Answer:
he thought of atoms first
Answer:
He was the first to be the one to propose that matter is made out of atoms. He also proved that the atoms are divisible in nature.
Builders and dentists must store plaster of Paris,
CaSO4 x 1/2 H2O, in airtight containers to prevent it from
absorbing water vapor from the air and changing to
gypsum, CaSO4 x 2H2O How many liters of water
vapor evolve when 2.00 kg of gypsum are heated at
110°C to produce plaster of Paris? At 110°C, the
density of water vapor is 0.574 g/L.
In order to determine the amount of water that evaporates from we need to convert the mass into volume.
What temperate is required to produce the POP ?The builders and the density use the plaster of Paris called POP and are a CaSO4 x 1/2 H2O is used for the airtight containers to stop them from taking in water vapors from the air and changes into gypsum that is CaSO4 x 2H2O. The answer is given as below. Answer:
The plaster of Paris is used for coating the walls and the celling from the aspects of molding. Its also used for casting decorative elements.
It absorbs water from the air and vapor evolves when the 2.00 kg of gypsum is heated at 110 degrees. C.
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When an F atom becomes an F-ion, the Fatom
gains a proton
gains an electron
loses an electron
loses a proton
When an F atom becomes an F-ion, the F atom gains an electron.
An atom is the smallest indivisible particle of an element. An atom consists of proton, electron and neutron, which are called subatomic particles. An atom becomes charged when it loses or gains an electron. The charged atom is called an ion. An atom loses electrons to become positively charged i.e. a cation while it gains electrons to become negatively charged i.e. an anion. Therefore, when an F atom becomes an F-ion, this means that the F atom gains an electron.Learn more at: https://brainly.com/question/13495616?referrer=searchResults
The Fluoride ion given has a -ve charge onto it. Thus in order to become stable Fluorine gains an electron. Thus option b is correct.
The elements in the periodic table try to attain the stable noble gas configuration in the order to become stable. The noble gas configuration has the elements to be less reactive.
When the atom loses an electron in order to become more stable, a +ve charge has been implemented onto the ion.
When the atom gains an electron to become stable, a -ve charge has been added to the ion.
The Fluoride ion given has a -ve charge onto it. Thus in order to become stable Fluorine gains an electron. Thus option b is correct.
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In a science experiment, 10 tomato plants were given fertilizer in their water each week and 10 tomato plants were given plain water each week. All other factors were the same for all plants. At the end of each week, the height of each plant was measured. What was the independent and dependent in the experiment?
1. the height of the plant
2. the amount of water given
3. the type of plant
4. whether or not there was fertilizer in the water
Answer:
Independent: whether or not there was fertilizer in water
Dependent: height of plants
Explanation:
In an experiment, there is an independent and a dependent variable. The independent variable is what is changed in the experiment. The dependent variable is what is measured.
In this experiment, 10 tomato plants are given fertilizer in the water, while 10 other tomato plants are given regular water. Everything else is kept constant, and the heights are measured at the end of the week.
The independent variable is what is being changed. In this experiment, the only thing being manipulated is the fertilizer. One group of the plants is given fertilizer, while the other is not. Therefore, the independent variable is whether or not there was fertilizer in the water.
The dependent variable is what is being measured. In this experiment, the thing that is being measured is the height of the plants. Therefore, the dependent variable is the height of the plants.
What is the yield of uranium from 2.50 kg U3O8?
Answer: Thus the yield of uranium from 2.50 kg [tex]U_3O_8[/tex] is 2.12 kg
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number [tex](6.023\times 10^{23})[/tex] of particles.
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{molar mass}}[/tex]
moles of [tex]U_3O_8=\frac{2.50\times 1000g}{842g/mol}=2.97mol[/tex] (1kg=1000g)
As 1 mole of [tex]U_3O_8[/tex] contains = 3 moles of U
2.97 mole of [tex]U_3O_8[/tex] contains = [tex]\frac{3}{1}\times 2.97=8.91moles[/tex] moles of U
Mass of Uranium=[tex]moles\times {\text {Molar mass}}=8.91mol\times 238g/mol=2120g=2.12kg[/tex]
( 1kg=1000g)
Thus the yield of uranium from 2.50 kg [tex]U_3O_8[/tex] is 2.12 kg
calculate the ph and poh of a 0.0032 M solution of nitric acid NHO3
Answer:
HNO3 ->NO3²- + H+
Concentration of H+ ions= 0.0032M
pH = - log[ H+]
= - log (0.0032)
= 2.49
pH + pOH = 14
pOH = 14 - pH
= 14 - 2.49
= 11.51
pH = 2.49 and pOH = 11.51
Hope this helps.
A.
B.
C.
D.
Help me please?
Answer:
B: it allow quick conversation to others
What is the total energy change for the following reaction: H2 + I2 -> 2HI?
Given:
H-H bond: 436 kJ/mol
I-I bond: 151 kJ/mol
H-I bond: 297 kJ/mol
A. +7 kJ/mol
B. +297 kJ/mol
C. -290 kJ/mol
D. -7 kJ/mol
Energy change is the conversion of the energy stored in reactants to products. In the reaction between hydrogen and iodine, the energy change is -7 kJ/mol. Thus, option D is correct.
What is total energy change?Total energy change is the conversion of the energy from a substance to another when the reactant undergoes modification to produce a product.
The reaction is given as,
H₂ + I₂ → 2HI
In the reaction, the bonds between H-H and I-I are broken to release energy that produces two H-I bonds as the product.
Given,
H-H bond = 436 kJ/mol
I-I bond = 151 kJ/mol
H-I bond = 297 kJ/mol
So, 436 kJ/mol + 151 kJ/mol - 2x297 kJ/mol = -7 kJ/mol
Therefore, -7 kJ/mol is the total energy change in the reaction involving hydrogen and iodine.
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Why does an ultraviolet light cause paint to fade
Answer:
There are light absorbing color bodies called chromophores that are present in dyes. Ultraviolet rays are one of the causes of fading because they can break down chemical bonds and fade the color in objects.
Two boxes need to be moved into storage. Jamal and Jude each want to move a box. The force of gravity on both the boxes is 50 N. Jamal is lifting with a force of 60 N, and Jude is lifting with a force of 45 N. Which best describes the movement of the boxes? Jamal moved his box to storage, but Jude could not move his. Jamal and Jude can successfully move each box into storage. Jamal could not move his box to storage, but Jude could. Neither Jamal nor Jude could move the boxes into storage.
Answer: 80
Explanation:
Answer:
Jamal moved his box to storage, but Jude could not move his.
Explanation:
The force they exert needs to be higher than the force of gravity in order for them to move the boxes. Jamal's force is 60N, which is 10N above the force of gravity on the box, which is 50N. However, Jude's force is only 45N and that is lower than 50N, so he won't be able to move the box while Jamal can.
A solution is made by mixing 114.g of benzene C6H6 and 83.g of acetyl bromide CH3COBr. Calculate the mole fraction of benzene in this solution. Round your answer to 3 significant digits.
A solution is made by mixing 114.g of benzene C6H6 and 83.g of acetyl bromide CH3COBr, the mole fraction of benzene in this solution is 1.45mol.
What is molar mass ?The term molar mass is defined as the compound is often calculated by adding the quality atomic masses in g/mol of the constituent atoms.
Molar mass of CH3COBr,
Molar Mass = 2 × MM(C) + 3 × MM(H) + 1 × MM(O) + 1 × MM(Br)
= 122.944 g/mol
Molar mass of C6H6,
MM = 6 × MM(C) + 6 × MM(H)
= 6 × 12.01 + 6 × 1.008
= 78.108 g/mol
n(CH3COBr) = mass/molar mass
= 83 /122.944
= 0.675
n(C6H6) = mass/molar mass
= 114 / 78.108
= 1.45
n(CH3COBr),n1 = 0. 675mol
n(C6H6),n2 = 1. 45mol
Thus, the mole fraction of benzene in this solution is 1.45mol.
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CHEMISTRY PUNKS PLEASE HELP ME OUT!!!!!!!!!!!!!!!!! PLS. ILL LOVE U FOREVER N EVER! any point stealers will be reported <3
Answer: 25.0 L
Explanation:
For this problem, we will need to use Boyle's Law.
Boyle's Law: P₁V₁=P₂V₂
Since we are looking for V₂, we can rewrite the equation.
V₂=P₁V₁/P₂
The pressure should be in atm, so let's convert kPa to atm.
P₁=100 kPa=0.99 atm
P₂=200 kPa=1.97 atm
Now that we know the pressure in atm, we can plug it into the equation and solve.
[tex]V_{2} =\frac{(0.99 atm)(50.0L)}{1.97atm}[/tex]
[tex]V_{2} =25.0 L[/tex]
Propenoic acid is an unsaturated carboxylic acid. Describe how you could show
that it is an unsaturated compound giving details of the test and the result.
Answer:
Tests for unsaturation involves addition across the multiple bonds in the unsaturated compound.
Explanation:
In organic chemistry, we define an unsaturated compound as any compound that contains a double or triple bond. These multiple bonds are also known as pi bonds.
There are two major tests for unsaturation which shall both be discussed here.
The first test for unsaturation is by the use of bromine water. The unknown sample is passed through a solution of bromine water which normally appears reddish brown. The bromine water becomes decolorized due to addition of bromine across the multiple bond. This is a standard test for unsaturation.
Secondly, unsaturated compounds decoulourize a solution of potassium permanganate when passed through it. This alone can not be used as a distinctive test for unsaturation.
Propenoic acid will give a positive test to the both reagents showing that it contains multiple bonds, in this particular instance, a double bond.
Determine the boiling point of a 3.70 m solution of phenol in benzene. Benzene has a boiling point of 80.1°C and a boiling point elevation constant of 2.53°C•kg/mol.
Answer: The boiling point of a 3.70 m solution of phenol in benzene is [tex]89.5^0C[/tex]
Explanation:
Elevation in boiling point:
[tex]\Delta T_b=i\times k_b\times m[/tex]
where,
[tex]\Delta T_b[/tex] = change in boiling point
i= vant hoff factor = 1 (for benzene which is a non electrolyte )
[tex]k_b[/tex] = boiling point constant = [tex]2.53^0C/kgmol[/tex]
m = molality = 3.70
[tex]T_{solution}-T_{solvent}=i\times k_b\times m[/tex]
[tex]T_{solution}-80.1^0C=1\times 2.53\times 3.70[/tex]
[tex]T_{solution}=89.5^0C[/tex]
Thus the boiling point of a 3.70 m solution of phenol in benzene is [tex]89.5^0C[/tex]
Answer:
First Question:
C. ΔTb = Kbm
Second Question:
C. 9.36° C
Third Question:
89.5
Explanation:
Got it right.
What is the temperture at which all molecular movements stop called
Answer:
Absolute Zero
Explanation:
at 0 Kelvin, nothing can move and entropy reaches 0
Answer:
absolute zero
Explanation:
Calcium carbonate, when heated, forms calcium oxide and carbon dioxide. 100grams of calcium carbonate will produce 56grams of calcium oxide. How many grams of carbon dioxide will it produce? Show working out
Answer:
It will produce 44 grams of carbon dioxide
Explanation:
Step 1: Data given
MAss of CaCO3 = 100 grams
Molar mass of CaCO3 = 100.09 g/mol
Mass of CaO produced = 56 grams
Molar mass of CaO = 56.08 g/mol
Step 2: The balanced equation
CaCO3 → CaO + CO2
Step 3: Calculate moles CaCO3
Moles CaCO3 = mass CaCO3 / molar mass CaCO3
Moles CaCO3 = 100 grams / 100.09 g/mol
Moles CaCO3 = 1.00 moles
Step 4: Calculate moles CaO
Moles CaO = 56 grams / 56.08 g/mol
Moles CaO = 1.00 moles
Step 5: Calculate moles CO2
For 1 mol CaCO3 we'll have 1 mol 1 mol CaO and 1 mol CO2
Step 6: Calculate mass CO2
Mass CO2 = moles CO2 * molar mass CO2
Mass CO2 = 1.00 moles * 44.0 g/mol
Mass CO2 = 44 grams
It will produce 44 grams of carbon dioxide
The forces between water molecules are stronger
than the forces between ethanol molecules. Which
liquid would probably be most difficult for an insect
to walk on? Explain your answer.
Answer:
An insect would have an easier time walking on the surface of water than on the surface of ethanol.
Water's stronger intermolecular forces lead to higher surface tension.
Higher surface tension allows water to support the insect.
Answer:
An insect would have an easier time walking on the surface of water than on the surface of ethanol.
Water's stronger intermolecular forces lead to higher surface tension.
Higher surface tension allows water to support the insect.
Explanation:
In the movie bee movie how does the bee berry communicate
Answer:
they stick together as a group and that they berly fought or argue
Answer:first get a jar
Explanation:
Patrick that’s a jokers side special
Which of the following symbols would be included in the noble gas notation for an element that had valence electrons in the
5s subshell?
A) Ar
B) Kr
C) Хе
D) Rn
Would be appreciated if I could get a quick answer. Thank you in advance.
Answer: C.) Xe
Explanation: To figure out the answer go to the Noble Gas Family and count down 5 elements.
According to the electronic configuration the symbol which would be included in the noble gas notation for an element that had valence electrons in the 5 s subshell is xenon .
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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56. What would be the valence electrons of 14Si, 16S, 32Ge respectively?
A. 4, 2,2
B. 4, 6,8
C. 4, 6,6
D. 4,6,4
Answer: D. 4,6,4
Explanation:
The valence electron is the electron found in the outermost shell of an atom, and participates in bond formation.
For the following element, the valence electron can be noticed when we write the electronic configuration of each element.
Silicon = 1s2 2s2 2P6 3s2 3p2
Sulphur = 1s2 2s2 2P6 3s2 3p4
Germanium = 1s2 2s2 2P6 3s2 3p6 3d10 4s2 4p2
If the temperature outside is 297 what is this temperature in degrees celsius
Answer:
147.222
Explanation:
It's a simple conversion.
If the pH of a solution is 6.2, what would the pOH be?
O A. 7.8
B. 8.9
C. 12.4
D. 5.8
SUBMIT
Answer:
7.8
Explanation:
pH + pOH = 14
pOH = 14 - 6.2
= 7.8
Which of the following elements have the same number of valence electrons?
I. Nitrogen (N)
II. Oxygen (O)
III. Fluorine (F)
IV. Sulfur (S)
V. Selenium (Se)
find the volume of the prism iready help me please
Answer:
The answer is 80!
Explanation:
A prism is a three dimensional solid object in which the two ends are identical. It is the combination of the flat faces, identical bases and equal cross sections. The volume of the prism is 819 cm³.
What is the volume of the prism?A prism is a polyhedron with two parallel congruent faces called the bases that are polygons. The volume of a three dimensional solid is the amount of space it occupies. The volume is measured in cubic units. The volume can be denoted in m³, cm³, ft³, etc.
The volume of a prism is the area of the base times the height. The equation used to calculate the volume is:
Volume = Base area × Height
Here the rectangle has 9cm length and 7cm width. Then the area is:
Area = 9 × 7 = 63 cm²
The height of prism = 13 cm
Then the volume is:
V = 63 × 13 = 819 cm³
Thus the volume of the prism is 819 cm³.
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Your question is incomplete most probably your full question was
What is volume of the rectangular prism with length 9cm, width 7cm and height 13 cm?
Select all statements that are true for Sn1 reactions. (a) Formation of the carbocation is the rate-determining step (RDS) (b) The reaction rate depends upon the concentration of both the nucleophile and the electrophile (c) Reactions at chiral carbons proceed with inversion of stereochemistry (d) None of these statements are true for Sn1 reactions (e) Carbocation rearrangements are never observed
Answer:
(a) Formation of the carbocation is the rate-determining step (RDS)
(c) Reactions at chiral carbons proceed with inversion of stereochemistry
Explanation:
SN1 reactions arenucleophilic substitution reactions in which the rate determining step is unimolecular.
The formation of a carbocation is the rate determining step. This depends on the electrophilicity of the leaving group. Thus the SN1 reaction mechanisms is dependent on the electrophile and not the nucleophile.
Polar and acidic solvents which can assist in the formation of the carbocation speeds up the rate determining step.
If the formation of carbocation occurs at a chiral center, both retention and inversion of stereochemistry are likely to occur.
Therefore, the correct options are A and C.
QUESTION 20 Which of the following is a producer? oak tree raccoon cockroach human
Answer:
may be the first one is a producer
What is the mole ratio between NH3 and H2O in the following reaction:
4NH3(g)+ 6NO(g)----->5N2(g) +6H2O(l)
Answer:
1 mole of nitrogen (N2) reacts with 3 moles of hydrogen (H2) to form 2 moles of ammonia (NH3) ... 4 NH3 (g) + 5 O2 (g) --> 4 NO (g) + 6 H2O (g) ... Example: What is the molar ratio between Li and N2 in the following reaction
Explanation:
1 mole of nitrogen (N2) reacts with 3 moles of hydrogen (H2) to form 2 moles of ammonia (NH3) ... 4 NH3 (g) + 5 O2 (g) --> 4 NO (g) + 6 H2O (g) ... Example: What is the molar ratio between Li and N2 in the following reaction
Which of the following is a polyatomic ion?
O A N₂
B. HCl
O C. S2
O D. PO43-
Answer:
The answer is D..i.e phosphate. it consists of 1p and 4oxygen atoms
[tex]PO_4^{3-}[/tex] is a polyatomic ion. Hence, option D is correct.
What is a polyatomic ion?
Polyatomic ions are ions which consist of more than one atom.
The prefix poly- means many, so a polyatomic ion is an ion that contains more than one atom. This differentiates polyatomic ions from monatomic ions, which contain only one atom.
[tex]PO_4^{3-}[/tex] is a chemical derivative of phosphoric acid with a chemical name Phosphate. Phosphate is also called Phosphate ion or Orthophosphate.
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Which balanced equation represents an oxidation-reduction reaction?
Answer:
Oxidation states are used in chemistry solutions. It is a bond in which electron transfers easily from one nucleus to another nucleus.
Explanation:
Oxidation-reduction reactions have some rules.The oxidation state is 0 at an uncombined bond.The bond of oxidation reduction is +1 in alkeli metal. The bond in two metal is +2The oxidation reduction state at helogens is -1. It does not happened always.The oxygen bond in oxidation and reduction is -2. The sum of the oxidation state is equal to the compound charges.In this process the changes occur for any elements. Redox could be occur. Its oxidized and reduction reaction can be seen in this process.What is the voltage of an electrolytic cell with copper and magnesium
electrodes?
A. 2.71 V
B. -2.71 V
C. 2.03 V
D. -2.03 V
Answer:
A. 2.71 V
Explanation:
The standard reduction potential, E° of the metals are as follows:
Mg²⁺ + 2e⁻ ⇌ Mg; E° = -2.372
Cu²⁺ + 2e⁻ ⇌ Cu; E° = +0.337
Since magnesium has the the lower E°, it will serve as the anode in the electrolytic cell while copper will serve as the cathode.
At the anode; Mg ⇌ Mg²⁺ + 2e⁻, E° = -2.372
At the cathode; Cu²⁺ + 2e⁻ ⇌ Cu, E° = +0.337
EMF of the cell = E° cathode - E° anode = 0.337 - (-2.372) = 2.71 V
Therefore, EMF of the cell is 2.71 V
Answer:-2.71 is the correct answer
Explanation:
A P E X
Which is one way that waves erode coastlines?
Answer:
Four main processes erode the destructive waves; hydraulic action, compression, abrasion and attrition. Hydraulic Action is the sheer force of water crashing off the coastline causing the material to dislodge and be carried away by the sea.
Answer:
a
Explanation:
