Answer:
A: COAL
Explanation:
Coal was created hundreds of millions years ago. When prehistoric plant life died and sank to the bottom of the swamp and was covered by layers of sediment.
What is the main goal of cloning? A. To make living things that have identical DNA
B. To improve the process of asexual reproduction
C. To add medicines to the foods that people eat
D. To spread genes from transgenic plants to wild plants
Answer:
A
Explanation:
A p e x
How did Henry Moseley affect the development of the periodic table?
Answer: "In 1913 he used self-built equipment to prove that every element's identity is uniquely determined by the number of protons it has."
Explanation: If you are using this in an essay, use your own words when you use this. I got this from a website. But I hope it helps!
What may form when magma comes to the surface?
Answer
When magma reaches the surface it is called lava. After lava has cooled it forms solid rock.
Answer:
Volcano
Explanation:
when magma reaches the surface it cools and then magma will start coming out over and over and over again. Then we have a volcano. hopemthis helps
If 17.8 g grams of lithium (Li) are combined with 50.0 grams of water (H20) there is
24.7 grams of hydrogen gas (H2) produced. How much lithium hydroxide (LiOH) was
also produced?
Answer:
Explanation:
Li+H2O..................LiOH+H2
mass of Li=17.8 g
No of moles of Li=17.8/7=2.5
mass of H2O=50.0 g
No of moles of H2O=50.0/18=2.8
limiting reagent is Li so 1 mole of Li produce 1 mole of LiOH therefore 2.5 mole of Li produce 2.5 moles of LiOH now we have to convert it into grams
moles=given mass/molar mass
given mass=moles*molar mass
molar mass of LiOH=24
mass=2.5*24=60 gram
Which substance has the most thermal energy and will have the most heat flow from it?
A. a stovetop burner on medium (200°C)
B. a nuclear reactor core (1000°C)
C. the human body (36°C)
D. air at room temperature (32°C)
Answer:
B. a nuclear reactor core (1000°C)......
A 50.0 mL sample of HCl required 25.81 mL of 0.1250 M KOH for neutralization. What is the molarity of the acid?
Answer:
0.065M
Explanation:
The reaction expression is given as:
HCl + KOH → KCl + H₂O
Given parameters:
Volume of KOH = 25.81mL = 0.02581L
Molarity of KOH = 0.125M
Volume of HCl = 50mL = 0.05L
Unknown:
Molarity of the acid = ?
Solution:
To find the molarity of the acid, HCl, let us use the mole concept.
First, find the number of moles of the base, KOH;
Number of moles of KOH = molarity of KOH x volume of KOH
Number of moles of KOH = 0.125 x 0.0258 = 0.003225mol
From the balanced reaction equation:
1 mole of KOH reacted with 1 mole of HCl
0.003225mol of KOH will react with 0.003255mole of HCl
Molarity of HCl = [tex]\frac{number of moles of HCl}{Volume of HCl}[/tex]
Molarity of HCl = [tex]\frac{0.003255}{0.05}[/tex] = 0.065M
A rectangular solid has the following measurements 6 cm, 10 cm, and 5 cm. what is the volume of the solid?
How often waves repeat is called their
Answer:
Wave Frequency
Calculate the volume occupied by 55.5 moles of water at STP.
Answer:
Volume occupied by 55.5 moles of water gas at STP = 1240 Liters.
Explanation:
1st keep in mind that 'volume' in the context of problems like this apply only to the gas phase form of the substance. Water in solid form (ice) or liquid form (liquid water) do not apply. Volume in this case is referred to as 'molar volume' and is a gas occupying 22.4 liters at STP conditions (0°C, 1Atm).
So, if 1 molar volume of water gas (steam) occupies 22.4 Liters at STP, then 55.5 moles of water gas occupies 22.4 Liters/mole x 55.5 moles = 1243.2 Liters, or 1240 Liters (3 sig. figs.). :-)
.What is the effective number of bonds between the sulfur atom and each oxygen atom in the sulfate ion
Answer:
The effective number of bonds in sulfate ion is 1.5
Explanation:
The number of chemical bonds between two atoms is known as the bond order.
In covalent bonds between two atoms, a single bond has a bond order of one, a double bond has a bond order of two, a triple bond has a bond order of three.
If there are more than two atoms in a molecule, the effective number of bonds can be determined by applying the following steps:
1. Draw the Lewis structure.
2. Count the total number of bonds.
3. Count the number of bond groups between individual atoms.
4. Divide the number of bonds between atoms by the total number of bond groups in the molecule.
For the sulfate ion, the resonance structure is shown in the attachment below. From the structure;
Total number of bonds = (2 × 2) + (2 × 1) = 6
Total number of bond groups = 4
Effective number of bonds = 6/4 = 1.5
Therefore, the effective number of bonds in sulfate ion is 1.5
One mole of an ideal gas expands reversibly and isothermally from 10. bar to 1.0 bar at 298.15K.
Required:
a. Calculate the values of w, q, âU and âH?
b. Calculate w if the gas were to have expanded to the same final state against a constant pressure of 1 bar.
Answer:
a. W = 5,708 J, Q = 5,708 J, ΔU = 0 and ΔH = 0.
b. 2,231 J.
Explanation:
Hello!
a. In this case, since this is an isothermal process (constant temperature) it is possible to infer that the work is computed as shown below:
[tex]W=nRTln(\frac{p_1}{p_2} )=1mol*8.314\frac{J}{mol*K}*298.15Kln(\frac{10.bar}{1.0bar} )\\\\W=5708J[/tex]
Now, since this is an isothermal process we know by definition ΔU = 0 and ΔH = 0, therefore the involved heat is:
[tex]Q-W=0\\\\Q=W=5708J[/tex]
b. In this case, since the process is isobaric but goes to the same final volume in part a, we can compute the initial and final volume based on the part a's conditions by using the ideal gas equation:
[tex]V_1=\frac{nRT}{p_1} =\frac{1mol*0.083145\frac{*L}{mol*K}*298.15K}{10.bar} =2.48L\\\\V_2=\frac{nRT}{p_2} =\frac{1mol*0.083145\frac{*L}{mol*K}*298.15K}{1.bar} =24.8L[/tex]
Thus, the work done here is:
[tex]W=p(V_2-V_1)=1bar(24.8L-2.48L)=22.3bar*L*\frac{1x10^5Pa}{1bar} *\frac{1m^3}{1000L} \\\\W=2231J[/tex]
Best regards!
A covalent bond is formed by:
loss of electrons between atoms
sharing of electrons between atoms
gain of electrons between atoms
valence electron shells overlaping, forming a "sea of electrons"
Answer:
sharing of electrons between atoms
The 38 elements in groups 3 through 12 of the periodic table are called "Alkaline Earth Metals" O True O False
Answer:
FALSE
they're called transition metals
Answer:
false
Explanation:
The 38 elements in groups 3 through 12 of the periodic table are called "transition metals." As with all metals, the transition elements are both ductile and malleable, and conduct electricity and heat.
Pleaseeee help I’m stuck on this problem
What is the mole fraction of KCI in a
mixture of 0.564 g NaCl, 1.52 g KCI,
and 0.857 g LICI?
Answer:
0.4
Explanation:
Given parameters:
Mass of NaCl = 0.564g
Mass of KCl = 1.52g
Mass of LiCl = 0.857g
Unknown:
Mole fraction of KCl = ?
Solution:
First, find the number of moles of the given species;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of KCl = 39 + 35.5 = 74.5g/mol
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Molar mass of LiCl = 7 + 35.5 = 42.5g/mol
Number of moles of KCl = [tex]\frac{1.52}{74.5}[/tex] = 0.02mol
Number of moles of NaCl = [tex]\frac{0.564}{58.5}[/tex] = 0.0096mol
Number of moles of LiCl = [tex]\frac{0.857}{42.5}[/tex] = 0.02mol
Sum of moles = 0.02mol + 0.0096mol + 0.02mol = 0.0496mol
Mole fraction of KCl = [tex]\frac{0.02}{0.0496}[/tex] = 0.4
Answer:
.4
Explanation:
Which property (volume , mass , or density) is a measure of the space it takes up?
Answer:
mass
Explanation:
Calculate the amount of grams of water that was used when 5525J of energy was used to boil this amount of water.
Answer:
2.445 g
Explanation:
Step 1: Given and required data
Energy in the form of heat required to boil the water (Q): 5525 JLatent heat of vaporization of water (∆H°vap): 2260 J/gMass of water (m): ?Step 2: Calculate the mass of water
We will use the following expression.
Q = ∆H°vap × m
m = Q / ∆H°vap
m = 5525 J / (2260 J/g)
m = 2.445 g
How many atoms of hydrogen would need to bond with a single atom of selenium to form a molecular compound?
Answer:
Hydrogen sulfide reacts with aqueous selenous acid to produce selenium disulfide:
H2SeO3 + 2 H2S → SeS2 + 3 H2O
Selenium disulfide consists of 8-membered rings. It has an approximate composition of SeS2, with individual rings varying in composition, such as Se4S4 and Se2S6. Selenium disulfide has been used in shampoo as an antidandruff agent, an inhibitor in polymer chemistry, a glass dye, and a reducing agent in fireworks.[15]
Selenium trioxide may be synthesized by dehydrating selenic acid, H2SeO4, which is itself produced by the oxidation of selenium dioxide with hydrogen peroxide:[17]
SeO2 + H2O2 → H2SeO4
Hot, concentrated selenic acid can react with gold to form gold(III) selenate.[18]
IMESSAGE GAMES ANYONE?
Answer:
oop whats dis
Explanation:
How many grams of KOH are required to prepare 500. mL of 0.450 KOH solution?
Answer:
KOH molar mass = 39 + 16 + 1 = 56g
To make 1 L of 1M soln needs 56g KOH
To make 500mL 1M needs 56/2 = 28g
To make 500mL 0.2M needs 28 x 0.2gn:
Question 1 Give the correct number of significant figures for 4500, 4500., 0.0032, 0.04050
Question 2 Give the answer to the correct number of significant figures:
4503 + 34.90 + 550 = ?
the correct number of significant figures.
uction 2 Give
Answer:
Question 2
5087.9 or 5088
Object A has a molar heat of 31.2 J/mole∙°C and object B molar heat is 11.2 J/mole∙°C. Which object will heat up faster if they have the same mass and equal amount of heat is applied? Explain why.
Answer:
Substance B
Explanation:
Molar heat of A = 31.2J/mole.°C
Molar heat of B = 11.2 J/mole∙°C.
The molar heat of a substance is the amount of heat that must be added to a mole of a substance to raise the temperature by 1°C.
Substance B will heat up faster compared to A. It has a smaller molar heat compared to A. This suggests that it will require lesser heat to raise its temperature by 1°C.A tea kettle on a hot burner. Point A is steam coming from the spout. Point B is the heat source. Use the drop-down menu to choose the type of thermal energy transfer shown at each point in the image. A: B:
Answer:
A : convection
B : conduction
Explanation:
Answer:
A. Convection
B. Conduction
Explanation:
What is the balanced NET ionic equation for the reaction when aqueous Cs₃PO₄ and aqueous AgNO₃ are mixed in solution to form solid Ag₃PO₄ and aqueous CsNO₃
Answer:
[tex]PO_4^{3-}(aq)+3Ag^+(aq)\rightarrow Ag_3PO_4(s)[/tex]
Explanation:
Hello!
In this case, since the net ionic equation of a chemical reaction shows up the ionic species that result from the simplification of the spectator ions, which are those at both reactants and products sides, we take into account that aqueous species ionize into ions whereas liquid, solid and gas species remain unionized. In such a way, for the reaction of cesium phosphate and silver nitrate we can write the complete molecular equation:
[tex]Cs_3PO_4(aq)+3AgNO_3(aq)\rightarrow Ag_3PO_4(s)+3CsNO_3(aq)[/tex]
Whereas the three aqueous salts are ionized in order to write the following complete ionic equation:
[tex]3Cs^+(aq)+PO_4^{3-}(aq)+3Ag^+(aq)+3NO_3^-(aq)\rightarrow Ag_3PO_4(s)+3Cs^+(aq)+3NO_3^-(aq)[/tex]
In such a way, since the cesium and nitrate ions are the spectator ions because of the aforementioned, the net ionic equation turns out:
[tex]PO_4^{3-}(aq)+3Ag^+(aq)\rightarrow Ag_3PO_4(s)[/tex]
Best regards!
Write the balanced equation for the reaction that occurs when aluminum bromide is mixed with potassium sulfate forming potassium bromide and aluminum sulfate
Answer:
2AlBr₃ + 3K₂SO₄ → 6KBr + Al₂(SO₄)₃
Explanation:
Given species;
Reactants
Aluminum bromide = AlBr₃
Potassium sulfate = K₂SO₄
Products
Potassium bromide = KBr
Aluminum sulfate = Al₂(SO₄)₃
So, the reaction equation is given as:
AlBr₃ + K₂SO₄ → KBr + Al₂(SO₄)₃
To balance this chemical equation, let us an algebraic approach;
aAlBr₃ + bK₂SO₄ → cKBr + dAl₂(SO₄)₃
Conserving Al;
a = 2d
Conserving Br;
3a = c
Conserving K;
2b = c
Conserving S;
b = 3d
Conserving O;
4b = 12d
if a = 1;
c = 3
b = [tex]\frac{3}{2}[/tex]
d = [tex]\frac{1}{2}[/tex]
Now, multiply through by 2;
a = 2, b = 3, c = 6 and d = 1
2AlBr₃ + 3K₂SO₄ → 6KBr + Al₂(SO₄)₃
A 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate (KHP, formula mass = 204.22 g/mol) is diluted to 250.0 mL. What is the molarity of the final solution?
Answer:
[KHP] = 0.0428M
Explanation:
2 methods to calculate concentration after dilution
1. Use dilution equation
Molarity of concentrate (M₁) x Volume of Concentrate (V₁)
= Molarity of dilute (M₂) x Volume of dilute (V₂)
M₁ x V₁ = M₂ x V₂ => M₂ = M₁ x V₁ / V₂ = (1.07M)(10ml)/(250ml) = 0.0428M
2. Concentration Equation
moles KHPh = Molarity (M) x Volume (V) = 1.07M x 0.010L =0.0107 moles KHP
Concentration KHP = moles solute / volume of solution in Liters
= 0.0107 moles KHP / 0.25L = 0.0428M
The molarity of 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate diluted to 250.0mL is 0.0428M.
HOW TO CALCULATE MOLARITY:
The molarity of a diluted solution can be calculated by using the following formula:C1V1 = C2V2
Where;
C1 = initial concentration of solutionC2 = final concentration of solutionV1 = initial volume of solutionV2 = final volume of solutionAccording to this question,
C1 = 1.07MC2 = ?V1 = 10.0mLV2 = 250mL1.07 × 10 = C2 × 25010.7 = 250C2C2 = 10.7 ÷ 250C2 = 0.0428MTherefore, the molarity of 10.00 mL sample of a 1.07 M solution of potassium hydrogen phthalate diluted to 250.0mL is 0.0428M.Learn more about how to calculate molarity of a solution at: https://brainly.com/question/13386686?referrer=searchResults
The survival of aquatic organisms depends on the small amount of O2 that dissolves in H2O . The diagrams above represent possible models to explain this phenomenon. Which diagram provides the better particle representation for the solubility of O2 in H2O , and why?
Answer:
Diagram 1
Explanation:
The solubility of the oxygen gas in water has to do with the interaction of the oxygen with the dipoles in water.
Water is a polar molecule having oxygen as the negative dipole and hydrogen as the positive dipole.
Water can interact with the oxygen atoms in the molecule via intermolecular hydrogen bonds with molecular oxygen as shown in diagram 1.
What is the reason for the trend in Atomic Radii? Select all that apply.
A. number of valence electrons.
B. number of neutrons in the nucleus
C. number of protons in the nucleus
D. larger atomic mass number
E. number of energy levels around the nucleus
A student masses a green crystal sample and records 1.253 grams. He then dissolves the green crystal in water and does a titration, and calculates that his sample has 7.35x10-3 moles of C2O4-2.
What is the percent of C2O4-2 in the sample?
a. not enough information is given
b. 51.63%
c. 129%
d. 0.5866%
e. 20.62%
Answer:
b. 51.63%
Explanation:
Step 1: Given data
Mass of the sample: 1.253 gMoles of oxalate (C₂O₄²⁻): 7.35 × 10⁻³ molStep 2: Calculate the mass corresponding to 7.35 × 10⁻³ moles of oxalate
The molar mass of C₂O₄²⁻ is 88.02 g/mol.
7.35 × 10⁻³ mol × 88.02 g/mol = 0.647 g
Step 3: Calculate the mass percent of oxalate in the sample
% w/w = mass of oxalate / mass of the sample × 100%
% w/w = 0.647 g / 1.253 g × 100%
% w/w = 51.63%
pretty please help me (:
Okay I need an explanation from YOU. when is this due? If it’s last minute, why didn’t you do it when you had time? This is very irresponsible, unless you have a personal reason. Please quit commenting on others just for the points. I helped you with one, because I thought it was just one question you needed help with. No one is going to finish this for you. I’m sorry but it’s the truth, everyone here needs help. No one is here TO help. So please be cooperative and try to learn. Of course, I’m sorry if it is for a very personal reason as it happens to everyone where you need the work ASAP because of a reason. Hopefully, it’s not because you were lazy. Appreciate your education as not many people in the world have it.
Which are functions of the stomata in the leaves of seed plants? Check all that apply.
-reduce water loss
-make glucose
-absorb sunlight
-take in carbon dioxide
-produce oxygen
NEED CORRECT ANSWER ASAP BEING TIMED
Answer:
Take in carbon dioxide, reduces water loss, and produce oxygen.
Explanation: Hi! I've learned about these things in the past, really tough stuff! Hopefully this helps, I believe the three options above are correct, only one I'm possibly questioning is producing oxygen. Good luck!
Answer:
Take in carbon dioxide, reduces water loss
Explanation: