Será lançado na próxima quarta-feira, 1º de julho, em São Bernardo do Campo (SP), o primeiro ônibus brasileiro a hidrogênio. [...] O projeto Ônibus Brasileiro à Célula Combustível a Hidrogênio é o ponto de partida para o desenvolvimento de uma solução mais limpa para o transporte público urbano no Brasil. (Disponível em: Acesso em: 19 out. 2009.) Quanto aos processos químicos envolvidos na produção de energia elétrica em células de combustíveis a partir do oxigênio e do hidrogênio, é correto afirmar:
Give 264.2g of (NH4)2SO4, calculate the
a) amount of (NH4)2SO4
b) number of ions
c) number of atoms
d) number of H atoms
e) number of N atoms
With workings please! Thanks so much!
Answer:
D.
Explanation:
Thank me later
#modulepamoreitsreallyhurts
#modulelangsakalam
#moduleisreallyhurts
which metals or non-metals are liquid at a room temperature of 25°C?
Answer:
gallium
Explanation:
it is the old melting in a hot cup of coffee spoon
Answer:
Elements That Are Liquid at 25°C
•Bromine
•mercury
Explanation:
The metal which exist as a liquid at room temperature is mercury.
Non-metal which exist as a liquid at room temperature is bromine.
was this answer helpful?
yes or no?
if yes give like
thankyou
The answer to this question is D as it says in the answer sheet of the question paper but how?
Answer:
D
Explanation:
Because of their complementary nature, the oxidation and reduction processes together are referred to as redox reactions. The reactant that brings about the oxidation is called the oxidizing agent, and that reagent is itself reduced by the reducing agent. Examples are, mercury(II) oxide, oxygen, and the copper(II) ion are oxidizing agents, and carbon, hydrazine, and zinc are the reducing agents.
Answer:D
Explanation:Because of their complementary nature, the oxidation and reduction processes together are referred to as redox reactions. The reactant that brings about the oxidation is called the oxidizing agent, and that reagent is itself reduced by the reducing agent. Examples are, mercury(II) oxide, oxygen, and the copper(II) ion are oxidizing agents, and carbon, hydrazine, and zinc are the reducing agents.
Calculate the heat energy, in kJ, needed to increase the temperature of 375g of water by 45.0°C.
Explanation:
https://socratic.org/questions/how-much-heat-kj-is-needed-to-raise-the-temperature-of-100-0-grams-of-water-from#216827
Determine if the following two structures are
identical, isomers, or unrelated?
Answer:
its C........................
The following two structures are Isomers.
What are isomers and examples?
Isomers are compounds that contain exactly the same number of atoms, i.e., they have exactly the same empirical formula, but differ from each other by the way in which the atoms are arranged. Examples of isomers with the formula C8H10 are ethyl benzene, m-xylene, p-xylene, and o-xylene.
What are the 3 types of isomers?
There are three types of structural isomers: chain isomers, functional group isomers, and positional isomers.
What are isomers in biology?
Isomers are molecules with the same chemical formula but have different structures. Isomers differ in how their bonds are positioned to surrounding atoms.
Learn more about Isomers in biology at https://brainly.com/question/18474884
#SPJ2
Which element has a smaller ionic radius than magnesium (Mg)?
A) Rb
B) Al
C) Ca
D) Na
Answer:
Na has atomic number 11
which is less than magnesium has atomic number 12
ANSWER IS D
Explanation:
aluminum or Al is atomic 13 and Ca or calcium is atomic number 20 and rubidium or Rb is atomic number 37
What effect does the pH of water have on radish seed germination?
Answer:
High pH negatively affected the germination rate of seeds from most species, but had no effect on the per cent germination of any of the species. The higher concentration of the nutritious solutions affected negatively the germination level and rate
Explanation:
32. Calculate the pH of a solution at 1.00 x 10- MIH") and identify the substance as an acid or base,
Answer:
[tex]{ \boxed{ \tt{formular : pH = - log[H {}^{ + } ]}}} \\ pH = - log(1.00 \times {10}^{-6} ) = 6: it's an acid\\ since \: we \: lack \: the \: exponent, \: this \: question \: is \: unsolvable \\ { \green{ \bf{take \: note}}} :{ \tt{pH \: below \: 7 \: that \: is \: { \red{acidic}}. \: \: pH \: greater \: than \: 7 \: is \: { \red {basic}}}}[/tex]
There are on average 43 g of sugar and 355 mL can of soda please calculate the molarity of sugar in the can of soda the molar mass of sugar is 342.2 g/mol
Explanation:
Given :
Amount of solute - sucrose (C12H22O11) = 41 g
Amount of solvent -soda = 355-mL
Molarity of the solution with respect to sucrose= ?
Molarity(M) is a unit of concentration measuring the number of moles of a solute per liter of solution. The SI unit of molarity is mol/L.
Formula to find the molarity of solution :
Molarity =
Amount of solvent is given in mL, let’s convert to L :
1 L = 1000 mL
Therefore, 355 mL in L will be :
= 0.355 L
We have the amount of solute in g, let’s calculate the number of moles first :
Number of moles (n) =
Molar mass of C12H22O11 = 342.29 g/mol.
Therefore, n =
= 0.119 moles.
8. In a chemical reaction, if the reactants are heated, the reaction usually
happens a) Faster
b) Slower
c) At the same rate
the reaction usually happens faster
Difference between
Atom and molecule
Answer:
Atoms are single neutral particles. Molecules are neutral particles made of two or more atoms bonded together.
Explanation:
its on safari ??????????
What happens when phenol is treated with bromine water?
Answer:
Polyhalogen derivatives are given when Phenol is treated with bromine water, in which all the H-atoms present at the o- and p- positions are substituted by Bromine with respect to the -OH group.
hope it helps
thanku
Explanation:
Explain and describe how the photoelectric effect occurs on an atomic level in terms of protons, neutrons, and electrons
ANSWER:
Explaining the experiments on the photoelectric effect. How these experiments led to the idea if light behaving as a particle of energy called a photon.
What is the molarity of 4 mol of NaOH dissolved in 2 L of water? O A. 0.5 M OB. 8 M O C. 2M D. 4 M
Answer:
concentration = mol/volume = 4/2 = 2M
Explain why, when a force is applied to a piece of steel, it does not break but just
changes its shape.
Steel is a metal. Metals atoms are able to roll over each other into new positions without breaking the metallic bond. So, steel doesn't break but changes its shape.
KHP, the acid used in this experiment,
stands for potassium hydrogen
phosphorous.
True
False
Answer:
false
Explanation:
standard form is Potassium hydrogen phthalate
Which of the following increases the ratio?
Both β+ and β– decay
Only β– decay
Neither β+ nor β– decay
Only β+ decay
Answer:
Only β+ decay
Explanation:
In positron emission, a proton is converted into a neutron and a positron. An anti neutrino is a particle that serves the purpose of balancing the spins.
During positron emission, the mass number to the daughter nucleus is the same as that of the parent nucleus but the atomic number of the daughter nucleus is less than that of the parent nucleus by one unit.
Positron emission increases the neutron/proton ratio.
Subtract to find the temperature changes
for the water and the metal.
Answer:
???what metal????????????
Which statements are correct regarding the Law of Conservation of Matter and Energy?
Matter or energy can create itself.
Matter or energy was created by known principles of physics and chemistry.
Matter or energy can change from one form to the other.
The law agrees with the Biblical account of Creation
(more than one answer)
Answer:
Matter or energy can change from one form to the other
Explanation:
The law of conservation of energy states that energy can neither be created nor destroyed but can only be transformed i.e. changed from one form to another. For example, mechanical energy can be changed to electrical energy.
Likewise, the law of conservation of mass/matter states that matter can not be destroyed or created but can change via physical or chemical means to conserve it. For example, matter can change from liquid state to gaseous state.
From the above two laws, it can be said that "matter or energy can change from one form to the other".
PLEASE HELP!!!
The options are:
A. Nitrogen.
B. Neon.
C. Hydrogen chloride.
D. Sulfur dioxide.
Answer:
Hydrogen Chloride
Explanation:
They will be able to dissolve quicker than the rest
Answer:
C. Hydrogen chloride.
Explanation:
Hydrogen chloride gas will diffuse most quickly.
Hope it is helpful....Which question would most likely be studied by a physicist?
A.
Were there ever any living organisms on Mars?
B.
Should the government spend taxpayers' money to send space probes to Mars?
C.
How can the forces on a space probe be controlled so it will land on Mars?
D.
What type of substances make up the soil on Mars?
Answer:
C.
Explanation:
Physicists main field of study is physics. This includes everything from force, matter, energy, and even time among other things. Therefore, from the questions provided the one that would most likely be studied by a physicist would be How can the forces on a space probe be controlled so it will land on Mars? This is because this question deals with forces acting on an object, regardless of what the object is Force is a huge part of physics and therefore studied by Physicists.
help please I would really appreciate
Answer:
option C
Positive terminal of the cell connected with redExplanation:
hope it may help you
two reactants to produce sodium carbonate salt?
Answer: equivalent amounts of sodium hydroxide and a solution of sodium hydrogen carbonate
Explanation:
chemical symbol for an atom of lithium
Answer:
Li
Explanation:
It's on the periodic table.
EXAMPLES OF PURE SUBSTANCES
Answer: Water, tin, sulfur, sucrose, salt, and etc.
Explanation: The photo has more examples
How does chemistry affect sports?
What properties can be used to identify substance and why?
Answer:
All substances can be characterized by their unique sets of physical and chemical properties. Properties that can be determined without changing the composition of a substance are referred to as physical properties. Characteristics such as melting point, boiling point, density, solubility, color, odor, etc.
Jonathan conducts an experiment to determine what solutes readily dissolve in water. He places 3 tablespoons of potting soil into one cup of water. He records his observations in 15-minute increments. After a half hour, he notices that some of the soil particles have separated and sank to the bottom. O 15 minutes 30 minutes Which term best describes the combination of soil and water?
A.Mixture
B. A solution
C. an alloy
D. an emulsion
Answer:
A. Mixture
Explanation:
Which reaction will most likely take place based on the activity series? Li > K Ba CaNa > Mn > Zn > Cr> Fe> Cd Ni > H > Sb > Cu > Ag > Pd > Hg > Pt a. Ag+FeCl 3 b, Zn + CaO C. Ba+Na 2 CO 3 d . Cr+KNO3
Answer:
Among the given reactions,
a. Ag+FeCl 3
b, Zn + CaO
C. Ba+Na 2 CO 3
d . Cr+KNO3
which reaction is likely to take place based on the reactivity series?
Explanation:
The metal reactivity series is:
Li > K> Ba >Ca>Na > Mn > Zn > Cr> Fe> Cd Ni > H > Sb > Cu > Ag > Pd > Hg > Pt
The highly reactive metal will displace the less reactive metal from its compound during a displacement reaction.
a. Ag+FeCl 3
Ag is less reactive than Fe, so Ag cannot displace Fe from its compound.
This reaction also does not occur.
b, Zn + CaO
Zn is less reactive than Ca, so it cannot displace Ca from its compound.
This reaction does not occur.
C. Ba+Na 2 CO 3
Ba is more reactive than Na, so Ba displaces Na from its compound.
This reaction is possible.
d . Cr+KNO3
Cr is less reactive than K, so it cannot displace K from its compound.
Hence, This reaction is not possible.
Answer:
option c) Ba+Na 2 CO 3 -> BaCO3 +2Na
Answer:
C. Ba+Na 2 CO 3 -> BaCO3 +2Na