A fuel cell require a continuous input of fuel and an oxidizing agent in order to sustain the reactions which generate the electricity. The item in which fuel cells more commonly used is propane lanterns. The correct option is D.
What is propane lanterns?The propane lanterns is one of the gas interns which is a lightweight portable device which supplies bright efficient light while protecting its contents from wind and brain. The gas interns are incandescent lights.
The gas interns burn fuel like propane, white gas or kerosene to generate heat and the heat causes the mantles to produce light. The mantles are defined as the ceramic mesh which encase the flame produced by the lantern.
The gas lanterns are very simple, any heated material will produce light. The lantern burns fuel to produce heat. The gas lanterns use mantles instead of limestone blocks. The mantles are highly efficient at producing light from the heat they acquire.
Thus the correct option is D.
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Suppose you have 28.9 grams of elemental germanium, what mass would be the isotope germanium - 72?
34.5 grams
because the mass would multiply and do mass things
What is one of the functions of the nucleus?
A.
to remove waste products from a cell
B.
to contain the genetic information of an organism
C.
to determine what materials can enter or leave a cell
D.
to provide structural support for a plant cell
Answer:
B.
to contain the genetic information of an organism
Explanation:
The nucleus controls and regulates the activities of the cell (e.g., growth and metabolism) and carries the genes, structures that contain the hereditary information. Nucleoli are small bodies often seen within the nucleus.
which statement describes the movement of carbon dioxide in the carbon cycle?
A. The gas leaves the biosphere as animals breathe in air.
B. The gas leaves the atmosphere as plants use it to make sugar.
C. The gas enters the cryosphere as ice sheets melt.
D. The gas enters the hydrosphere as sugar dissolves in water.
Answer:
C. The gas enters the cryosphere as ice sheets
Answer:
D
Explanation:
What is the balanced equation for the reaction of a solution of sodium sulfate is mixed with strontium chloride?
Select one:
a.Na2SO4(aq) + SrCl2(aq) = 2 NaCl(aq) + SrSO4(s)
b.Na2SO4(aq) + SrCl2(aq) = NaCl(s) + SrSO4(aq)
c.NaSO4(aq) + SrCl(aq) = NaCl(aq) + SrSO4(aq)
d.NaSO4(aq) + SrCl(aq) = NaCl(aq) + Sr2SO4(aq)
Answer:A
Explanation: reactants: Na2SO4 and SrCl2
Products: NaCl and SrSO4
What is the number of electronsin hydrogen?
Answer:
1
Explanation:
the relative atomic mass of hydrogen is Ar (H) = 1008.Calculate the absolute mass of a hydrogen atom
Answer:
im good but mark brainliest
Explanation:
Answer:
i don think thats what she ment
Explanation:
These are the last two questions on the sheet I need help with haha, help only the ones you can! (most helpful answer will get brainliest)
Answer:
the 7 question answer is c the 24 question answer is b
Explanation:
What involves a metal and nonmetal ionic or covalent bond
Answer:
An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal. A covalent bond involves a pair of electrons being shared between atoms.
In the modern periodic table, which of the following represents the last pair of elects for which Newlands' Law of Octaves would hold true?
1. AI and GA
2. AI and SI
3. NE and AR
4. MG and CA
Answer: Mg and Ca
Explanation:
In the modern periodic table, Mg and Ca are the last pair of elects for which Newlands' Law of Octaves would hold true.
Law of Octaves is the generalization that was made by Newlands. It states that when chemical elements are arranged based on their increasing atomic weight, then the ones that have the same chemical and physical properties will occur after an interval of seven elements.
In such a case, every eighth element will have identical properties when the elements in the periodic table are arranged based on their atomic masses.
Based on the above information, Magnesium (Mg) has an atomic number of 12 while Calcium (Ca) has an atomic number of 20. Therefore, the elements follow the law of Octaves as they have a difference of 8 in their atomic numbers.
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whats the number of moles of O2(g) needed to completely react with 8 moles of CO(g).
Based on the fossil records, what is true
concerning populations of organisms that lived on
Earth?
A. Most organisms are found in the earliest rock
layers.
B. Most organisms stayed the same over time.
C.
Most organisms that lived on Earth are
extinct.
Helpppppp
Answer:
C
Explanation:
The reason why is beacause most of the dino's and other spices that were here before humanity are exctinct. Some are still alive and have evovled into something greater such as a crocidile, and many other repitlians
Hope this helps!
Pls mark brainlest!
state the difference between isotopes and isobars
Answer:
Isotopes:- these are those elements in which atoms are same but mass number is different. for eg:- 12^C 6.____________________________________________________________________________
Isobars:- these are those elements in which mass number is same but atoms are different. for example:- 2^Ca 18.did scientists accept wegeners theory? why or why not?
Answer:
No, scientists did not accept Wegener's theory
Explanation:
In a book titled; "The Origin of Continents and Oceans", published in 1915, Wegener introduced his ideas about the theory of continental drift.
According to his idea, "all the continents were once joined together in an "Urkontinent" before breaking up and drifting to their current positions"(live science).
Though some of his ideas were correct, some of them were also quite wrong. Scientists rejected his idea because he did not detail any mechanism by which the continental drift occurs.
14.
Consider the following balanced chemical equation:
P205
3 H2O → 2 H3PO4
Calculate the mass of hydrogen phosphate, H3PO, that will be produced from 105.9 g of P,Os.
Answer:
Mass = 72.52 g
Explanation:
Given data:
Mass of hydrogen phosphate produced = ?
Mass of P₂O₅ react = 105.9 g
Solution:
Chemical equation:
P₂O₅ + 3H₂O → 2H₃PO₄
Number of moles of P₂O₅:
Number of moles = mass/molar mass
Molar mass of P₂O₅ 283.9 g/mol
Number of moles = 105.9 g/ 283.9 g/mol
Number of moles = 0.37 mol
Now we will compare the moles of P₂O₅ with H₃PO₄ from balance chemical equation.
P₂O₅ : H₃PO₄
1 : 2
0.37 : 2/1×0.37= 0.74 mol
Mass of H₃PO₄ :
Mass = number of moles × molar mass
Mass = 0.74 mol × 98 g/mol
Mass = 72.52 g
Which of the following statements is/are correct?
I.
II.
Mass of 1 atom of Carbon-12 is equal to 1 amu
Mass of 4 atoms of Carbon-12 is equal to mass of 3 atoms of Oxygen-16
(A) Only I
(B) Only II
(C) Both I and II
(D) None of them
Answer:
The correct statement is;
(B) Only II
Explanation:
I) The atomic mass unit or amu which is also known as daltons which is defined as 1/12 × the mass of a carbon-12 atom, which is therefore, 1.660538921 × ⁻²⁴ grams
Therefore, the mass of 1 atom of carbon-12 = 12 amu
II) The mass of one mole of oxygen-16 is 16 grams while the mass of one mole of carbon-12 is 12 grams
The mass of 4 atoms of carbon 12 = 4 × 12 amu = 48 amu
The mass of 1 atom of oxygen-16 = 15.99491461956 amu
Therefore, the mass of 3 atoms of oxygen-16 = 3 × 15.99491461956 = 47.9847438587 amu ≈ 48 amu
Therefore only II is correct.
PLEASE help due in 25 minutes
Determine the mass in grams of each of the following:
5.04 x 1024 atoms N
2.01 x 1024 atoms Ca
8.32 x 1021 atoms Sn
Determine the number of particles contained in each of the following:
50.3 g Cu
145g Si
0.67 g Cl
Answer:
method to do this given in explaination
Explanation:
divide the number of atoms with avagadro constant and multiply with the molar mass of each atom - to obtain the mass in g
divide the mass with molar mass and multiply with avagadro constant to obtain the number of particles
How can a conceptual model be used to develop a testable hypothesis? Select one: a. Conceptual models cannot be used to develop a testable hypothesis. b. Conceptual models help us see how things are related and how they connect or work together. This helps us develop a hypothesis based on changes in a variable and the corresponding response of another variable. c. Conceptual models are never revised once they are made. d. Conceptual models are not based prior observations and are guesses used to generate a hypothesis.
Answer:
b. Conceptual models help us see how things are related and how they connect or work together. This helps us develop a hypothesis based on changes in a variable and the corresponding response of another variable.
Explanation:
A conceptual model refers to a vivid representation or conceptualization of the working of a system. Hence conceptual models offer explanations to ideas about systems.
They help to fit all the facts together so that one can make sense of a system. Also, it helps us to understand how changes in one variable affects the other in a system, thereby helping us to formulate a testable hypothesis.
how many moles are in 3.00x 10^22 atoms of He?
Answer:
0.05 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{3.0 \times {10}^{22} }{6.02 \times {10}^{23} } \\ = 0.049833...[/tex]
We have the final answer as
0.05 molesHope this helps you
If Veronica spins in a circle with the compass in her hand, which force keeps the compass' needle pointing north?
A.
an electrical force
B.
a magnetic force
C.
a contact force
D.
a gravitational force
If Veronica spins in a circle with the compass in her hand, then the force which keeps the compass' needle pointing north is magnetic field.
What is magnetic force?The magnetic influence on moving electric charges, electric currents, and magnetic materials is described by a magnetic field, which is a vector field. In a magnetic field, a moving charge receives a force that is perpendicular to both its velocity and the magnetic field.
The magnetic field is defined as a region where the force is active along imaginary lines. This force has an effect on all magnetized objects from the south magnetic pole to the north magnetic pole, including the needle of a compass. The needle always points north magnetic pole under the influence of the Geomagnetic field.Hence the required force is a magnetic force.
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Do the molecules of a liquid have (more, less, or the same) freedom of movement as the molecules of a gas? *
help pls help URGENT
Answer:
I think you got it right witth g
Explanation:
is sugar made of tiny particles
which of the following is an acid?
starch in water
sugar in water
toothpaste in water
vinegar
bleach
1. When a liquid becomes vapor, its gas particles begin to exert...
a. air pressure.
c. vapor pressure.
b. equilibrium pressure.
d. no pressure
Answer:
vapor pressure.
Explanation:
Answer:
I think it is vapor pressure or air pressure
Which of the following characterizes a covalent bond?
A. An electronegativity of greater than 1.7 for one of the atoms
B. An electronegativity difference of greater than 1.7 between two
atoms
C. An electronegativity difference of less than 1.7 between two
atoms
D. An electronegativity of less than 1.7 for one of the atoms
Answer A. The electronegativity of one atom is less than 1.7
Answer: its C
Explanation: i just got it wrong the right answer is c
2. What are the ions present in the compound CsF? *
(1 Point)
O Cs- and F-
Cs- and F+
Cs+ and F-
Cs and F only
Answer:
Cs+ and F-
Explanation:
The compound CsF is made up of two elements; Caesium (Cs) and F (Flourine)
Caesium is a metal and would therefore lose electrons - a cation is formed. When Caesium loses a single electron, the ion symbol is given as; Cs+
Flourine is a non metal and would therefore gain electrons - an anion is formed. When Flourine gains a single electron, the ion symbol is given as; F-
Hence the correct option is;
Cs+ and F-
Which term describes this reaction?
addition
condensation
elimination
substitution
Addition is the answer
What is the overall process of balancing an equation?
Answer:
You need to make sure the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side. In order make both sides equal, you will need to multiply the number of atoms in each element until both sides are equal. :)
1. Freon (CCl2F2) is commonly used in refrigerators and air conditioners as a coolant. How many grams of fluorine are there in the 2.00 lbs of Freon necessary for an air conditioner? (1 lb = 454 g)
Answer:
285g of fluorine
Explanation:
To solve this problem we need to find the mass of Freon in grams. Then, with its molar mass we can find moles of freon and, as 1 mole of Freon, CCl₂F₂, contains 2 moles of fluorine, we can find moles of fluorine and its mass:
Mass Freon:
2.00lbs * (454g / 1lb) = 908g of Freon
Moles freon -Molar mass: 120.91g/mol- and moles of fluorine:
908g of Freon * (1mol / 120.91g) =
7.5 moles of freon * (2moles Fluorine / mole Freon): 15 moles of fluorine
Mass fluorine -Atomic mass: 19g/mol-:
15 moles F * (19g / mol) =
285g of fluorineBohr models show _________ while Dot Diagrams show _______ electrons only.
Answer:
Bohr models show the electrons in atoms are in orbits of differing energy around the nucleus while Dot Diagrams show the bonding in a small molecule only.
Explanation: