Answer:
1.physical change because the ice from a solidform cahnged into a liquid form
Câu 15: Nguyên tử X nặng gấp 2 lần nguyên tử cacbon. Nguyên tử X đó có nguyên tử khối và
kí hiệu hóa học là
A. 24_Mg. B. 16_O C. 56_Fe D. 32_S
Answer:
A
Explanation:
A compound's properties are different than the properties of the elements that make it up.
A)True
B)False
The Russian Mir space station used a chemical oxygen generator system to make oxygen for the crew. The system ignited a tube of solid lithium perchlorate (LiClO4) to make oxygen and lithium chloride (LiCl): LiClO4 (s) 2O2 (g) + LiCl (s) If you have 300 g of LiClO4, then… (a) How many moles of oxygen gas will be generated?
(b) The station’s standard operating conditions are a pressure of 101.5 kPa and a temperature of 21°C. Based on this information and your answer to part (a), how many liters of oxygen gas will be generated? (Show your work.)
300 g of LiClO₄ produce 5.64 moles of O₂, which is equivalent to 136 L of O₂ at 101.5 kPa and 21 °C.
Let's consider the following balanced equation.
LiClO₄(s) ⇒ 2 O₂(g) + LiCl(s)
We can calculate the moles of O₂ produced from 300 g of LiClO₄ using the following relationships.
The molar mass of LiClO₄ is 106.39 g/mol.The molar ratio of LiClO₄ to O₂ is 1:2.[tex]300 g LiClO_4 \times \frac{1molLiClO_4}{106.39gLiClO_4} \times \frac{2molO_2}{1molLiClO_4} = 5.64molO_2[/tex]
Then, we will convert 101.5 kPa to atm using the conversion factor 1 atm = 101.325 kPa.
[tex]101.5 kPa \times \frac{1 atm}{101.325kPa} = 1.002atm[/tex]
Next, we will convert 21 °C to Kelvin using the following expression.
[tex]K = \° C + 273.15 = 21\° C + 273.15 = 294 K[/tex]
Finally, we will calculate the volume occupied by 5.64 moles of oxygen using the ideal gas equation.
[tex]P \times V = n \times R \times T\\\\V = \frac{n \times R \times T}{P} = \frac{5.64 mol \times (\frac{0.082atm.L}{mol.K} ) \times 294K}{1.002atm} = 136 L[/tex]
300 g of LiClO₄ produce 5.64 moles of O₂, which is equivalent to 136 L of O₂ at 101.5 kPa and 21 °C.
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A force of 500 N acts over an area of 10 m2. Use the
formula to calculate the pressure.
Answer:
50Pa
Explanation:
pressure= force/area
= 500N/10m2
= 50Pa
According to the law of conservation of matter, which statement about chemical reactions is true? A. Atoms cannot be created or destroyed by chemical reactions. B. Atoms are created by some reactions and destroyed by others. C. Energy is created as atoms are destroyed in chemical reactions. D. Every atom destroyed in a chemical reaction must be replaced.
What is the lead concentration of a saturated solution of lead(II) sulfate containing 0.020 M Na2SO4? Ksp for PbSO4 = 6.3x10-7.
Answer:
i want to help but i d k. the answer :( sorry i couldnt help
Explanation:
The RDI for sodium for adults is 2300mg. What amount of table salt (in grams) contains this quantity of sodium? Express answer to two significant figures and include the appropriate units.
Answer:
hihihihhihihihihiihihihihiihihihih
Calculate the number of Calories in a 5 fluid oz glass of red wine that contains 2.1 g carbohydrate and 13.8 g alcohol.
Answer:
ù
Explanation:
What are the 26 states of matter?
Bose–Einstein condensate.
Fermionic condensate.
Degenerate matter.
Quantum Hall.
Rydberg matter.
Rydberg polaron.
Strange matter.
Superfluid
In this case, the amount of calories is 105 calories.
One gram of alcohol provides approx. 7 calories, whereas one gram of carbohydrates contains 4 calories.In this case, the number of calories can be calculated by summing the calories provided by alcohol and carbohydrates.Number of calories = (2.1g x 4) + (13.8g x 7) = 8.4 + 96.6 = 105 calIn conclusion, the amount of calories, in this case, is 105 calories.
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what happens to a circuits resistance (R), voltage (V), and current (I) when you increase the diameter of the wire in the circuit?
a. R increases, V is constant, I increases
b. R decreases, V is constant, I increases
c. R decreases, V increases, I increases
d. R increases, V decreases, I decreases
Answer:
b. R decreases, V is constant, I increases
Explanation:
when we increase the diameter of wire increases ,resistance decreases and current increases.Therefore, the option is b.
Resistance is an electrical quantity which opposes the electric current in the circuit. Resistance is directly proportional to the length of the wire and inversely proportional to the diameter of the wire. If length of wire increases resistance will increases and if the diameter of the wire increase resistance will decreases.
R = ρ L/A
Here ρ is the resistivity
L is the length of the wire
A is the cross-sectional area of wire/diameter of the wire
Voltage is the potential difference between two terminals of voltage source. Current is the flow of electrons in the circuit. Voltage is the product of current and resistance.
V=IR
Rewrite the above equation interms of current
I=V/R
From the above equation we can say that current is inversly proportional to the resistance.Therefore,the correct option is b.
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A boy rides his bike to his friends house. He travels 2 miles in 8 minutes. What is the boy's average speed? Write the formula, plug in the numbers, and write the answer.
Explanation:
y = 4×
explnation
8÷2 =4
1 mile equals 4 minutes
A boy rides his bike to his friend's house. He travels 2 miles in 8 minutes, the boy's average speed will be 0.25 meters per second (m/s).
What is speed?Speed of any object is the rate of change of position in the given time of interval or given time of the unit is said to be speed an can be measured by dividing the distance traveled with the time.
A boy rides his bike to his friend's house. He travels 2 miles in 8 minutes so the speed will be,
Speed = distance / time
Speed = 2 miles / 8 minutes
Sped = 0.25 meter per second (m/s)
Therefore, the average speed will be 0.25 meters per second (m/s) if the boy rides his bike to his friend's house. He travels 2 miles in 8 minutes.
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Can you help me solve this ?
how are the results of the crosses differ if the red allele was dominant over the white allele? Explain both of the F¹ and F² generations
Answer:
if the red allele is dominant 3 out of 4 offspring will have the red characteristic and 1 out of 4 will have white characteristic
Phản ứng phân hủy dinitơ pentaoxide N2O5 là một phản ứng bậc 1 có giá trị hằng số tốc độ
K = 5,1.10-4
s
-1
tại 45oC.
2N2O5(k) → 4NO2(k) + O2(k)
a. Biết nồng độ ban đầu của N2O5 là 0,25M, hỏi sau 3,2 phút nồng độ của nó là bao nhiêu?
b. Sau bao lâu nồng độ N2O5 giảm từ 0,25M thành 0,15M?
c. Sau bao lâu chuyển hóa hết 62% N2O5?
The change in internal energy for the combustion of cyclohexanol (C6H12O) is -890.7 Kcal per mole. A .708 g sample of cyclohexanol undergoes complete combustion in a bomb calorimeter that has a heat capacity of 2.70 Kcal per degree C. What is the final temperature of the water in the calorimeter if the initial water temperature is 27C?
The final temperature in the calorimeter, with a heat capacity of 2.70 kcal/°C, internal energy for the combustion of cyclohexanol (C₆H₁₂O) of -890.7 kcal/mol and initial temperature of 27°C, is 29.33 °C.
We can find the final temperature of the water in the calorimeter with the following equation:
[tex]\Delta E = -C\Delta T = -C(T_{f} - T_{i})[/tex] (1)
Where:
ΔE: is the change in internal energy for the combustion of C₆H₁₂O = -890.7 Kcal/mol
C: is the heat capacity of the calorimeter = 2.70 Kcal/°C
[tex]T_{f}[/tex]: is the final temperature =?
[tex]T_{i}[/tex]: is the initial temperature = 27 °C
By solving equation (1) for [tex]T_{f}[/tex], we have:
[tex] T_{f} = -\frac{\Delta E}{C} + T_{i} [/tex]
[tex]T_{f} = -\frac{-890.7 \frac{kcal}{mol\: C_{6}H_{12}O}*\frac{1 mol \: C_{6}H_{12}O}{100.158 g \: C_{6}H_{12}O}*0.708 g \: C_{6}H_{12}O}{2.70 kcal/^{\circ}C} + 27 ^{\circ}C = 29.33 ^{\circ}C[/tex]
Therefore, the final temperature of the water is 29.33 °C.
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I hope it helps you!
. The atomic number of a newly discovered element is found to be 128, and its mass number is 279.
How many protons, neutrons, and electrons are found in an ion of this element bearing a charge of
5−?
What is potential energy
Why do you think dark surfaces absorb radiation better than light surfaces?
Your answer→ The lighter side absorbs less of the incident light, reflecting some of the energy. Darker materials also emit radiation more readily than light-colored materials, so they cool faster.
To solve this we must be knowing each and every concept related to radiation. Therefore, dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
What is radiation?According to the energy of the emitted particles, radiation is frequently classified as being either ionizing or non-ionizing. More than 10 eV is often carried by ionizing radiation, which is sufficient to ionize atoms as well as molecules and rupture chemical bonds.
The word refers to radiation having an energy level high enough to ionize atoms, or to remove electrons from atoms to produce ions. Whenever an electron is removed from an atom's electron shell, or, as we may say, when it is "tried to knock out," the action of ionization takes place. Dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
Therefore, dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
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22.2 g of LiCiO4:3H2O in 125 mL of solution
Express your answer in moles per liter to three significant figures.
What is the Molar Mass?
Answer:
Molarity: concentration measured by the number of moles of solute per liter of solution 3)
Explanation:
According to molar concentration, molarity of solution is 1.104 moles per liter and molar mass is 160.437 g/mole.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.
Molarity of solution is obtained as, 22.2/160.437×1/0.125=1.104 moles per liter.Molar mass of LiClO₄.3 H₂O is 160.437 g/mole.
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Which is not a type of nuclear decay?
A. Zeta
B. Gamma
C. Alpha
D. Beta
Answer:
The answer is Zeta
Explanation:
The three types of nuclear decay are Gamma, Beta, and Alpha.
(iii) Explain why magnesium chloride has a high melting point.
Answer:
magnesium chlorides are solids with high melting and boiling points because of the large amount of heat which is needed to break the strong ionic attractions.
Explanation:
These magnesium ions have more than one charge (2+). These highly charged ions will attract other ions more strongly than ions with one charge, therefore more energy will be needed to overcome the electrostatic forces of attraction and so the melting points will be higher.
What is the chemical formula for iron(11) oxide
Answer:
FeO
Explanation:
Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite. One of several iron oxides, it is a black-colored powder that is sometimes confused with rust, the latter of which consists of hydrated iron(III) oxide (ferric oxide).
Which has more calories: table sugar or aspartame?
Answer:
Aspartame produces 4 kilocalories of energy per gram when metabolized, sucrose (table sugar) produces 3.9 kilocalories. However, aspartame is approximately 200 times sweeter than sucrose, so it is consumed in much smaller doses.
Explanation:
Answer is Aspartame.
Think-tank 1. Substances which make up a mixture can be in any combination of the three physical states - solid, liquid or gas. Give an example of a mixture with the following combinations of physical states: a. solid-solid b. liquid-liquid C. gas-gas d. solid-liquid e. solid-gas f. liquid-gas
Answer:
A. orqnges and bananas
B. Water and lemon juice
C. Air ( mixture of oxygen and nitrigen)
D. stones in water
E. smoke ( soot suspended in air)
F. coca cola ( Carbon dioxide dissolved in water)
Alka-Seltzer is pure NaHCO3
True or false?
Answer:
falso
Explanation:
A 3.90 L sealed vessel under vacuum is filled with 6.40 g of fluorine gas. What is the pressure (in kPa) of the vessel at 25.0 ⁰C ?
From the ideal gas law, the pressure of the gas is 106 kPa.
First we must obtain the number of moles of the gas;
Number of moles = mass/molar mass
Molar mass of fluorine gas = 38 g/mol
Number of moles of F2 = 6.40 g/38 g/mol = 0.168 moles
Using the ideal gas equation;
PV = nRT
P = ?
V = 3.90 L
n = 0.168 moles
T = 25.0 ⁰C + 273 = 296 K
R = 8.314 kPa L K-1 mol-1
Substituting values;
P = nRT/V
P = 0.168 moles × 8.314 kPa L K-1 mol-1 × 296 K/3.90 L
P = 106 kPa
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The pressure of the vessel at a temperature of 25 °C is 106.73 KPa
We'll begin by calculating the number of mole of fluorine gas. This can be obtained as follow:
Mass of F₂ = 6.40 g
Molar mass of F₂ = 19 × 2 = 38 g/mol
Mole of F₂ =?Mole = mass / molar mass
Mole of F₂ = 6.40 / 38
Mole of F₂ = 0.168 moleFinally, we shall determine the pressure. This can be obtained as follow:
Volume (V) = 3.90 L
Temperature (T) = 25.0 °C = 25 + 273 = 298 K
Mole of F₂ (n) = 0.168 mole
Gas constant (R) = 8.314 L.KPa/Kmol
Pressure (P) =?PV = nRT
P × 3.9 = 0.168 × 8.314 × 298
P × 3.9 = 416.232096
Divide both side by 3.90
P = 416.232096 / 3.90
P = 106.73 KPaTherefore, the pressure of the vessel is 106.73 KPa
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wat are the dangers of chemicals in the laboratory
Guy’s pleaseeee help
Answer:
A. All isotopes have no charge
in which process water partially breaks down into charged particles?
Answer:
presipitayion
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Describe the difference between at atom and an ion in regards to their substaomic
particles
Answer:
difference between atom and ion
Explanation:
What is an Atom?
The smallest unit of matter. It is indivisible and consists of neutrons, electrons and protons. Atoms can take part in chemical reactions. Combination of atoms together forms molecule. Always the number of protons and electrons are equal. Independent life may or may not be feasible within a solution. Nucleus of the atom is formed by protons and neutrons. Surrounding the nucleus are the electrons.
What is an Ion?
Atoms where the electrons and protons are not equal are called ions. Ions are charged particles. They can be either positively charged ions or negatively charged ions. If an atom is charged electrically it is considered an ion. If an atom contains maximum number of electrons than protons, then it is called anion. If an atom contains maximum number of protons than electrons, then it is called cation. Independent existence in a solution. When an atom gains or loses electrons, ion is formed.
To make you understand how atom and ion are different from each other, here are the some major differences between atom and ion:
WILL MARK BRAINLY
Under what conditions will a low temperature make a reaction spontaneous?
O A. If AH and AS are both positive
O B. If AH and AS are both negative
O c. If a catalyst is used in the reaction
O D. If the reaction is endothermic
Answer:
B
Explanation:
If AH and AS are both negative will a low temperature make a reaction spontaneous.
What is Spontaneous reaction?A spontaneous reaction is a reaction that favors the formation of products at the conditions under which the reaction is occurring. A roaring bonfire (see figure below) is an example of a spontaneous reaction.
A fire is exothermic, which means a decrease in the energy of the system as energy is released to the surroundings as heat.
The products of a fire are composed mostly of gases such as carbon dioxide and water vapor, so the entropy of the system increases during most combustion reactions.
Therefore, If AH and AS are both negative will a low temperature make a reaction spontaneous.
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