Answer:
it talks about reality ..how animals and human came to existence and how they disappear ..this is evolution
the environment chooses those who best fit in it and others are selected ..as in die ..this is referred to as natural selection
and further in this theory .animals produce off springs who survive in the environment
On a plateau on a heating curve, _____.
phase changes are occurring
no heat is being absorbed
all the absorbed heat is being used to overcome forces of attraction between the particles or molecules and phase changes are occurring
all the absorbed heat is being used to overcome forces of attraction between the particles or molecules
Answer:
On a Plateu on a heating curve phase changes are occuring
Explanation:
The first Phase is melting during which the temrature stays the same while water melts.Other phase changes are freezing sublimation Vaourization condensation and deposition
8. What is the oxidation number of N in KNO3?
Answer:
The oxidation state of N in the KNO3 is +5
Explanation:
Oxidation rules:
1. Oxygen is -2, unless in peroxides.
2. Group 1 metals = +1
3. Group 2 metals = +2
4. If the molecule is neutral, all of the oxidation numbers have to add up to zero.
5. If the molecule is charged, all of the oxidation numbers have to add up to the charge of the molecule.
So, the given formula represents the salt compound formula unit of potassium nitrate: KNO3
The formula unit is uncharged.
From our rules, we know that,
O = -2
And we can find K on the periodic table, in the first group, thus giving it a +1 charge. Now let's put it all together.
K = +1
N = x
O = -2
Let's take into account the number of atoms of each element we have and make an equation since we know everything has to add up to zero since the molecules are neutral.
+1 +x+3 (-2) = 0 (notice we multiplied 3 by -2 because in the formula we have 3 atoms of oxygen with -2 charge each)
x - 5 = 0
x = 5
Therefore, the oxidation number of N in KNO3 is +5.
what is solution, colloid, suspension?
Explanation:
SOLUTION:Solution is a homogenous mixture of two or more substances in relative amounts that can be varied continuously up to what is called the limit of solubility.
COLLOID:A mixture in which one substance is divided into minute particles (called colloidal particles) and dispersed throughout a second substance
SUSPENSION:A suspension is a heterogeneous mixture of a finely distributed solid in a liquid. The solid is not dissolved in the liquid, as is the case with a mixture of salt and water.
6. What parts of a nuclear reactor keep the reaction from
becoming too vigorous and causing a nuclear accident?
A. Turbine and generator
B. Control rods and moderators
C. Shield and containment system
D. Condenser and cooling tower
Answer:
B. control rods and moderators
What makes a strong acid different from a weak acid?
Answer:
Strong acids react faster whereas weak acids take time to react with any base.
Strong acids are good conductors of electricity on contrary weak acids are not too good as conductors of electricity.
Strong acid passes electricity faster whereas weak acids are slow conductors.
Strong acids are not edible but weak acids are edible.
Strong acids have ph value ranging between 0 to 3 but the ph value of weak acids ranges between 5 to below 7.
. The Ksp of barium sulfate is 1.1 × 10–10. What is the sulfate-ion concentration of a 1.0-L saturated solution of BaSO4 to which 0.025 mol of Ba(NO3)2 is added? 4.4 × 10–9M 1.0 × 10–5M 6.6 × 10–5M 2.8 × 10–12M
Answer:
[tex][SO_4^{2-}]=4.4*10^{-9}M[/tex]
Explanation:
From the question we are told that:
[tex]Ksp=1.1*10^{-10}[/tex]
Volume of [tex]SO_4^{2-}=1.O[/tex]
Moles of [tex]Ba(NO_3)^2 =0.025[/tex]
Generally the equation for Ksp is mathematically given by
[tex]Ksp=[Ba^{2+}][SO_4^{2-}][/tex]
[tex]1.1*10^{-10}=[0.025][SO_4^{2-}][/tex]
Therefore
[tex][SO_4^{2-}]=4.4*10^{-9}M[/tex]
solve this
The first one is the Bromine water test
the second is the Baeyers test
Third is addition reaction
1 CH3-CHBR-CH2BR
2.CH3-CH2-CH3
3.CH3-CHCL-CH2CL
Oxoacids have the general formula illustrated, where the number of bonds to the central element E can vary. For the same element E, acid strength will _____ as the number of O atoms increases. For the same number of O atoms, acid strength increases as the _____ of element E increases. Multiple choice question. decrease; electronegativity
Answer:
Hence the correct answer is increase, electronegativity.
Explanation:
Oxoacids have the general formula illustrated, where the number of bonds to the central element E can vary. For the same element E, acid strength will increase as the number of O atoms increases. For the same number of O atoms, acid strength increases as the electronegativity of element E increases.
For the following reaction of N2O4, the equilibrium constant is 0.593 at a particular temperature.
N2O4(g) ⇌ 2 NO2(g)
If the initial concentration of N2O4 is 0.880M, what are the equilibrium concentrations?
Please show work!
Answer:
"0.583" is the appropriate answer.
Explanation:
Let,
The initial constant of [tex]N_2O_4[/tex] be "C".
Amount of [tex]N_2O_4[/tex] dissociated into [tex]NO_2[/tex] be "x".
now,
[tex]N_2O_4 \rightleftharpoons 2NO_2[/tex]
Initial constant C -
Equilibrium constant C 2x
The Kc is given as:
⇒ [tex]K_c = \frac{[NO_2]^2}{[N_2O_4]}[/tex]
[tex]=\frac{(2x)^2}{C-x}[/tex]
[tex]0.593=\frac{4x^2}{0.88-x}[/tex]
[tex]4x^2=0.593(0.88-x)[/tex]
[tex]4x^2=0.512-0.593\ x[/tex]
[tex]x=0.291[/tex]
hence,
The constant of [tex]NO_2[/tex] will be:
= [tex]2x[/tex]
= [tex]0.583[/tex]
which best describes the relationship between internal energy and thermal energy
Answer:
answer is d on edge
Explanation:
15 ft is the same as how many yards
............................
Chemicals used in hot packs do not produce fire, so what makes the hot packs feel hot?
Answer:
chemical wsed in hot packs do not produce fire, so what makes the hot packs feel hot? Because it is a exothermic reaction it has chemicals that bunch up together.
The table below gives the equilibrium concentrations for this reaction at a certain temperature : N2(g) + O2(g) 2NO(g) what is the equilibrium constant for the reaction?
A. 1 x 10-5
B. 7 x 10-3
C. 70
D. 100
The equilibrium concentrations for the given reaction at a certain temperature will be 100.
What is equilibrium?During a reversible chemical process, chemical equilibrium is the state where there would be no net change in the number of reactants as well as products.
What is the reaction?The reaction is the process in which by the combination of more than one element new kind of element will be formed.
Given data:
The given reaction is [tex]N_{2} (g) + O_{2} (g)[/tex] → [tex]2NO(g)[/tex]
The equilibrium constant (K) = [tex][NO]^{2} /[N_{2}][O_{2}][/tex]
Put the value of the given data in the above equation.
K = [tex]=[0.002 M]^{2} / [0.65M][0.45M]\\=[4*10^{-6} ]/ [0.2950]\\= [4*10^{-6} ] / 2950*10^{-4}\\= 1.35 * 10^{-5}[/tex]
Therefore, the equilibrium constant will be 1.35 × [tex]10^{-5}[/tex]
To know more about reaction and equilibrium
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what is the molarity of HCL solution that has a density of 1.17g/ml at 25°?
Here, we have been given that;
$ \bf{1 ml}$ = 1.17 g$ \bf{1 l}$ = 1170 gHence, we can note that,
No. of moles of HCL (n) = $ \sf{\frac{1170}{36.5}}$(n) = 32.05
[tex] \\ [/tex]
Thus,
Molarity = 32.05 mg/LHence, molarity of the given solution will be 32.05 mg/L.
Calculate the volume (in L) that 3.25 mol of helium gas will occupy at a temperature of 25.0 °C and a pressure of 799 mm Hg.
Answer:
V = 6.34 L
Explanation:
Given that,
Number of moles of Helium gas, n = 3.25 mol
Temperature, T = 25 °C = 298 K
Pressure, P = 799 mm Hg
We know that,
PV = nRT
Where
R is the gas constant, R = 62.4 L-mm Hg/mol K
So,
[tex]V=\dfrac{nRT}{P}\\\\V=\dfrac{3.25\times 62.4\times 25}{799}\\\\V=6.34\ L[/tex]
So, the volume of the gas is 6.34 L.
What is the name of the molecule shown below?
A) ethanol
B) ethanal
C) ethanoic acid
D) ethylamine
The name of the molecule shown is Ethanol.
What is Ethanol?Ethanol is a alcoholic substance that is formed from fermentation of glucose in the presence of yeast or microorganisms.
It has a chemical group that have methyl group, hydroxyl group OH which is bonded to carbon atom.
Therefore, The name of the molecule shown is Ethanol.
Learn more about ethanol below.
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plz answer (g) i will give rating 5 and thanks who answer plz fast
Answer:
Like many common group 2 metal carbonates, magnesium carbonate reacts with aqueous acids to release carbon dioxide and water
MgCO3 + 2 HCl → MgCl2 + CO2 + H2O.
The procedure to obtain pure magnesium chloride from the reaction is as thus
Step 1: Reaction
- Leave the dilute hydrochloric acid in a beaker.
- Add Magnesium carbonate slowly until it is in excess or until no more gas seem to be getting liberated.
Step 2: Filtration
- Filter with filter paper and funnel.
- Filter off the excess magnesium carbonate as magnesium chloride will be in aqueous form (liquid) and will come out with the filtrate. The residue is the excess magnesium carbonate.
Step 3: Crystallization to obtain solid crystals from the filtrate.
- Pour filtrate solution into evaporating dish/basin
- Provide heat using Bunsen burner
- Pour solution into an evaporating basin and heat over a water bath
- Stop heating when crystals start to form
allow water to evaporate until pure crystals remain.
- Dry crystals using absorbent paper or warm oven.
Precautions
- Use personal protective equipment such as gloves, a lab coat and wear eye protection, especially when heating.
- Avoid inhaling unnecessary gases during the whole process.
0 / 5 points
Order the following chemicals from lowest to highest melting point.
Water
Paraffin wax
Hydrogen sulfide
Ethanol
Carbon dioxide
Answer:
Ethanol - -173.5°FHydrogen sulfide - -121.9°FCarbon dioxide - -69.9 °FWater - 32°FParaffin wax - 115 to 154 °FExplanation:
Ethanol is a chemical, grain alcohol is a volatile and flammable, colorless, and odorless substance. The versatile solvent has many acidic compositions. Paraffin wax is an soft and colorless solid that is made from petroleum coal and oil. It is an excellent material for storing heat.nhóm nào gồm tất cả các kim loại tan trong axit sunfuric đặc nóng nhưng không tan trong axit sunfuric loãng là
Answer:Nhóm gồm tất cả các kim loại tan trong axit sunfuric đặc nóng nhưng không tan trong axit sunfuric lo
Al, Cu, Au.
Al, Fe, Cr.
Ag, Fe, Pt.
Ag, Cu, Hg.
Explanation:
True or false, We use the ideal gas law when a gas changes
we use the ideal has law when a bad changes false
what structure does solid lead (11)fluoride have
Calculate the solubility of Maslog at 25€
4 30-0cm of its Saturated solution at that
temperature gave 180g of the anhydrous
C= 12. 0-46. Ma =23
Salt
Answer:
20
Explanation:
calculated saturated solutions
HELP ME PLZ Which of the following describes the structure of a fish's swim bladder?
A. Expands and contracts to allow the fish to rise or sink in the water
B. Internal organ filled with liquid
c. Holds urine until it can be released into the environment
D. Internal organ filled with air sacs
Help please and thank youu
Answer:
elementos original
set onde
how many grams of potassium cyanide would be needed to make a saturated solution for the volumes indicated below? The solubility of potassium cyanide is 50.0g/100ml
A. 0.150L
B. 75.0mL
C. 1.10L
D. 225mL
What is chemical reaction ?
Answer:
CHEMICAL REACTION : A process in which new substances with new properties are formed from one or more substances.
REACTANTS - Substances which take part in a chemical reaction.PRODUCTS - Substances which are formed in a chemical reaction.Examples of chemical reactions : Digestion of food, respiration, rusting of iron, burning of magnesium ribbon, formation of curd etc.
Answer:
Explanation:
Chemical reaction is one or more reactants react with each other to from new products.
Situación 1: Cierto catión divalente posee 2 electrones en n=5. Además, su número de masa es igual a 118. Hallar lo siguiente:
1. Su distribución electrónica
2. Su número de neutrones
3. Protones más electrones
4. Sus posibles números cuánticos de su último electrón
…………………………………………………………………………………………………
El catión divalente descrito en la pregunta es [tex]Sn^{2+}[/tex]. Divalente significa que ha perdido dos electrones.
La distribución electrónica de [tex]Sn^{2+}[/tex] es;
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10
El número másico de estaño es 118 y [tex]Sn^{2+}[/tex] tiene 50 protones.
Por lo tanto, el número de masa de Sn =[tex]118 - 50 = 68 neutrones[/tex]
El número de electrones es 49 y el número de protones es 50 en [tex]Sn^{2+}[/tex]por tanto;
El número de electrones + protones = 99
El último electrón está en el orbital, 5s2, por lo que sus posibles números cuánticos son;
n = 5, l = 0, m = 0, s = ±1/2
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Predict what would happen if a scientist added potassium to a dilute acid.
Potassium reacts with dilute hydrochloric acid to give potassium chloride and hydrogen gas. Heating small pieces of Potassium in air results in the substance melting without any flame being seen and turning instantly into a mixture of potassium peroxide and potassium super oxide.
A Potassium Reaction involves a process in which Potassium is mixed with another substance which react to form something else. Reactions are manifested by the disappearance of properties characteristic of Potassium and the appearance of new properties in the new substance or Compound.
The substances initially involved in a reaction are called reactants or reagents. The most important of the Potassium compounds is Potassium chloride (KCl) which is used in the production of fertilizers and chemicals and also as a salt substitute. Other important compounds are Potassium nitrate (KNO3), also known as saltpeter which is used in the production of gunpowder, fertilizers and pyrotechnics and Potassium hydroxide (KOH) is used to make detergents and soaps. Reactions are described with Chemical Formula and Equations.
Calcium sulfate is a white solid found as two hydrates, a hemihydrate known as plaster of Paris and a dehydrate known as gypsum. The hemihydrate is a white solid. Given that the molar mass of the anhydrous calcium sulfate is 136.14 g/mol, the molar mass of the hemihydrate is 145.15 g/mol, and the molar mass of water is 18.015 g/mol, which formula gives the correct ratio for the hemihydrate
Answer:
2(CaSO4)*H2O
Explanation:
To solve this question we need to find the moles water, H2O, of calcium sulfate, CaSO4 as follows:
The molar mass of the anhydrous CaSO4 are 136.14g/mol and the molar mass of the hemihydrate is 145.15g/mol. The differences in molar mass represents the additional mass that water is producing:
145.15g/mol - 136.14g/mol = 9.01g/mol
A 1 mole of water weighs 18.015g/mol, the additional mass of water is due the addition of 1/2 moles of H2O. That means we have 1 mole of CaSO4 per 1/2 mole of H2O. That is the same:
2(CaSO4)*H2O
And this is the formula that gives the correct ratio for the hemihydrate.
