Answer:
The mechanical properties of urea formaldehyde resins may be improved by incorporating therein polyvinyl alcohol. The polyvinyl alcohol may be incorporated during pre-mixing, mid mixing, and/or post mixing of the resin components. Resins prepared using polyvinyl alcohol are particularly desirable in articles requiring improved mechanical strength and water resistance, as compared to similar resins prepared without the polyvinyl alcohol such as shingles.
What is the quantity of
heat required to raise the
temperature of 500 g of
iron by 2°C?
The specific heat capacity
of iron is 500 J/(kg °C)
Answer:
The quantity of heat required to raise the temperature of 500 g of iron by 2°C is 500 J.
Explanation:
Calorimetry is responsible for measuring the amount of heat generated or lost in certain physical or chemical processes.
The sensible heat of a body is the amount of heat received or transferred by a body when undergoing a temperature variation (Δt) without there being a change in physical state (solid, liquid or gaseous).
Its mathematical expression is the fundamental equation of calorimetry. This is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case:
Q= ?c= 500 [tex]\frac{J}{kg*C}[/tex]m= 500 g= 0.500 kgΔT= 2 CReplacing:
Q= 500 [tex]\frac{J}{kg*C}[/tex] *0.500 kg*2 C
Solving:
Q= 500 J
The quantity of heat required to raise the temperature of 500 g of iron by 2°C is 500 J.
The carbon-carbon bonds in benzene are:
O a) Easily broken in chemical reactions
b) A hybrid between double bonds and single bonds
c)
Identical to the carbon-carbon bonds in cyclohexene
d) Identical to the carbon-carbon bonds in cyclohexane
please hurry
Answer:
a
Explanation:
Easily broken in chemical reactions
The formula for europium oxide is Eu203. On the basis of this information, the formula for the chlorate of europium would be expected to be
Answer:
Eu(ClO3)3
Explanation:
The chlorate ion is written as follows, ClO⁻ ₃. We can see from this that the ion is univalent.
From the formula, Eu203, it is easy to see that the europium ion is trivalent.
Hence, when a compound is formed between the europium ion and chlorate ion, the compound will be written as Eu(ClO3)3.
This is so because, when ionic compounds are formed, there is an exchange of valence between the ions in the compound. This gives the final formula of the ionic substance.
A student named a particular compound 2-ethyl-3-methyl-2-butene. Assuming that the student's choice actually corresponded to the correct distribution of the double bond and the substituents, what is the correct IUPAC name for this compound
Answer:
2-ethyl-3-methylbut-2-ene
Explanation:
The whole idea of IUPAC nomenclature is to devise a universally accepted system of writing the name of a compound from its structure.
According to IUPAC nomenclature, the root of the compound is the longest carbon chain. The substituents are named in alphabetical order and in such a way as to give each one the lowest number. The position of the functional group is indicated accordingly.
For the compound in question, its correct IUPAC name is 2-ethyl-3-methylbut-2-ene.
Calculate [H3O+] and [OH−] for each of the following solutions at 25 ∘C given the pH.
pH= 2.89
Answer: The value of [tex][H_{3}O^{+}][/tex] is 0.0012 M and [tex][OH^{-}][/tex] is [tex]1.02 \times 10^{-14}[/tex].
Explanation:
pH is the negative logarithm of concentration of hydrogen ion.
It is given that pH is 2.89. So, the value of concentration of hydrogen ions is calculated as follows.
[tex]pH = - log [H^{+}]\\2.89 = - log [H^{+}]\\conc. H^{+} = 0.0012 M[/tex]
The relation between pH and pOH value is as follows.
pH + pOH = 14
0.0012 + pOH = 14
pOH = 14 - 0.0012 = 13.99
Now, pOH is the negative logarithm of concentration of hydroxide ions.
Hence, [tex][OH^{-}][/tex] is calculated as follows.
[tex]pOH = - log [OH^{-}]\\13.99 = - log [OH^{-}]\\conc. OH^{-} = 1.02 \times 10^{-14} M[/tex]
Thus, we can conclude that the value of [tex][H_{3}O^{+}][/tex] is 0.0012 M and [tex][OH^{-}][/tex] is [tex]1.02 \times 10^{-14}[/tex].
heating, the particle _______________ increases as more __________ __________ is added
Answer: what are the choices?!.
Explanation:
A solution has a [H3O+] of 1 × 10−5 M. What is the [OH−] of the solution?
A) 9 M
B) 14 M
C) 1 x 10^{-9}
D) 1 x 10^{-14}
which is a characteristic of oxygen
Answer:
Characteristics of oxygen are as follows:
In normal conditions oxygen is a colourless, odourless and insipid gas.It condensates in a light blue liquid.Oxygen is part of a small group of gasses literally paramagnetic and it's the most paramagnetic of all.Liquid oxygen is also slightly paramagnetic.pasagot po please!!
science po ito pasagot po matino need ko po!!
Explanation:
Efficiency = (output/input)×100%
70% = output/(800 W)
which means
output = 0.70×(800 W) = 560 W
5 compounds that has electrovalent and covalent bond
Answer:
electrovalent
NaCl
Lithium Carbonate
ammonium phosphate
aluminium floride
potassium hydride
covalent
methane
benzene
carbon iv oxide
hydro flouride
hydro chloride
What is the concentration of s solution that contains 55 mL of alcohol per 145 mL solution?
Answer:
37.9% v/v
Explanation:
Since both the alcohol and solution are presumed to be liquid, this concentration can be expressed as a volume concentration (or % v/v):
volume concentration = volume of solute / volume of solution
[tex]\% v/v = 55/145= 0.379[/tex]
1. How many atoms of chlorine are present in 1.70x1023 molecules Cl2?
Explanation:
the answer is in the image above
Consider the following reaction at 298 K.
2 SO2(g) + O2(g) → 2 SO3(g)
An equilibrium mixture contains O2(g) and SO3(g) at partial pressures of 0.43 atm and 2.6 atm, respectively. Using data from Appendix 4, determine the equilibrium partial pressure of SO2 in the mixture.
______atm.
Answer and Explanation:
The reaction is in the gas phase, so the equilibrium constant is expressed in terms of the partial pressures (P) of the products and reactants, as follows:
[tex]Kp = \frac{P^{2}_{SO_{3} } }{P_{SO_{2}} ^{2}P_{O_{2}} }[/tex]
We have the following data:
P(SO₃) = 2.6 atm
P(O₂) = 0.43 atm
We need Kp for this reaction. We can assume that in Appendix 4 we found that Kp = 7 x 10²⁴.
Then, we introduce the data in the equilibrium constant expression to calculate the partial pressure f SO₂ (PSO₂), as follows:
[tex]P_{SO_{2} } = \sqrt{\frac{P_{SO_{3} } ^{2} }{Kp P_{O_{2} } } } = \sqrt{\frac{(2.6 atm)^{2} }{(7 x 10^{24)}(0.43 atm) } } = 1.5 x 10^{-12} atm[/tex]
Therefore, the partial pressure of SO₂ is 1.5 x 10⁻¹² atm (for the given Kp).
Electron sharing can be depicted by a Lewis dot structure, in which element symbols are surrounded by dots that represent the valence electrons (electrons in the ___________ shell). A ______________ bond is the sharing of a pair of valence electrons by _____________ atoms. Hydrogen has _____________ valence electron(s) in the first shell, but the capacity of the shell is ______________ electron(s). When a hydrogen atom comes close enough to a carbon atom for their orbitals to overlap, they can share their electrons. The hydrogen atom is now associated with _______________ electron(s) and a ______________ bond is formed. As a result, one of the structures does not make sense because hydrogen has only ____________ valence electron(s) to share, so it cannot form bonds with two atoms.
Answer:
Outermost
Covalent
Two
One
Two
Two
Covalent
One
Explanation:
A covalent bond is formed when an atom shares two electrons with another atom. These shared electrons could be contributed by each of the bonding atoms or by only one of the bonding atoms.
Hydrogen has the electronic configuration of 1s1. This implies that it has only one electron in its valence shell although the 1s shell can accommodate two electrons. When the atomic orbitals of carbon and hydrogen overlap, they share two electrons and hydrogen is now associated with two electrons in a covalent bond.
Since hydrogen possesses only one valence electron, it can not be bonded to two atoms.
A solution of KMnO4 has an absorbance of 0.539 when measured in the colorimeter. Determine the concentration of the KMnO4 given the following data for a calibration plot.
Concentration of KMNO4 (M) Absorbance
0.0150 0.081
0.0300 0.159
0.0450 0.260
0.0600 0.334
Answer:
Concentration of unknown solution is 0.0416 M
Explanation:
As we know
Absorbance is equal to the product of molar absorptivity of KMnO4 m, path length and concentration
From the given set of graphical data, it is clear that the absorbance vs concentration is a straight line.
From the graph, we can obtain-
Y = 5.73 X – 0.0065
Absorbance = 0.232
0.232 = 5.73 X – 0.0065
X = 0.0416
Concentration of unknown solution is 0.0416 M
a. Compound A and compound B are constitutional isomers with molecular formula C3H7Cl. When compound A is treated with sodium methoxide, a substitution reaction predominates. When compound B is treated with sodium methoxide, an elimination rection predominates. Propose structures A and B.
b. An unknown compound with molecular formula C6H13Cl is treated with sodium ethoxide to produce 2,3-dimethyl-2-butene as the major product. Identify the structure of the unknown compound.
Answer:
história phkfk
Explanation:
guiooupigjdytrss
Lab 2: paper chromatography of organic dyes
Picture of questions below.
Answer:
The three primary colors used when mixing dyes or paints are red, yellow, and blue. Other colors are often a mixture of these three colors. Try running a chromatography test again with non-primary-color markers, like purple, brown, and orange.
Explanation:
Mixtures that are suitable for separation by chromatography include inks, dyes and colouring agents in food. ... As the solvent soaks up the paper, it carries the mixtures with it. Different components of the mixture will move at different rates. This separates the mixture out.
The seagulls on the beach -
Dugongs are animals that live in the ocean and eat underwater grasses. The sun is shining on the shallow ocean water where the grasses and dugongs live.
What is happening to the carbon in the water around the grasses and the dugongs? Is carbon moving into the water, moving out of the water, or both?
Answer:
please mark as brainliest
Explanation:
The sun is shining on the shallow ocean water where the grasses and dugongs live. What is happening to the carbon in the water around the grasses and the dugongs? Is carbon moving into the water, moving out of the water, or both? Carbon is not moving into the water; it is only moving out of the water.
A 14.570 g sample of CaCl2 was added to 12.285 g of K2CO3 and mixed in water. A 3.494 g yield of CaCO3 was obtained.
What is the limiting reagent?
-CaCO3
-K2CO3
-CaCl2
Calculate the percent yield of CaCO3.
yield of CaCO3= %
Answer:
Limiting reagent is the potassium carbonate.
Percent yield of calcium carbonate is: 39.3 %
Explanation:
The reaction is:
CaCl₂ + K₂CO₃ → CaCO₃ + 2KCl
Formula for percent yield is:
(Produced yield / Thoeretical yield) . 100
Firstly we determine the moles of each reactant, in order to say what is the limiting reagent: ratio is 1:1.
1 mol of chloride need 1 mol of carbonate.
14.570 g . 1 mol /110.98 g = 0.131 moles of CaCl₂
12.285 g . 1 mol / 138.2g = 0.0889 moles of carbonate.
Limiting reagent is carbonate. For 0.131 moles of CaCl₂ we need the same amount of carbonate and we have less moles.
Ratio is also 1:1, with calcium carbonate.
1 mol of potassium carbonate produces 1 mol of calcium carbonate
then, 0.0889 moles will produce the same amount of CaCO₃
We convert moles to mass: 0.0889 mol . 100.08g /mol = 8.89 g
That's the theoretical yield; to find the percent yield:
(3.494 g / 8.89g) . 100 = 39.3%
atomic number of element is 15 write a formula of an oxide
Answer:
Atomic Number. 15=phosphorus
Valency=3
So, Oxide=P203
How do we fix climate change?
The biggest problem of course is conspiracy theorys. Some say it is just a hoxe when really their chidrin or grandchidrin will sufer greatly from it. How do we educate ourselfs better?
Answer:
Hi so your answer is that to helping fix the climate change you have to : speak up , power your home with renewable engery , reduce water waste , dont waste food , and finally invest energy .
Explanation:
Really hope i helped , have a nice day :)
Answer:
we can reduce air pollution,which is one of the main cause of climate change.Climate change is not a hoxe if it is not attending the upcoming generations will suffer greatly.
carbon dioxide gas evolve during the fermentation of sugar which was collected at 22.5°C and 0.945 ATM after perfect strangers in the volume was found to be 25.0 ML how many grams of carbon dioxide were collected
Answer:
0.043 grams
Explanation:
We can find the mass of carbon dioxide as follows:
[tex] m = n*M [/tex]
Where:
n: is the number of moles
M: is the molar mass = 44.01 g/mol
First, we need to calculate the number of moles. We can use the Ideal gas equation:
[tex] PV = nRT [/tex]
Where:
P: is the pressure = 0.945 atm
V: is the volume = 25.0 mL
R: is the gas constant = 0.082 L*atm/(K*mol)
T: is the tempearture = 22.5 °C
[tex]n = \frac{PV}{RT} = \frac{0.945 atm*25 mL*\frac{1 L}{1000 mL}}{0.082 L*atm/K*mol*(22.5 + 273) K} = 9.75 \cdot 10^{-4} moles[/tex]
Hence, the mass is:
[tex]m = 9.75 \cdot 10^{-4} moles*44.01 g/mol = 0.043 g[/tex]
Therefore, 0.043 grams were collected.
I hope it helps you!
Molybdenum (Mo) crystallizes with a body-centered cubic lattice and has an atomic radius of 136.1 pm.
a. Calculate the density of molybdenum in g/cm^3. Show all work. Include units with all numbers and show how units cancel.
b. Calculate the density of molybdenum in g/cm^3
In an oxidation-reduction reaction, the substance oxidized always ________. a. takes on oxygen atoms b. gives up hydrogen atoms c. gains electrons d. loses electrons e. becomes a charged species
Answer:
Explanation:
Let us define oxidation and reduction.
Oxidation and reduction deal with the transferring of electrons between reactants. The reactant that loses electrons is oxidized, while the reactant that gains electrons is reduced.
In an oxidation-reduction reaction, the substance oxidized always loses electrons and the correct option is option D.
An oxidation-reduction (redox) reaction is a type of chemical reaction that involves the transfer of electrons between species. It consists of two half-reactions: an oxidation half-reaction, where a species loses electrons and increases its oxidation state, and a reduction half-reaction, where a species gains electrons and decreases its oxidation state.
In an oxidation half-reaction, the species that is oxidized is called the reducing agent or the electron donor, as it donates electrons. In a reduction half-reaction, the species that is reduced is called the oxidizing agent or the electron acceptor, as it accepts electrons.
Thus, the ideal selection is option D.
Learn more about Oxidation-reduction reactions, here:
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The product of an organic reaction is analyzed by column chromatography using silica as the stationary phase and toluene as the mobile phase.
a. True
b. False
Answer:
The product of an organic reaction is analyzed by column chromatography using silica as the stationary phase and toluene as the mobile phase.
Explanation:
The given statement is true.
In chromatography silica gel is used as the predominant stationary phase.
Since silica gel is a good adsorbent.
It is a polar adsorbent.
In order to remove polar components, silica gel is used as the stationary phase.
Answer is a.true.
Which event is an example of melting?
A. Wax drips down the side of a lit candle.
B. Perspiration dries on a person's skin.
C. Rain turns to ice pellets.
D. A mirror fogs up when someone takes a hot shower.
I’m just curious tbh
Answer:
A. Wax drips down the side of a lot candle.
Explanation:
The chemical change from solid to liquid. This is a combustion reaction, so carbon dioxide gas and water vapour is also produced but you can't see them
Answer:
A. Wax drips down the side of a lot candle.
Explanation:
For each molecule, specify the polarity of the bonds and the overall polarity of the molecule.
a. BeCl2
b. H2O
c. O3
13. The attraction between water molecules and an Na+
ion or a Cl- ion occurs because water molecules are
A) linear
B) symmetrical
C) polar
D) nonpolar
Answer:
C) Polar
Explanation:
The correct answer is polar
The attraction of sodium and chloride ions by the water is mediated by the polar nature of water. Thus, option C is correct.
What is polarity?The polarity is given as the formation of the partial positive and negative charge over the species in the ionization process.
Water molecule is having one hydrogen bounded with 2 oxygen atoms, and oxygen being more electronegative develops a partial negative charge, while hydrogen develops a partial positive charge.
The positive charge hydrogen and the negative charge oxygen attracts the opposite charge sodium and chloride ions. Thus, the attraction is mediated due to the polar nature of water. Hence, option C is correct.
Learn more about polarity, here:
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A 8.29g sample of calcium sulfide was decomposed into its constituent elements, producing 4.61g of calcium and 3.68g of sulfur. Which of the statements are consistent with the law of constant composition (definite proportions)?
a. Every sample of calcium sulfide will have 44.4% mass of calcium.
b. Every sample of calcium sulfide will have 2.86 g of calcium.
c. The mass ratio of Ca to S in every sample of calcium sulfide is 1.25.
d. The ratio of calcium to sulfur will vary based on how the sample was prepared.
e. The mass percentage of calcium plus the mass percentage of sulfur in every sample of calcium sulfide equals 100%.
Answer:
d,e
Explanation:
