Answer:
31.24 kJ
Explanation:
SiO₂(g) + 3C(s) → SiC(s) + 2CO(g) ΔH° = 624.7 kJ/molFirst we convert 3.00 grams of SiO₂ to moles, using its molar mass:
3.00 g SiO₂ ÷ 60.08 g/mol = 0.05 molNow we calculate the heat absorbed, using the given ΔH°:
If the complete reaction of 1 mol of SiO₂ absorbs 624.7 kJ, then with 0.05 mol:
0.05 mol * 624.7 kJ/mol = 31.24 kJ of heat would be absorbed.The heat absorbed by 3.00 grams of SiO2 is 31.17 kJ/mol.
The thermochemical equation is;
SiO2(g) + 3C(s) → SiC(s) + 2CO(g) ΔH° = 624.7 kJ/mol
The number of moles of SiO2 = 3.00 g/60.08 g/mol = 0.0499 moles
From the reaction equation;
1 mole of SiO2 absorbs 624.7 kJ/mol
0.0499 moles SiO2 absorbs 0.0499 moles × 624.7 kJ/mol/1 mole
= 31.17 kJ/mol
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Which federal agency makes sure federal wildlife laws are followed?
US Forest Service
US Fish and Wildlife Service
Bureau of Land Management
National Park Service
Answer:
us fish and wildlife service
Explanation:
the 2nd choice
Answer:
US Fish and Wildlife Service
i really need help with this
Answer:
the process shown here is endocytosis.
Explanation:
endocytosis is a process of taking something inside the cell..
Which of the following is a property of a non-metal.
luster
ductile
malleable
does not conduct heat and electricity
Answer:
luster
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How does the chemical formula for the sulfite ion differ from the chemical formula for the sulfate ion?
O sulfite contains 2 oxygens and sulfate contains 3 oxygens
O sulfite contains 3 oxygens and sulfate contains 2 oxygens
O sulfite contains 3 oxygens and sulfate contains 4 oxygens
O sulfite contains 4 oxygens and sulfate contains 3 oxygens
Answer:
Sulfite contains 3 oxygens and sulfate contains 4 oxygens
Explanation:
Choose the aqueous solution below with the highest boiling point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.
A) 0.075 m NaI
B) 0.075 m (NH4)3PO4
C) 0.075 m NaBrO4
D) 0.075 m LiCN
E) 0.075 m KNO2
Answer:
B. (NH₄)₃PO₄
Explanation:
Elevation of boiling point is one of the colligative properties.
Formula is: ΔT = Kb . m . i
ΔT = Boiling T° of solution - Boiling T° of pure solvent.
i = Van't Hoff factor (numbers of ions dissolved)
Kb = Ebulloscopic constant
In this case, all the m are the same so let's dissociate the salts:
NaI → Na⁺ + I⁻ i = 2
(NH₄)₃PO₄ → 3NH₄⁺ + PO₄⁻³ i = 4
NaBrO₄ → Na⁺ + BrO₄⁻ i = 2
LiCN → Li⁺ + CN⁻ i = 2
KNO2 → K⁺ + NO₂⁻ i = 2
The biggest i would have the biggest boiling point, then B is the right answer, ammonium phosphate.
You count the i, with the moles of ions, you dissociate from the salt.
What are the effects of colonialism on Africa today?
Colonialism made African colonies dependent by introducing a mono- cultural economy for the territories. It also dehumanized African labour force and traders. It forced Africans to work in colonial plantations at very low wages and displaced them from their land
What feature of the sun changes to create the solar cycle?
a
Brightness
Hydrogen gas
Nuclear fusion
Magnetic field
What is evolution?
1. Quick change in an organism to eat better
2. A change in the environment
3. Gradual change in the environment due to global warming
4. Gradual change of a species to be better suited for the environment
Answer:
The correct answer is option 4.
Answer:
4 Gradual change of a species to be better suited for the environment
Explanation:
Question 8
Which one of the following salts does not contain water of crystallisation?
Answer:
pb
Explanation:
dosn't contain water of crystallization
5.
Given: C2H5C1
P1: 951.72 kPa
P2: 362.29 kPa
T1: 653.34 K
Wanted: kelvins?
Answer: The final temperature is 248.7 K
Explanation:
To calculate the final temperature of the system, we use the equation given by Gay lussac Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant volume.
Mathematically,
[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]
where,
[tex]P_1\text{ and }T_1[/tex] are the initial pressure and temperature of the gas.
[tex]P_2\text{ and }T_2[/tex] are the final pressure and temperature of the gas.
We are given:
[tex]P_1=951.72kPa\\T_1=653.34K\\P_2=362.29kPa\\T_2=?[/tex]
Putting values in above equation, we get:
[tex]\frac{951.72}{653.34}=\frac{362.29}{T_2}\\\\T_2=248.7K[/tex]
Thus the final temperature is 248.7 K
If the molecular mass of a substance is 7.304 • 10²³ g, find its molar mass.
Answer:
1.213 g/mol
Explanation:
We are given that the molecular mass is 7.304 × 10²³ g.
From avogadro's number, we know that;
1 mole of a substance = 6.022 × 10²³ molecules
Thus;
Molar mass = molecular mass/avogadro's number = (7.304 × 10²³)/(6.022 × 10²³) = 1.213 g/mol
Why is sterilising the water rarely used in treating the sewage water?
Answer:
Sterilizing the water rarely used in treating the sewage water is described below in details.
Explanation:
Sterilization is the application of a chemical or physical system to eradicate all microorganisms, concluding comprehensive amounts of bacterial content. Heat treatment is the most relevant approach for the sterilization of waste-water that accommodates large levels of masses. well now sterilizing the water is un-usually practiced in managing the sewage water.
What mass of MnCl2 is produced when 0.091 g of Cl2 is generated?
The mass of MnCl2 that is produced when 0.091 g of Cl2 is generated is 0.16 g.
Molar mass of MnCl₂ = 55 + 35.5(2) = 126 g/mol
Molar mass of Cl₂ = 35.5(2) = 71 g/mol
If 71 g of Cl₂ gives 126 g of MnCl₂
0.091 g of Cl₂ will give ? of MnCl₂
cross multiply
mass of MnCl₂ produced = 0.091 × 126 / 71
mass of MnCl₂ produced = 11.466 / 71
mass of MnCl₂ produced = 0.16149295774
mass of MnCl₂ produced ≈ 0.16 g
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explain why a nanowire can be longer than 3000nm but still be considered a metallic nanomaterial
Answer:
A nanowire is a nanostructure, with the diameter of the order of a nanometre (10−9 meters). It can also be defined as the ratio of the length to width being greater than 1000. Alternatively, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. At these scales, quantum mechanical effects are important—which coined the term "quantum wires". Many different types of nanowires exist, including superconducting (e.g. YBCO[1]), metallic (e.g. Ni, Pt, Au, Ag), semiconducting (e.g. silicon nanowires (SiNWs), InP, GaN) and insulating (e.g. SiO2, TiO2). Molecular nanowires are composed of repeating molecular units either organic (e.g. DNA) or inorganic (e.g. Mo6S9−xIx).
Explanation:
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What is true of experimental designs that are used in scientific research? The designs use the same steps in every kind of research. The designs follow a general method that is familiar to all scientists. The designs ensure that the experimental data supports the hypothesis. The designs are kept secret so that others must do their own experiments.. The answer is B.) "The designs follow a general method that is familiar to all scientists."
Answer:
The designs ensure that the experimental.
Explanation:
Scientific research refers to the-fact finding inquiry to answer the questions related to natural processes. A hypothesis is a situation or an assumption that needs to be proved by applying scientific produces. Experimental design refers to the methodology, which is applied to conduct research.
The designs ensure that the experimental data support the hypothesis is the true statement regarding experimental designs that are used in scientific research because an experimental design should be concerned with the fact that it is relevant or appropriate to prove a hypothesis.
Answer:
its c. the designs follow a general method that is familiar to all scientists
Explanation:
Help me with this please
= 0.2+560.66JK-2eF
use this app : Photomath
It will help you :)
Our current model of a chemical bond is to think of it as an electrical interaction between what two parts of an atom
Answer:
Explanation:
It involves the thinking of it as an electrical interaction between the positively charged part of an atom and the negatively charged part as well. Succinctly put, the interaction between the proton of an atom and the electron of an atom.
The relationship between these two sub atomic particles is one of the basis for many chemical bonding, and this is inclusive of all the bonds there exist. Hydrogen, Electrovalent and even Covalent bondings to mention but a few
Calculate the standard enthalpy of reaction
for the reaction 2 Na (s) + 2 H₂O (l)
2 NaOH (aq) + H₂ (g), Standard enthalpies
formation are -285.8 kJ/mol for H₂O and -470. 11 kJ/mol for NaOH (aq).
Answer:
-368.62 kJ/mol
Explanation:
[(2 x - 470.11 kJ/mol) ( 0kJ/mol)] - [ 2 x -285.8 kJ/mol) (2x 0 kj/mol)] = -368.62 kJ/mol
Periodic law states that elements show a
A. repetition of their physical and chemical properties when arranged according to increased atomic number
B. repetition of their physical and chemical properties when arranged according to increased atomic mass
C. repetition of their physical and chemical properties when arranged according to increased atomic size
D. repetition of their physical and chemical properties when arranged according to increased atomic radius
Answer:
A. repetition of their physical and chemical properties when arranged according to increased atomic number
Explanation:
There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Therefore, option A is correct option.
What is periodic table?Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.
Periodic table help a scientist to know what are the different types of elements are present in periodic table so that they can discover the new elements that are not being discovered yet.
Periodic law states that elements show a repetition of their physical and chemical properties when arranged according to increased atomic number.
Therefore, the correct option is option A out of given options.
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The relative humidity is 100%, and the temperature is hot. In a few sentences, explain how the weather would change if the temperature drops and becomes cool.
Answer:
Humdity would decrease hence temprature would do the same, hence tundra are called deserts at times.
Explanation:
If you keep on decreasing the temperature without changing the air's moisture content significantly, eventually you'll reach 100 percent relative humidity, and then water vapor will start to condense to form dew.
What happens when humidity is at 100% and the temperature drops?Dew Point. When the relative humidity reaches 100 percent, dew forms. Dew point refers to the temperature at which air reaches saturation by water molecules. Warmer air can hold more water molecules, and as that warm air cools, it loses water vapor in the form of condensation.
What happens when it reaches 100% relative humidity?When relative humidity reaches 100 percent or is saturated, moisture will condense, meaning the water vapor changes to liquid-vapor. Thus, the saturation level of air is related to the air's temperature.
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What is the formula for triboron silicide?
Answer:
B₃Si
Explanation:
Let's take break it down. From triboron silicide;
Tri - Three
Triboron - Three boron atoms
Silicide - Silicon (with an -ide suffix)
The formular is given as;
B₃Si
At what power of ten does the entire solar system come into view
Answer: 10,000,000,000 kilometers
Explanation:
All the planets in our solar system come into view. But at this distance, only Jupiter and Saturn would be visible with the naked eye.
Find the amount of water containing 14.02 * 10²⁴ molecules
Answer:
14.02 x 10²⁴ molecules
Explanation:
To solve this problem we will use Avogadro's number: It relates to the number of molecules (or atoms) contained in 1 mol of any given substance:
14.02 x 10²⁴ molecules ÷ 6.023 x 10²³ molecules/mol = 23.28 molesThus, 23.28 moles of water contain 14.02 x 10²⁴ molecules.
1s2, 2s2, 2p6, 3s2, 3p6, 4s2
After this atom gains or loses valence electron/s, what will the oxidation number be?
Answer:
if it gains then it will be negative to whatever number it has gained and the reverse for when it loses
Explanation:
how many atoms are in 1.2x10^5 moles of neon?
Answer:
7.224 × 10^28 atoms
Explanation:
The number of moles contained in a substance (n) can be calculated from this expression:
nA = n × 6.02 × 10^23 atoms
Where;
nA = number of atoms of substance
n = number of moles of substance
Avagadro's number or constant = 6.02 × 10^23 atoms
Using nA = n × 6.02 × 10^23 atoms
In this question, there are 1.2 x 10^5 moles of neon (N). The number of atoms (nA) is as follows:
nA of neon = 1.2 x 10^5 × 6.02 × 10^23
nA = 7.224 × 10^ (5 + 23)
nA = 7.224 × 10^28 atoms
The number of neon atoms in 1.2 x 10^5 is 7.224 × 10^28 atoms.
why are gases able to spread out and fill whatever container they are in
Answer:
gases are able to spread out and fill whatever container they are in because they do not have. a definite shape their molecules are not tightly packed so they can cover over a vast area like our atmosphere.
Table sugar and salt are examples of? A. mixtures B. elements C. atoms D. compounds
Answer:
The answer is compound because they consist of multiple things.
2NaCl → 2Na +Cl2
What reaction is this
Answer:
Decomposition reaction
Explanation:
A single reactant breaking down to form 2 or more products is decomposition
Can someone help me ASAP.
Answer:
This type of mutation occurs when one or more base pairs are added to the gene sequence: insertion
This type of mutation occurs when one or more base pairs take the place of other base pairs in the gene sequence: substitution
Where is the youngest rock in the Atlantic Ocean found?
plz hurry
Answer:
Seafloor Ages
They found that the youngest rocks on the seafloor were at the mid-ocean ridges. The rocks get older with distance from the ridge crest.
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