
Divide by their molar mass
C = 40.25 / 12 = 3.354
O = 59.75 / 16 = 3.734
Divide by the smallest
C = 3.354 / 3.354 = 1
O = 3.734 / 3.354 = 1
The empirical formula of the compound is CO
In the benzene molecule, carbon atoms form a ring with alternating single and double bonds in between each of them. Each carbon atom forms one σ bond with one carbon atom and one σ and one π bond with another. The π bonding electrons are delocalized over the entire molecule. Thus, benzene is a resonance hybrid of two equivalent structures, and the single and double bonds oscillate from one position to the other.
Required:
Calculate the bond order for one carbon-carbon bond in the benzene molecule, taking σ and π bonding into consideration.
Answer:
1.5
Explanation:
From;
BO = ½(B – A)
BO= Bond order
B= Number of bonding electrons
A = Number of antibonding electrons
For the sigma bonds, there are 2 bonding electrons and 0 nonbonding electrons.
σ BO = ½(B – A) = ½(2 – 0) = 1
π bond order for 6 C-C bonds;
π BO = ½(B – A) = ½(6 – 0) = 3
For each π bond, BO = 3/6 = 0.5.
Hence, for a single C-C bond in benzene, the total Bond order = σ + π = 1 + 0.5 = 1.5.
Is this the correct formula for magnesium acetate? Mg(C2H3O)2
Answer:
no
Explanation:
magnesium acetate= Mg(C2H3O2)2
In this stage of team building, the team is running smoothly and they are comfortable in their roles.
norming
performing
forming
storming
Answer:
performing
Explanation:
At STP, in the equation C(g) + O2(g) --> CO2(g), one liter of O2 yields how many liters of CO2?
Answer:
3 I think but ask someone else too
Would you expect a reaction to occur with Hydrogen gas and Copper (II) chloride?
The copper itself can react with hydrogen
Here is the chemical reaction
2CuCl2(aq) + H2(g) -> 2CuCl(s) + 2HCl(g)
In order to dissolve a chemical sample in a recrystallization solvent, add the room-temperature solvent ___________ in an Erlenmeyer flask on a hot plate. Turn on the heat, starting at __________________. Using a _______, add additional solvent from a second container on the heat source. Swirl the sample flask after each addition, and try to add _______________ in order to dissolve the solid.
Answer:
just until it covers the sample
a low setting and increasing gradually
pipet
as little solvent as possible
Explanation:
In order to dissolve a chemical sample in a recrystallization solvent, add the room-temperature solvent just until it covers the sample in an Erlenmeyer flask on a hot plate. Turn on the heat, starting at a low setting and increasing gradually. Using a pipet, add additional solvent from a second container on the heat source. Swirl the sample flask after each addition, and try to add as little solvent as possible in order to dissolve the solid.
the amount of copper sulphate used in dissolution is
Answer:
80 gm/mol
Explanation:
it may be helpful
The foam football Coach Johnson left in his chair will stay there until he
moves it to sit in the chair.
A. Newton’s first law
B. Newton’s second law
C. Newton’s third law
Answer:
B. Newton’s second law
Explanation:
correct me if im wrong
Answer:
Its c newton third law
Explanation:
His third law states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal and opposite force on object A. Notice that the forces are exerted on different objects.
Beryllium oxide, Beo, is an electrical insulator. How
many moles of beryllium oxide qre in a 250 gram
sample of the compound?
Answer:
There are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.
Explanation:
We can calculate the number of moles (η) of BeO as follows:
[tex] \eta = \frac{m}{M} [/tex]
Where:
m: is the mass = 250 g
M: is the molar mass = 25.0116 g/mol
Hence, the number of moles is:
[tex] \eta = \frac{250 g}{25.0116 g/mol} = 10.0 moles [/tex]
Therefore, there are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.
I hope it helps you!
Can someone help me please
Answer:
the answers are a, f, g
and lastly e because they all describe a liquid
structure of 2,6-diiodo-4-methyl-5-propylheptane
Explanation:
2,6-Dibromo-4-isopropylphenol
2432-16-8
2,6-dibromo-4-propan-2-ylphenol
Phenol, 2,6-dibromo-4-(1-methylethyl)-
4-isopropyl-2,6-dibromophenol
Which half reaction is associated with the anode?
Sn(s) —> Sn2+ (aq) + 2e-
Sn2+ (aq) + 2e- → Sn(s)
Pb2+ (aq) + 2e-->Pb(s)
Pb(s)->Pb2+ (aq) + 2e-
Answer:
vgf
Explanation:
Answer:
its either A or B
Explanation:
took the test twice and guessed LOL
its not C or D :>
To date, scientific tests of astrology have never found that its predictive methods work.
True
False
true______________________
Farsighted people have trouble seeing objects that are close to their eyes.
True
False
A taco from a fast food restaurant contains 7.0 g of fat, 25. g of carbohydrate, and 11 g of protein. How many kJ of energy does the cheeseburger contain? (The caloric values for foods are 38 kJ/g for fat, for carbohydrate, and 17 kJ/g for protein.)
Answer: 878 kJ of energy is there in cheeseburger
Explanation:
Given : calorific value of fat = 38kJ/g
calorific value of carbohydrate = 17 kJ/g
calorific value of protein = 17kJ/g
1 g of fat contains energy = 38 kJ
7.0 g of fat contains energy = [tex]\frac{38}{1}\times 7.0=266 kJ[/tex]
1 g of carbohydrate contains energy = 17 kJ
25 g of fat contains energy = [tex]\frac{17}{1}\times 25=425kJ[/tex]
1 g of protein contains energy = 17 kJ
11 g of protein contains energy = [tex]\frac{17}{1}\times 11=187kJ[/tex]
Total energy = (266+425+187) kJ = 878 kJ
molecular formula of CH3-CH2-CH2-CH2-CH2-Cl
Answer:
C₅H₁₁Cl
Explanation:
Count all the carbon, hydrogen, and chlorine atoms. The number of atoms of each element is the subscript for each element in the formula. No subscript is understood to be one. Carbon goes first, hydrogen goes second, and chlorine goes last when writing the formula.
What is full ground state electron configuration of C-?
Answer:
[tex]1s^{2}[/tex] [tex]2s^{2}[/tex] [tex]2p^{2}[/tex]
Explanation:
Simply [tex]1s^{2}[/tex] [tex]2s^{2}[/tex] [tex]2p^{2}[/tex]
Coal has two valent electrons, so there is 2 in 2p orbital
The eye can see colors because:
a. the cones in the retina send signals to the brain.
b. the rods in the cornea send signals to the brain.
c. the optic nerve determines the color of the object and sends signals to the brain
d. None of the choices are correct.
Answer:
The answer is A, I think.
Answer:
the answer is A
Explanation:
The human eye and brain together translate light into color. Light receptors within the eye transmit messages to the brain, which produces the familiar sensations of color. Newton observed that color is not inherent in objects. Rather, the surface of an object reflects some colors and absorbs all the others.
A tank contains one hundred fifty kmol of an aqueous phosphoric acid solution with 5.00 mole% H3PO4. The solution is concentrated by adding pure phosphoric acid at a rate of 30.0 L/min. Molecular weight of phosphoric acid is 98. Density of phosphoric acid is 1.834 kg/L. Determine the mole fraction of phosphoric acid in the tank at 25 minutes.
Answer:
Mole fraction = 0.1313
Explanation:
given data
Addition rate of pure phosphoric acid = 30L/min
Phosphoric acid added in 25 min = 750 L
solution
mass is express as here
mass = density × volume and number of moles = mass ÷ molar mass
So, In terms of moles
phosphoric acid added = (750 × 1.834) ÷ 98
phosphoric acid added = 14.036 kmol
and
moles of phosphoric acid in tank = 0.05 × 150 + 14.036
moles of phosphoric acid in tank = 21.536 kmol
and
Moles of water in tank = 0.95 × 150
Moles of water in tank = 142.5 kmol
So that Mole fraction of phosphoric acid in tank
Mole fraction = 21.536 ÷ (21.536+142.5)
Mole fraction = 0.1313
