Answer:
2.49moles
Explanation:
To calculate the number of moles (n), of iron (Fe) in 1.5 × 10²⁴ atoms, we divide the number of atoms by Avogadro's number (6.02 × 10²³).
That is, n = N ÷ nA
Where;
n = number of moles (mol)
N = number of atoms
nA = Avogadro's constant
n = 1.5 × 10²⁴ ÷ 6.02 × 10²³
n = 1.5/6.02 × 10(²⁴ - ²³)
n = 0.249 × 10¹
n = 2.49moles
Which of the following is true of a reaction with a negative enthalpy?
O A. The enthalpy of the reactants is greater than that of the products.
B. The reaction has a negative activation energy.
C. The enthalpies of the products and reactants are both negative.
D. The enthalpy of the reactants is less than that of the products.
Answer: The statement enthalpy of the reactants is greater than that of the products is true of a reaction with a negative enthalpy.
Explanation:
A chemical reaction where energy is being released is called an exothermic reaction.
In an exothermic reaction, the value of enthalpy of reaction is negative in nature.
Also, heat is being released which means the reactants has more energy than the products due to which the value of enthalpy is negative.
Thus, we can conclude that the statement enthalpy of the reactants is greater than that of the products is true of a reaction with a negative enthalpy.
Answer:
A
Explanation:
trust
Silicon dioxide reacts with carbon to form silicon carbide and carbon monoxide as shown in the unbalanced reaction below. Determine the percent yield of silicon carbide if 79.1 grams of carbon reacts with an excess of silicon dioxide and 67.4 g of silicon carbide is actually recovered.
SiO2 + C → SiC + CO
Some factories that burn coal produce smoke with harmful chemicals,
such as sulfur. Scrubbers are devices that are attached to the
smokestacks to reduce the amount of sulfur put into the atmosphere. To
evaluate the effectiveness of these devices, what data would need to be
collected?
The amount of sulfur emitted by a smokestack before and after the scrubber is attached.
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What is the structure of an amino acid? A. Amino group, phosphate group, pentose sugar, nitrogen base B.Amino group, R group, carboxylic acid group C. Amino group, disulfide group. R group D. Phosphate group, pentose sugar, nitrogen base
Amino acids are the monomers that make up proteins. Each amino acid has the same fundamental structure , which consists of a central carbon atom, also known as the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom.
Amino group, R group, and the carboxylic acid group. Hence, option B is correct.
What are Amino acids?Amino acids are the monomers that makeup proteins.
Each amino acid has the same fundamental structure, which consists of a central carbon atom, also known as the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom.
Hence, option B is correct.
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Discuss the phenomena of sunrise and sunset seen on Earth and describe how they will be different from the perspective of outer space. PLS REPLY ASAP AND EXPLAIN IM DESPEPERATE
Answer:
IM TO LATE SORRY
Explanation:
Write a report on the implications of entropy to a Christian 500 words
calculate the volume of 150 kg of chlorine gas.
as+at+room+temperature+and+pressure
Calculate the volume of 150kg of chlorine gas at room ... Calculate the volume of 150kg of chlorine gas at room temperature and pressure. The volume of one mole of gas at room temperature and pressure is 24.0dm^3. Relative formula mass
Answer:
[tex]{ \tt{at \: \: s.t.p : }} \\ { \bf{0.0355 \: kg \: of \: chlorine \: occupies \: 22.4 \: {dm}^{3} }} \\ { \bf{150 \: kg \: will \: occupy \: ( \frac{150 \times 22.4}{0.0355} )}} \: dm {}^{3} \\ \\ { \tt{ volume = 94647.88 \: {dm}^{3} }}[/tex]
NO2 + H2O =
SO2 + H2O =
H2S + H2O=
SO2+ H2O=H2SO3
H2S+ H2O=H2SO4 +H2
NO2+ H2O= HNO3+NO
Formulating an Investigative Question In this experiment, you will use a track and a toy car to explore the concept of movement. You will measure the time it takes the car to travel certain distances, and then complete some calculations. In the space below, write a scientific question that you will answer by doing this experiment.
Answer:
A scientific question to be asked is; What is the average speed of the toy car?
Explanation:
A scientific question is a question which is well defined, the values in the question can be measured, and the inputs and outputs related to the question are controllable
The parameters measured in the experiment are;
The time elapsed during the movement of the car, Δt
The distance the car moves, d
From the obtained measurements, the value can be calculated is the average speed of the toy car as follows;
[tex]The \ average \ speed \ of \ the \ toy \ car, \ v_{avg} = \dfrac{d}{\Delta t}[/tex]
Therefore, a scientific question to be asked that will be answered by doing the experiment is; What is the average speed of the toy car?
Answer:
Sample Response: How can we change the speed of a toy car on a racetrack to describe the car’s motion?
What did you include in your question? Check all that apply.
a focus on describing the toy car’s motion
a suggestion for a way to change the car’s motion
room for observations and an opportunity to look at motion objective
Explanation:
In the formation of a covalent bond, electrons are …..
A- Gained
B- Transfered
D- Lost
E- Shared
Answer:
E-shared
A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms.
How many mL of 0.013 M potassium hydroxide are required to reach the equivalence point in the titration of 75 mL 0.166 M hydrocyanic acid?
Answer:
957.7mL
Explanation:
Using the formula below;
CaVa = CbVb
Where;
Ca = concentration of acid (M)
Va = volume of acid (mL)
Cb = concentration of base (M)
Vb = volume of base (mL)
According to the information provided in this question:
Ca = 0.166 M
Cb = 0.013 M
Va = 75mL
Vb = ?
Using CaVa = CbVb
0.166 × 75 = 0.013 × Vb
12.45 = 0.013Vb
Vb =12.45/0.013
Vb = 957.7mL
sulfur and oxygen can react to form both sulfur dioxide and sulfur trioxide in sulfur dioxide there are 32.06 grams of sulfur and 32 grams of oxygen in sulfur dioxide there are 32.06 grams of sulfur are combined with 48 grams of oxygen
a. what is the ratio of the weights of oxygen that combine with 32.06 g of sulfur ?
b. How do these data illustrate the law of multiple proportions?
Answer:
Explanation:
In sulfur dioxide there are 32.06 grams of sulfur and 32 grams of oxygen .
In sulfur trioxide there are 32.06 grams of sulfur are combined with 48 grams of oxygen.
The ratio of oxygen which reacts with 32.06 gram of sulfur is 32: 48 .
This ratio is equal to 2 : 3.
This is in accordance with law of multiple proportion because , the ratio of mass of oxygen which reacts with constant mass of sulfur is integral ratio . Hence they are in accordance with law of multiple proportions.
Answer:
sulfur and oxygen can react to form both sulfur dioxide and sulfur trioxide in sulfur dioxide there are 32.06 grams of sulfur and 32 grams of oxygen in sulfur dioxide there are 32.06 grams of sulfur are combined with 48 grams of oxygen
a. what is the ratio of the weights of oxygen that combine with 32.06 g of sulfur?
b. How do these data illustrate the law of multiple proportions?
Explanation:
In sulfur dioxide ([tex]SO_2[/tex])
32.06 g of sulfur reacts with 32.0 g of oxygen.
In sulfur trioxide ([tex](SO_3)[/tex] 32.0 g of sulfur reacts with 48.0 g of oxygen.
So, both th ecom[pounds are made from sulfur and oxygen,
But the amount of oxygen reacts with fixed amount of sulfur that is 32.06 g and it is in proportions that is:
32.0 g : 48.0 g
=2:3.
Hence, the ratio of oxygen combines with sulfur is in the ratio of 2:3.
b.
This data illustrates the law of multiple proportions.
Because the oxygen which is combining with fixed amount of sulfur is in proportions.
Chất được chia làm bao nhiêu loại? Lấy ví dụ cho từng loại.
Which of the following statements about the procedure for distillation is false?
A) You should attach metal clips to the water tubes when you attach them to the condenser.
B) You are to continue heating the round-bottom flask until all liquid has been distilled.
C) When setting up the distillation apparatus, you should use 3 metal clamps.
D) As you conduct the distillation experiment, you are to store your fractions, securely sealed with caps and placed standing upright, in a beaker until you are ready to obtain GC data.
Answer: B) You are to continue heating the round-bottom flask until all liquid has been distilled.
Explanation:
Fractional distillation refers to a method that's useful for the separation of mixtures of solvents whereby there is less than 40°C in the boiling point difference.
With regards to the options given, the incorrect statement about the procedure for distillation is that you are to continue heating the round-bottom flask until all liquid has been distilled. This isn't correct.
Identify which of the following statements about the isotopes of an element is correct.
A. They have the same electron configuration.
B. They have the same mass number.
C. They have the same numbers of protons and neutrons in the nucleus.
D. They have more protons than neutrons.
Answer:
A
Explanation:
because B is wrong as it doesn't have the same mass number. C is wrong as it has different number of neutrons. D is wrong as it has more neutrons than protons.
Which is a thermosetting plastic?
Polythene
PVC
Melamine
Nylon
Are neutralization reactions always exothermic ?
Explanation:
Neutralisation reactions are not always exothermic. ... When an acid is neutralised by an alkali the reaction is exothermic.SInce strong acids and strong bases are completely dissociated in solution, no formal bonds are being broken. The formation of two very strong covalent bonds between hydrogen and the hydroxide ion is responsible for the neutralization reaction's exothermic character.
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stay safe healthy and happy...A hydrocarbon was found to contain 82.8% by mass of carbon. It has
an Mr of 58. Find the empirical and molecular formulas of this
compound.
Answer: C4H10
Explanation: [tex]\left \{ {{12x+y=58} \atop {\frac{12x}{58} =82,8%}} \right. \\[/tex]%
==> x=4, y=10 C4H10
what is the balanced equation of magnesium carbonate decomposes on heating to form magnesium oxide and carbon dioxide
Answer:
ExplaAt high temperatures MgCO3 decomposes to magnesium oxide and carbon dioxide. This process is important in the production of magnesium oxide. This process is called calcining: MgCO3 → MgO + CO2 (ΔH = +118 kJ/mol)
nation:
In the chemical reaction between aqueous magnesium chloride and sodium metal, what chemical amount (mol) of magnesium metal can be precipitated (produced) with 12.6 mol of sodium metal?
Answer:
6.3moles
Explanation:
The balanced equation of the reaction described above between aqueous magnesium chloride and sodium metal is as follows:
MgCl2(aq) + 2Na(s) → 2NaCl(aq) + Mg(s)
From the above equation, 2 moles of sodium metal (Na) produces 1 mole of Magnesium metal (Mg)
Hence, 12.6 mol of Na will produce (12.6/2) mol of Mg.
12.6/2 = 6.3moles of Mg metal.
Give the full fome of PET
Answer:
The full form of PET is Polyethylene Terephthalate.
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Q1: Give the letter of a substance that is a solid at 20 °C
Q2: Give the letter of a substance that is a liquid at 50 °C
Answer:
A1: Z
A2: Y
Explanation:
Q1: Z is the only one with a melting point high than 20 °C.
Q2: Y is the only substance with both a melting point lower than 50 °C and a boiling point higher than 50°C
Name a popular polyester
Answer:
Terylene
Explanation:
Answer: she or his is right the Terylene is a popular polyester which is used in dress materials. PET (Poly Ethylene Terephthalate) is another example of polyester.M
Explanation:
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Chemical bonding may involve any of the following except the
1. change in mass in a chemical reaction
2. unequal sharing of a pair of electrons between two nonmetals
3. electrostatic attraction between two ions
4. transfer of an electron from one atom to another
Answer:
Number 1 is wrong it doesn't change the mass
Chemical bonding may involve any of the following except the " change in mass in a chemical reaction".
What is chemical reaction?A chemical reaction is referred to as a process which it involves the chemical change of one set of chemical compounds into yet another set of chemical substances.
What is chemical bonding?A molecule and compound's atoms, ions, and groups of atoms are held together by an attractive force, referred as chemical bond.
Chemical bonding may involve any of the following except the " change in mass in a chemical reaction".
Therefore, the correct answer will be option 1.
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All samples of a specific substanice have the same chemical
composition
TRUE
FALSE
Answer:
true
Explanation:
What are some properties that can be used to determine a chemical reaction has occurred?
Answer:
Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.
Answer:
Change in Color
Heat is released (bubbles in solution)
Sometimes even a change in texture
A new smell
Formation of a precipitate
Methane is the chief constituent of petroleum fuel
A:yes
B:no
State the method you will use to separate the following substances. (a) calcium carbonate from table salt (b) iodine from sodium chloride (c) table salt from seawater (d) sugar from sugar solution (e) pure water from sewage water (f) ethanol from beer (g) yellow dye from durian ice cream
Answer:
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Answer: There are many forms of table salt: coarse salt, refined salt, iodized salt. It is a crystalline solid, white to very pale pink or gray in color, obtained from seawater or salt deposits. Salt obtained from seawater has crystals that are smaller or larger than rock salt. In nature, table salt consists mainly of sodium chloride (NaCl), but also a few other minerals (trace minerals). Table salt obtained from rock salt may appear more gray because of traces of trace minerals. Table salt is necessary for the survival of all living organisms, including humans. Table salt is involved in regulating the body's water content (liquid balance).
Boyle's Law Problems
Charles' Law Problems
Answer:
here are the answers babe. Feel free to ask for more
How many atoms are in 490 moles of barium?
Answer:
2.95 * 10^23 atoms
Explanation:
The number of atoms in a mole is always equal to Avogadro's constant, which is 6.02214076×10²³ mol⁻¹.
To find the number of atoms in 0.490 moles of barium, multiply it with Avogadro's constant:
0.490 mol * 6.02214076×10²³ mol⁻¹ ≈ 2.9508 * 10^23
Convert to SigFigs (if necessary):
2.95 * 10^23