Answer:
the bond that hold the ionic solids together is the ionic bond while the force that holds them together is the electrostatic force.
Explanation:
what do the conclusions tell about the experiments?
A) the conclusions tell what other scientists think about the experiment
B) the conclusions tell how the experiments should be repeated
C)the conclusions tell why the data support or reject the hypothesis
D) the conclusions tell if the scientific method was followed
Help Please !!!!!!!!!!!!!!!!
Answer:
C
Explanation:
APEX
the conclusions of an scientific experiment tell why the data support or reject the hypothesis. Thus option C is correct.
What is scientific experiment ?Scientific experiment involve asking different scientific questions, making hypothesis, design experiment, result and conclusion.
A good scientific experiment should have some facts which can be answered by using data analysis.
The types of scientific questions are Verification questions, Theory questions, Experimental questions
The verification question can be solved by collecting data from observation, which include characteristics or properties of a subject.
A theory question refers an imaginative exercise, is not fictional, depend on prior knowledge of the phenomenon being asking about.
The scientific question or an experimental question used to compare the element of a system when altered, it involves variables such as independent, dependent and controlled variables.
Thus option C is correct.
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Answer my question please
Answer:
Explanation:F
16. State one advantage and disadvantage
of rusting
Answer:
Advantage:
It forms ferrous oxide which is used as a pigment for glasses
Disadvantage:
It destroys the appearance of the metal and weakens it.
Answer:
Advantage: Rusting provides a thin durable shell to prevent the metal from getting more corroded.
Disadvantage: Rusting weakens material due to prolonged corrosive action.
Explanation:
Formula los siguientes compuesto: Dietil eter, Etanol, Propanotriol, Acido Propanodioico, Pentanal, Pentano-2,4-diona, Metanoato de metilo, Ciclohexano-1,3-diol, Acido heptanoico, Ciclobutil metil éter, acetato de etilo, 2-metilbenzaldehído, Ciclohexanona, Butanona
Answer:
Explanation:
En este caso para formular los compuestos, debes identificar el grupo funcional principal de la molecula. Una vez que eso está hecho, puedes intentar formularlo.
Empezaremos primero identificando el grupo funcional principal de la molécula, para luego formularlo correctamente.
Dietil eter: la terminación eter al final significa que pertenece al grupo de los éteres, el cual tiene como formula general R - O - R.
Etanol: debido a que termina en ol, este grupo pertenece a los alcoholes. Para formularlo solo se dibuja la molecula del etano, junto a un enlace con el grupo OH, como su formula general R - OH.
Propanotriol: igualmente termina en ol, por lo tanto es un alcohol, sin embargo, en este caso, tambien tiene la terminación prefija tri, asi que significa que hay 3 grupos OH en la molecula.
Acido propanodioico: esta es sencilla, porque empieza como acido, y solo hay un grupo funcional que empieza así y son los acidos carboxilicos, es decir, el grupo COOH (R - COOH) que es el carboxilo. Tiene el prefijo di, antes del oico, por lo que son dos carboxilos presentes en la molecula.
Pentanal: el sufijo al, significa que pertenece al grupo de los aldehidos, en este caso, posee el grupo carbonilo H - C = O.
Pentano - 2,4 - diona: la terminación ona significa que pertenece al grupo de las cetonas, (R - CO - R), parecido a los aldehidos, con la diferencia de que tiene grupos alquilos en lugar de un hidrogeno.
Metanoato de metilo: la terminación ato de ilo, pertenece a los esteres, (R - COOR) derivado de los acidos carboxilicos.
De aqui en adelante solo mencionaré los grupos funcionales pues ya se explicó el por que, por sus terminaciones:
Ciclohexano - 1.3 - diol: este pertenece a los alcoholes.
Acido heptanoico: acido carboxilico
Ciclobutil metil eter: eteres
Acetato de etilo: ester
2-metilbenzaldehído: aldehído unido a un grupo aromatico como el benceno.
Ciclohexanona: un ciclo (cadena cerrada) unido a un grupo carbonilo.
Butanona: cetona.
Observa la foto adjunta para que veas la formulación de cada una:
Mendeleev's periodic table of elements was created in 1901.
O A. True
O B. False
Explanation:APΕX
Predict the arrangement of the following substances in decreasing order of pH value Orange juice || Bitter gourd juice || Hydrochloric acid || Mineral water
Answer:
Mineral water> Bitter gourd juice> Orange juice> Hydrochloric acid
Explanation:
pH is referred to as the degree of acidity or alkalinity of a substance. The pH scale is arranged from 0-14. Substance with a pH of 0-6.9 are acid, a pH of 7 indicates neutrality while a pH of 8-14 indicates alkalinity.
Mineral water is usually slightly acidic with a pH between 5-6. The pH of bitter gourd juice is between 4.24-4.45. The pH of orange juice ranges between 3.3 to 4.2 lastly, the pH of hydrochloric acid is about 3.01.
The pH values itemized above informed the arrangement of decreasing pH values shown in the answer box.
In order to answer this question, you need to look around your immediate surroundings to find examples of rusting of iron or any other metal. i. What makes iron rust? ii. Why is the rusting of iron a problem? Give any 3 examples from daily life where rusting has been a disadvantage. iii. Suggest any two ways that can help prevent rusting of iron.
Answer:
(i) rusting is caused by the reaction of oxygen and water on the surface of metals(iron).
(ii) rusting of iron makes it weak and dangerous for buildings since their foundation is made of iron, rusting renders cars useless, rusting can cause accidents.
(iii) by galvanizing iron
and by coating it.
Explanation:
hope it helps .
hello can you please help me to solve above questions. .
Answer:
i)a. P & R
b. Q& S
ii) R
iii) Atomic no & Atomic radius
2)a. C4H10
b. CH3Cl
What is the pH of a 0.45 M solution of hydrochloric acid
pH = 0.35
Explanation: hope this helps
Answer: 0.35
Explanation:
A gas sample that has a pressure of 4.23 atm, a volume of 1,870 mL, and a temperature of 293 K is allowed to expand to a volume of 6.01 L with a final temperature of 373 K. What is the final pressure of the gas in atmospheres?
Answer:
1.68 atm.
Explanation:
Given:
P1 = 4.23atm
V1 = 1870 mL
T1 = 293K
P2 = ?
V2 = 6.01 L = 6010 mL
T2 = 373 K
Assuming number of moles and R is constant:
[tex]\frac{P1V1}{T1} = \frac{P2V2}{T2}[/tex]
⇒ P2 = [tex]\frac{P1V1T2}{T1V2}[/tex] = [tex]\frac{2,950,467.3}{1,760,930}[/tex]
= 1.68 atm.
Which is true about reaction rates?
1. High reaction rates occur only in spontaneous reactions.
2. Low reaction rates occur only in nonspontaneous reactions.
3. Reaction rates are not dependent on high or low activation energies.
4. Reaction rates are not related to spontaneity.
ANSWER 4
Answer:
the correct choice would be: 4. Reaction rates are not related to spontaneity.
Explanation:
The speed of reaction is independent of spontaneity, since it depends on other factors such as the amount of reagent.
The amount of reagent is one of the variables that most influences the speed of reaction, the greater the amount of reagent, the faster the reaction will be and thus the speed will be increased.
Identify the following as an example of a physical or chemical. Olive oil, vinegar, salt, and pepper are shaken together together to make salad dressing
Answer:
Chemical Change
Explanation:
Mixing these elements together creates a chemical change
Making of a salad dressing is a physical change as there is no change in the chemical composition.
What is a physical change?
Physical changes are defined as changes which affect only the form of a substance but not it's chemical composition. They are used to separate mixtures in to chemical components but cannot be used to separate compounds to simpler compounds.
Physical changes are always reversible using physical means and involve a change in the physical properties.Examples of physical changes include melting,boiling , change in texture, size,color,volume and density.Magnetism, crystallization, formation of alloys are all reversible and hence physical changes.
They involve only rearrangement of atoms and are often characterized to be changes which are reversible.
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What does the energy hill represent on an energy diagram?
A. The potential energy gained by the products when a reaction
happens
B. The final amount of potential energy of the products of the
reaction
C. The potential energy the reactant's have stored in molecular bonds
D. The additionat potential energy the reactants must gain in order to
React
Answer:
d
Explanation:
its not a b c
what happens when sodium and sulfur combine
Answer:
Sodium sulfide is the chemical compound with the formula Na2S, or more commonly its hydrate Na2S·9H2O. Both the anhydrous and the hydrated salts are colorless solids. They are water-soluble, giving strongly alkaline solutions. When exposed to moist air, Na2S and its hydrates emit hydrogen sulfide, which smells like rotten eggs. Some commercial samples are specified as Na2S·xH2O, where a weight percentage of Na2S is specified. Commonly available grades have around 60% Na2S by weight, which means that x is around 3. Such technical grades of sodium sulfide have a yellow appearance owing to the presence of polysulfides. These grades of sodium sulfide are marketed as 'sodium sulfide flakes'.
Contents
1 Structure
2 Production
3 Reactions with inorganic reagents
4 Uses
4.1 Reagent in organic chemistry
5 Safety
6 References
Structure
Na2S adopts the antifluorite structure,[2][3] which means that the Na+ centers occupy sites of the fluoride in the CaF2 framework, and the larger S2− occupy the sites for Ca2+.
Production
Industrially Na2S is produced by carbothermic reduction of sodium sulfate often using coal:[4]
Na2SO4 + 2 C → Na2S + 2 CO2
In the laboratory, the salt can be prepared by reduction of sulfur with sodium in anhydrous ammonia, or by sodium in dry THF with a catalytic amount of naphthalene (forming sodium naphthalenide):[5]
2 Na + S → Na2S
Reactions with inorganic reagents
The sulfide ion in sulfide salts such as sodium sulfide can incorporate a proton into the salt by protonation:
S2−
+ H+ → SH−
Because of this capture of the proton ( H+), sodium sulfide has basic character. Sodium sulfide is strongly basic, able to absorb two protons. Its conjugate acid is sodium hydrosulfide (SH−
). An aqueous solution contains a significant portion of sulfide ions that are singly protonated.
S2−
+ H
2O {\displaystyle {\ce {<=>>}}}{\displaystyle {\ce {<=>>}}} SH−
+ OH−
(1)
SH−
+ H
2O {\displaystyle {\ce {<<=>}}}{\displaystyle {\ce {<<=>}}} H
2S + OH−
(2)
Sodium sulfide is unstable in the presence of water due to the gradual loss of hydrogen sulfide into the atmosphere.
When heated with oxygen and carbon dioxide, sodium sulfide can oxidize to sodium carbonate and sulfur dioxide:
2 Na2S + 3 O2 + 2 CO
2 → 2 Na2CO3 + 2 SO2
Oxidation with hydrogen peroxide gives sodium sulfate:[6]
Na2S + 4 H2O2 → 4 H
2O + Na2SO4
Upon treatment with sulfur, polysulfides are formed:
2 Na2S + S8 → 2 Na2S5
Uses
Sodium sulfide is primarily used in the kraft process in the pulp and paper industry.
It is used in water treatment as an oxygen scavenger agent and also as a metals precipitant; in chemical photography for toning black and white photographs; in the textile industry as a bleaching agent, for desulfurising and as a dechlorinating agent; and in the leather trade for the sulfitisation of tanning extracts. It is used in chemical manufacturing as a sulfonation and sulfomethylation agent. It is used in the production of rubber chemicals, sulfur dyes and other chemical compounds. It is used in other applications including ore flotation, oil recovery, making dyes, and detergent. It is also used during leather processing, as an unhairing agent in the liming operation.
Reagent in organic chemistry
Alkylation of sodium sulfide give thioethers:
Na2S + 2 RX → R2S + 2 NaX
Even aryl halides participate in this reaction.[7] By a broadly similar process sodium sulfide can react with alkenes in the thiol-ene reaction to give thioethers. Sodium sulfide can be used as nucleophile in Sandmeyer type reactions.[8] Sodium sulfide reduces1,3-dinitrobenzene derivatives to the 3-nitroanilines.[9] Aqueous solution of sodium sulfide can be refluxed with nitro carrying azo dyes dissolved in dioxane and ethanol to selectively reduce the nitro groups to amine; while other reducible groups, e.g. azo group, remain intact.[10] Sulfide has also been employed in photocatalytic applications.[11]
Explanation:there you go
When sodium combines with sulphur, it formed sodium sulphide. When it interacts with sulfur, polysulfides are produced. Additionally, heat causes sodium sulfide to oxidize fast. Sulfur dioxide and sodium carbonate are the end products.
What is sulphur ?Chemical element sulfur has the letter S and atomic number 16. It is multivalent, nonmetallic, and plentiful. Sulfur atoms normally combine to create cyclic octatomic molecules, which have the chemical formula S₈.
At room temperature, elemental sulfur is a crystalline solid that is brilliant yellow. It is employed in the production of fertilizer, water treatment, mineral extraction, oil refining, and automobile batteries.
Other uses for compounds based on sulfur include vulcanizing rubber, bleaching paper, and producing goods like cement, detergents, and insecticides.
Thus, When sodium combines with sulphur, it formed sodium sulphide.
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8. A 50.0 mL 0.05 mol/l solution of sodium cloride (NaCl) was mixed with 100.0 mL
of 0.02 mol/l NaCl solution. What is the mass percent of NaCl in the final solution?
Assume the volumes are additive and their densities 21 g/mL. The molar mass of
NaCl is 58.5 g/mol. (10 points)
Answer:
[tex]\large \boxed{0.012 \%}[/tex]
Explanation:
Data:
Solution 1: V₁ = 50.0 mL; c₁ = 0.05 mol·L⁻¹
Solution 2: V₂ = 100 mL; c₂ = 0.02 mol·L⁻¹
NaCl : ρ = 2.1 g/mL
1. Solution 1
(a) Moles of NaCl
[tex]n = \text{50.0 mL} \times \dfrac{\text{0.05 mmol}}{\text{1 L}} = \text{2.5 mmol}[/tex]
(b) Mass of NaCl
[tex]m = \text{2.5 mmol} \times \dfrac{\text{58.5 mg}}{\text{1 mmol}} = \text{150 mg} = \text{0.15 g}[/tex]
(c) Volume of NaCl
[tex]V = \text{0.15 g} \times \dfrac{\text{1 mL}}{\text{2.1 g}} = \text{0.070 mL}[/tex]
(d) Volume of water
V = 50.0 mL - 0.070 mL = 49.9 mL
(e) Mass of water
[tex]\text{Mass} = \text{49.9 mL} \times \dfrac{\text{1.00g}}{\text{1 mL}} = \text{49.9 g}[/tex]
2. Solution 2
(a) Moles of NaCl
[tex]n = \text{100 mL} \times \dfrac{\text{0.02 mmol}}{\text{1 mL}} = \text{2.0 mmol}[/tex]
(b) Mass of NaCl
[tex]m = \text{2.0 mmol} \times \dfrac{\text{58.5 mg}}{\text{1 mmol}} = \text{120 mg} = \text{0.12 g}[/tex]
(c) Volume of NaCl
[tex]V = \text{0.12 g} \times \dfrac{\text{1 mL}}{\text{2.1 g}} = \text{0.053 mL}[/tex]
(d) Volume of water
V =100 mL - 0.055 mL = 100 mL
(e) Mass of water
[tex]\text{Mass} = \text{100 mL} \times \dfrac{\text{1.00 g}}{\text{1 mL}} = \text{100 g}[/tex]
3. Combined solutions
(a) Mass of NaCl
Mass of NaCl = 0.015 g + 0.012 g = 0.018 g
(b) Mass of water
Mass of water = 49.9 g + 100 g = 150 g
(c) Mass percent
[tex]\text{Mass percent} = \dfrac{\text{Mass of component}}{\text{Total mass}} \times \, 100 \,\%\\\\\text{Mass \% NaCl} = \dfrac{\text{0.018 g}}{\text{150 g}}\times \, 100 \% = \mathbf{0.012 \%}\\\\\text{The mass percent of NaCl is $\large \boxed{\mathbf{0.012 \, \%}}$}[/tex]
Choose the correct answer:
In a galvanic cell:
a- The reactions taking place are non spontaneous
b- The cathode is negative
c- Electrical energy is converted into chemical energy
d- Chemical energy is converted into electrical energy
Answer:
D.
Explanation:
In a Galvanic cell:
1) Spontaneous reactions take place
2) Chemical Energy is converted to some useful electrical energy
This chemical equation is balanced.
F2+ 2NaBr – 2NaF + Br2
How does the balanced chemical equation show the conservation of matter
in this chemical reaction?
O A. The number of Fatoms in the reactants equals the number of F
atoms in the products.
B. There are more Br atoms in the reactants than in the products.
C. There are fewer Na atoms in the reactants than in the products.
D. The compound Naf is a substance that is different from the
compound NaBr
Answer:
A
Explanation:
Zinc will displace copper from a solution of copper sulfate, and magnesium will displace zinc from a solution of zinc sulfate. Why can these displacement reactions be regarded as redox reactions? Write down a series of reactivity for these three metals, putting them in order of increasing reactivity.
Answer:
The displacement reactions are regarded as redox reactions because they involve the formal transfer of electrons from one chemical specie to the other
2) The series of reactivity of the metals in the order of increasing reactivity are;
Copper↓
Zinc↓
MagnesiumExplanation:
1) Redox (oxidation-reduction) reaction is a chemical reaction involving the loss and gain of electrons from one chemical species to another, where the chemical species that undergoes oxidation, loses electrons and is termed the reducing agent, while the other chemical species that undergoes reduction, gains electrons, and is termed the oxidizing agent
2) The redox reaction can being based on the affinity for electrons depends on the positions of the reactants in the electrochemical series as well as the chemical reactivity of the metals with zinc being a stronger reducing agent and more chemically reactive than copper and magnesium being a stronger reducing agent and more chemically reactive than zinc
Least reactive (Cu) < (Zn) < Mg Most reactive
Copper < Zinc < Magnesium.
Mass box A = 10 grams; Mass box B = 5 grams; Mass box C—made of one A and one B
How many boxes of A would be required to make 30 grams of C?
Answer:
the answer would be 2
Explanation:
1. Hummingbirds eat approximately 43.0 g of sugar water per day How many moles of carbon dioxide are released daily by a hummingbird's respiration? C_12H_22O_11 + 12O_2 ------> 12CO_2 + 11H_2O
Answer:
1.507 moles of CO₂ are released daily by a hummingbird's respiration
Explanation:
The reaction of production of carbon dioxide and water from sugar is:
C₁₂H₂₂O₁₁ + 12O₂ → 12CO₂ + 11H₂O
Where 1 mole of sugar produce 12 moles of CO₂
Molar mass of sugar (To convert the mass to moles) is:
12C = 12ₓ12.01g/mol = 144.12g/mol
22H = 22ₓ1.01g/mol = 22.22g/mol
11O = 11ₓ16g/mol = 176g/mol
144.12 + 22.22 + 176 = 342.34g/mol
Thus, moles of 43.0g of sugar are:
43.0g ₓ (1mol / 342.34g) = 0.1256 moles of sugar.
As 1 mole of sugar produce 12 moles of CO₂:
0.1256 moles of sugar ₓ (12 moles CO₂ / 1 mol sugar) =
1.507 moles of CO₂ are released daily by a hummingbird's respiration
Question 28 (2 points)
Which of the following is part of the Kinetic Molecular Theory?
1) gases consist of tiny particles that are close together
2) gas molecules are in constant random motion
3) Il of the above are part of the Kinetic Molecular Theory
4) the average kinetic motion of gas molecules decreases with an increase in
temperature
Marook nie
Answer:
Il of the above are part of the Kinetic Molecular Theory
Explanation:
Answer: Which of the following are part of kinetic-molecular theory?
Choices:
1. The particles in a solid do not move.
2. The particles in a liquid are moving past one another constantly.
3. The particles in gas move freely in all directions.
4. The particles in a solid vibrate in a fixed position.
5. The particles in a solid are far apart.
6. The particles in a gas have few attractions between them.
7. The particles in all states of matter are always moving.
Explanation: Which of the following are part of kinetic-molecular theory...
Answers:
2. The particles in a liquid are moving past one another constantly.
3. The particles in gas move freely in all directions.
4. The particles in a solid vibrate in a fixed position.
6. The particles in a gas have few attractions between them.
7. The particles in all states of matter are always moving.
On many common appliances, there is an “O” or “I” on the power switch. What does each symbol mean?
Pls help asap!!! I don’t understand how to do it
Answer:
split the reaction in to respective ions to ge the ionic equation of this reaction
Explanation:
2 Al + 2Fe+3 O3^-2 ---> 2Al+3 O3^-2 + 2Fe
ins simple it would be
Al + Fe+3 ----> Al+3 + Fe
What did early scientists assume that the polar caps had in common?
Answer:
They assumed they both had water.
Explanation:
Because they only could look at it through telescopes that were not advanced
which gas is used to take out blueprint
Answer:
ammonium ferric citrate and
potassium ferricyanide
Answer:
ammonium ferric citrate and potassium ferricyanide
sperm can be carried by _____ grains. ANSWERSSSSSSSSSSSSSSSSS O spore O stamen O pollen
What is pollen in the reproduction cycle of flowering plants?
A pollen grain is a microspore containing the male gametophyte, usually reduced to two undivided cells, each with one haploid (n) nucleus. These cells are surrounded by a very resistant wall, the exine, which generally has apertures, zones with less resistance which will allow the germination of the pollen tube.
Explanation of the reproduction cycle (cf diagram above)
A given species produces flowers bearing stamens. According to species, these flowers can be unisexual (stamens only) or bisexual (stamens and carpels).
The stamen anthers include 4 pollen sacs containing sporogenous cells (diploid=2n). These sporogenous cells undergo meiosis, each producing 4 microspores (haploid=n). Two nuclei are then formed by mitosis : the vegetative nucleus and the generative nucleus. The latter divides to form 2 sperms. Simultaneously the wall of the microspores becomes thicker and takes the characteristic shape of the species : it is a pollen grain (see: What are the morphological characteristics of pollen and spore grains?). In the majority of species, the 4 grains (resulting from the 4 microspores) split up into single grains; in some cases, they remain together (tetrad = group of 4 grains). When mature, pollen grains are released by the opening of the anthers.
A pollen grain is aimed at reaching another flower of the same species, bearing carpels. The ovaries contain ovules, in which meiosis occurs, then mitoses. It results in an embryo sac with 8 nuclei, among which an egg cell and 2 central cells. When a pollen grain arrives on another flower (see : How are the spores and pollen grains transported?), it is received by the stigmas.
The pollen grain germinates through an opening of the wall: the vegetative nucleus develops into a pollen tube which is guided by the style to the ovary, then enters the micropyle of an ovule. The pollen tube releases 2 sperm nuclei into the ovule: one of the sperms fuses with the egg cell into a zygote (2n), while the other sperm fuses with central nuclei and gives rise to albumen (= food source). There are generally several ovules in an ovary : each one can be fertilized by a distinct pollen grain.
Each fertilized ovule and its albumen form a seed that will develop into a new individual of this species. hope it works
Answer:
pollen
Explanation:
you insolent vacuum
Which answer best describes what is happening in the following redox reaction?
4Fe + 302.
2Fe2O3
Answer:
Iron is oxidized to form rust.
Explanation:
Consider the reaction; 4Fe + 302------>2Fe2O3, we can see that iron is being oxidized to iron III oxide. Rust is the common name of iron III oxide.
Rusting is an electrochemical process, iron rusts when it comes into contact with air and water because electrochemical cells are set up at the surface of contact.
Iron usually functions as the anode in the electrochemical process. This process leads to the formation of iron III oxide. Rust is soft and breaks off easily thereby exposing the metal below the surface to further rusting.
Answer:
Iron is oxidized to form rust.
Explanation:
edge
Which of the following are true of phases?Check all that apply.A.The particles in a liquid are in a fixed location.B.Gases have more kinetic energy than liquids or solids.C.The particles of a solid vibrate.D.Gases have weak intermolecular forces between the atoms or molecules.
Answer:
D. Gases have weak intermolecular forces between them
What is the molecularity of the elementary step A+ B+ C?
O A.
unimolecular
OB.
bimolecular
O C. trimolecular
OD
tetramolecular
Answer:
trimolecular
Explanation:
which of these questions is a scientific question?
A) Are lentils a more enjoyable source of fiber that black beans?
B)Which contains higher level of vitamin B -orange or spinach ?
C)Does asparagus taste better that Brussels sprouts ?
D) Do yellow apples taste better that red apples ?
HELP !!!!!!!!!!!