Answer:
B changing states of matter (solid to liquid)
PLEASE HELP
How many moles of silane gas (SiH4) are present in 8.68 mL
measured at 18 0C and 1.50 atm?
Answer: There are 0.00054 moles of silane gas (SiH4) are present in 8.68 mL measured at 18 0C and 1.50 atm.
Explanation:
Given: Volume = 8.68 mL (1 mL = 0.001 L) = [tex]8.68 \times 10^{-3} L[/tex],
Temperature = [tex]18^{o}C = (18 + 273) K = 291 K[/tex],
Pressure = 1.50 atm
The ideal gas formula is as follows.
PV = nRT
where,
P = pressure
V = volume
n = no. of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into above formula as follows.
[tex]PV = nRT\\1.50 atm \times 8.68 \times 10^{-3} L = n \times 0.0821 L atm/mol K \times 291 K\\n = \frac{1.50 atm \times 8.68 \times 10^{-3} L}{0.0821 L atm/mol K \times 291 K}\\= \frac{0.01302}{23.8911}\\= 0.00054 mol[/tex]
Thus, we can conclude that there are 0.00054 moles of silane gas (SiH4) are present in 8.68 mL measured at 18 0C and 1.50 atm.
In the 1930s a telephone-company engineer named Karl Jansky was trying to track down
Answer:
In the 1930s a telephone-company engineer named Karl Jansky was trying to track down the cause of hissing static in phone lines when he discovered something strange. Radio energy from outer space was interfering with the phone signals. After learning about Janksy's discovery, a radio engineer named Grote Reber decided to investigate.
Explanation:
How many ATP are directly generated in the Krebs cycle when 2 molecules of glucose are oxidized?
4 ATP molecules are directly generated in the Krebs cycle when 2 molecules of glucose are oxidized
How Krebs cycle move to produce glucose molecule?The Krebs cycle, TCA cycle or the citric acid cycle, is a series of enzyme-catalyzed reactions occurring in the mitochondrial matrix and involves the oxidation of acetyl-CoA.
The acetyl group of acetyl-CoA is oxidized to make two molecules of CO2 in a succession of eight steps, while also producing one ATP. Additionally, reduced high-energy molecules like NADH and FADH2 are created.
Each glucose molecule produces two acetyl-CoA molecules, the Krebs cycle must move twice for one glucose molecule to produce the four CO2, six NADH, two FADH2, and two ATPs.
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A gas made up of atoms escapes through a pinhole 0.920 times as fast as Cl 2 gas. Write the chemical formula of the gas
Answer:
The gas with molar mass 83.9 g is Krypton, Kr
Explanation:
We know that as per Ghram's law of diffusion,
r'/ r= square root (M/M')
0r [tex]\frac{r'}{r } =\sqrt{\frac{M}{M'} }[/tex]
Where
r= rate of diffusion of Cl2
r'= rate of diffusion of unknown gas= 0.920r
Also, M= molar mass of Cl2= 71 g/ mol
And, M'= molar mass of unknown gas which we have to find
Let us substitute the values in above equation
[tex]\frac{0.920r}{r } =\sqrt{\frac{71}{M'} }[/tex]
solving we get M' = 83.9 g/mol
Therefore, the gas with molar mass 83.9 g is Krypton,Kr
In general, which of the following ranks the repulsions indicated from weakest to strongest? O Lone pair-bonding pair, lone pair-lone pair, bonding pair---bonding pair O Bonding pair-bonding pair, lone pair-bonding pair, lone pair-one pair O Lone pair-lone pair, lone pair-bonding pair, bonding pair-bonding pair O Lone pair-bonding pair, bonding pair-bonding pair, lone pair-one pair
Option B, Bonding pair-bonding pair, lone pair-bonding pair, lone pair-lone pair. The electrons in bonding pairs are repulsion held relatively closely together, and are involved in the formation of a chemical bond.
The repulsion between two bonding pairs is relatively weak, as they are attracted to the positively charged nuclei of the atoms they are bonding. The repulsion between a lone pair of electrons and a bonding pair of electrons is generally stronger than that between two bonding pairs because the lone pair is not involved in bonding and tends to be held further away from the nucleus, causing the electron cloud to be larger and thus a stronger repulsion because the two lone pairs are not involved in bonding, and are held relatively far away from the nuclei, causing the electron clouds to be larger and thus a stronger repulsion
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What causes stress in rocks? and What happens when stress is released?
If an engineer is designing a building in an area that has an occasional
supersonic flight pass over it, the engineer should:
A. Design the building with extra stores of oxygen for the workers in
case of emergencies caused by sonic booms.
B. Build the structure using materials that are heat resistant because
of the sonic booms.
C. Design extra reinforcements in the building's windows so that they
can withstand the vibrations from sonic booms.
D. Design the building with solar panels that can provide energy in
case of electrical outages due to sonic booms.
Design extra reinforcements in the building's windows so that they can withstand the vibrations from sonic booms.
What are Sonic booms?
Sonic booms are shock waves created when an object, such as an aircraft or spacecraft, travels through the air at a speed faster than the speed of sound (approximately 767 mph). Sonic booms generate a loud noise that can be heard over long distances. Sonic booms can cause property damage and are hazardous to people's hearing.
Extra reinforcements in the building's windows can help to absorb the shock of sonic booms. This is done by adding additional layers of materials such as glass, plastic, rubber, or metal to the window frame. These materials will help to dampen the vibrations from sonic booms, reducing the noise and preventing damage to the windows. Additionally, window seals can be installed to reduce air infiltration, further helping to protect the windows from the vibrations of sonic booms.
Hence, Option C is correct.
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Jordan places a hot spoon into a container of ice cream. How does this help him scoop out the ice cream?
1 The coolness from the ice cream is conducted to the spoon making it easier to scoop out.
2 The warmth of the spoon is conducted to the ice cream making it easier to scoop out.
3 The coolness from the ice cream is radiated to the spoon making it easier to scoop out.
4 The warmth of the spoon is radiated to the ice cream making it easier to scoop out.
Answer:
Option 2:
The warmth of the spoon is conducted to the ice cream making it easier to scoop out.
Explanation:
Conduction refers to the transfer of heat from a hotter body to a cooler one, by virtue of physical contact between the two bodies. This is opposed to radiation, where there does not need to be any contact between the two bodies before heat con flow.
The warm spoon, once it has physical contact with the cool ice cream, it loses some of its heat to the ice cream, warming it up, making it easier to scoop up.
Students are challenged to design cold packs for treating injuries. To do this they must find a chemical reaction that absorbs heat energy. The ideal chemical reaction will reach a temperature in the range of 0C to 4C and maintain that temperature for a minimum of 20 minutes
Students as a chemical reaction that absorbs thermal energy for the design of cold packs for the treatment of injuries can combine manganese oxide (MnO2) with hydrogen peroxide (H2O2)
By controlling the amounts of the reactants they can control the temperature, keeping it between 0 °C and 4 °C for 20 minutes or more.
This type of chemical reaction is called endothermic, because energy is absorbed in the form of light or heat, causing the resulting products to have higher energy than the reactants.
Chemical reaction that absorbs thermal energy fpr cold compresses for the treatment of injuriesThe most widely used endothermic chemical reaction in the treatment of injuries is the melting of ice, at least in warm environments, which occurs according to the following reaction:
H2O (s) + Energy ----- H2O (l)
Decomposition of manganese oxide absorbs thermal energyThe effect of an endothermic reaction is absorbs heat energy and in the case of manganese oxide the following decomposition occurs:
MnO2 (s) → MnO (s) + ½ O2 (g); ∆HR = 134kJ
Students can design cold packs for treating injuries with manganese dioxide bcause it breaks down into two products, manganese oxide and oxygen, making the enthalpy greater than zero (∆HR > 0).
MnO2 is a solid between gray and black in color and is present in minerals such as pyrolusite and nsutite, when combined with hydrogen peroxide it acts as a catalyst so that it accelerates chemical reaction
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what percent composition tell you about a molecule
Answer:
tells you by mass what percent of each element is present in a compound.
Explanation:
Suppose that 13g of a nonelectrolyte is dissolved in 0.50 kg of benzene. The
boiling point of this solution is 80.61 °C. The normal boiling point of benzene is
80.10 °C. The molal boiling point elevation constant for benzene is 2.53 °C/m. What is the
molar mass of the solute?
Answer:
128.98 g/Mol
Explanation:
ΔTb = Kb * m * i
Where;
ΔTb = boiling point elevation
Kb = boiling point constant
m = molality of the solution
i = Van't Hoff factor
Hence;
Where molality = number of moles of solute/mass of solvent in Kg
Number of moles of solute = mass/Molar mass
So;
80.61 - 80.10 = 2.53 * 13g/M/0.5 * 1
Where M is the molar mass of the solute
0.51 = 2.53 * 13g/M/0.5
0.51 = 2.53 * 13/M * 1/0.5
0.51 = 32.89/M * 1/0.5
0.51 * 0.5 = 32.89/M
0.255 M = 32.89
M = 32.89/0.255
M= 128.98 g/Mol
What do these two changes have in common?
an engine using gasoline to power a car
cellular respiration
Select all that apply.
Both are only physical changes
Both converse mass
Both are chemical changes
Both are caused by heating
Answer: Both are only physical changes
Both converse mass
Explanation: the first two ones r correct
can u help me please
Answer:
weak
Explanation:
this is my best guess
How many energy levels/electron shells does beryllium have?
Maybe for sure its element number as five and two in for as Number of electrons in each level?
How many moles of neon are in 7.6 x 10^23 in sig figs
Answer:
1.26 moles
Explanation:
Applying Avogadro's constant.
1 mole of every substance, has a particle of 6.02×10²³
From the question,
If,
1 mole of Neon contains 6.02×10²³ particles
Therefore,
x moles of Neon will contain 7.6×10²³ particles
x = (7.6×10²³)/(6.02×10²³)
x = 1.26 moles.
Hence the number of moles of Neon present is 1.26 moles
Prior to making your first extrication cut, you must first stabilize the vehicle. What tool will you use
Cribbing is the tool we use prior to making your first extrication cut in the vehicle
Before making the first extrication cut, it is important to stabilize the vehicle to prevent it from moving and to ensure the safety of the individuals involved in the extrication process. One tool that is commonly used to stabilize a vehicle during extrication is a set of stabilizing struts, also known as cribbing. Cribbing is a set of wooden or composite blocks that are placed under the vehicle to support it and prevent it from moving. The cribbing is typically placed at strategic points, such as the frame of the vehicle or the wheels, to provide a stable base for the vehicle.Additionally, other tools like wheel chocks, jacks, and air bags may be used to provide additional support and stability. The extrication team will assess the situation and choose the most appropriate tool to stabilize the vehicle.
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write two ionic equation to show that aluminium hydroxide is amphoteric
Answer:
Explanation:
Aluminium hydroxide is amphoteric. 3 HCl + Al(OH)3 → AlCl3 + 3 H2O. In bases, it acts a Lewis acid by taking an electron pair from the hydroxide ions: Al(OH)3 + OH− → Al(OH)
When 45. 8 g of alanine (C3H7NO2) are dissolved in 1200g of a certain mystery liquid X, the freezing point of the solution is 4. 10 ℃ less than the freezing point of pure X. Calculate the mass of sodium chloride that must be dissolved in the same mass of X to produce the same depression in freezing point. The van't Hoff factor i=1. 82 for sodium chloride in X. Be sure your answer has a unit symbol, if necessary, and is rounded to the correct number of significant digits
16.5 g is the mass of sodium chloride that must be dissolved in the same mass of X to produce the same depression at freezing point.
What are a molar mass and a mole?Avogadro's number (6.022 x 1023) of molecules (or formula units) make up one mole of a substance (ionic compound). The mass of 1 mole of a chemical is indicated by its molar mass. It provides you with the number of grams per mole of a substance, to put it another way.
ΔT = Kc*W*i
Kc = cryoscopy constant of the solute X
W = molality of the solution
i = van't Hoff factor, For organic molecules, such as alanine, i = 1.
n = 45.8/89.09
n = 0.5141 mol
W = 0.5141/1.2 = 0.4284 mol/kg
So, Kc of X is:
4.10 = Kc*0.4284*1
Kc = 9.57 °C.kg/mol
So, if now sodium chloride is added to X, and the temperature change is the same, and i = 1.82:
4.10 = 9.57*W*1.82
W = 0.2354 mol/kg
The number of moles of the solute is then:
W = n/1.2
0.2354 = n/1.2
n = 0.2825 mol
The molar mass of sodium chloride is 58.44 g/mol, thus the mass is the molar mass multiplied by the number of moles:
m = 58.44*0.2825
m = 16.5 g
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According to the data, the temperature of the
substance is 28°C. If we know that 0°C = 273 K,
what is the temperature of the substance in
Kelvin?
Answer: 351
Explanation: From °C to kelvin we do
K=273+°C
From Kelvin to °C we do
°C=K-273 or -273+ K
How does atomic number affect properties?
The atomic number is the number of protons in the nucleus of an atom and it directly affects the properties of an element. The atomic number also determines the element's place in the periodic table, which allows us to predict the properties of an element based on its atomic number.
As the atomic number increases, the number of protons in the nucleus increases and so does the atomic number. This increase in protons also increases the number of electrons in the atom. The number and arrangement of electrons in an atom directly affect its chemical behavior and thus the properties of the element.
The atomic number also determines the element's position on the periodic table, and elements with similar atomic numbers have similar chemical and physical properties. For example, elements in the same vertical row (group) have similar chemical properties, and elements in the same horizontal row (period) have similar electronic configurations of their atoms.
The atomic number also affects the reactivity of an element. Elements with lower atomic numbers tend to be more reactive than elements with higher atomic numbers.
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C. If 71.2 grams of Beryllium Chloride is reacted with 161 grams of
Potassium Nitrate, identify the limiting and excess reactants.
Answer: rytesttrt5rtr
Explanation:
Glass is typically produced by mixing sand (quartz or silica, SiO_2) with other compounds or minerals, which are then crushed, melted, and then cooled (vitrification). Given the compositions and properties of the different types of glass in the table above, consider the role each compound plays in the type of glass formed, and then complete the statements below. Match the compounds in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Adding to the mixture that undergoes vitrification produces a glass with brilliant optical properties. Adding to the mixture that undergoes vitrification produces a glass that can be used for baking purposes or storing chemical solutions. Adding to the mixture that undergoes vitrification produces a glass that is insoluble in water. Adding to the mixture that undergoes vitrification allows the glass to be produced at much lower temperatures.
Addition of soda (Na₂CO₃) to the vitrifying mixture produces glasses with excellent optical properties.
Give a brief account on silica?Silica is the common name for the compound silicon dioxide, which consists of one silicon atom and two oxygen atoms. It is an important component of many rocks, sands, and clays, and is also found in many plants and animals. Silica is used in a wide variety of products, from beer and wine to pottery, glass, and paint. It is also used in building materials such as concrete and mortar, and as a food additive. Silica is also used to make silicon-based electronics such as computer chips.
Adding lime (CaCO₃) to the vitrifying mixture creates a jar that can be used to bake or store the liquid medicine.
Addition of alumina (Al₂O₃) to a mixture undergoing vitrification produces a glass that is insoluble in water.
Addition of borax (Na₂B₄O₇) to the mixture during vitrification allows glass to be produced at much lower temperatures.
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The faster the object is moving the more portential energy it has?
Answer:
sure
Explanation:
What observation is made when magnesium powder and lead(ii) are heated together
Answer:
in the lead strip the will be no change and no reaction. this is job salvation that is made when magnesium powder and lead to our heater together
Magnesium reacts with lead(II) nitrate. Type of reaction ____________________________ Balanced chemical equation:
The type of reaction is a double replacement reaction. In a double replacement reaction, the positive ions of two compounds switch places to form two new compounds.
What is the balanced chemical equation for the reaction?The balanced chemical equation for the reaction between magnesium and lead(II) nitrate is:
Mg(s) + Pb(NO3)2(aq) -> Mg(NO3)2(aq) + Pb(s)
In this equation, the magnesium and lead ions switch places to form the new compounds magnesium nitrate and lead. The coefficients in front of the compounds indicate the number of moles of that substance that are involved in the reaction. The subscripts indicate the number of atoms of each element in each compound.
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Fe(OH)3
⎯⎯→
Fe2O3
⎯⎯→
Fe
⎯⎯→
FeCl2
⎯⎯→
Fe(OH)2
Answer:
decomposition reaction
Hi what's the answer to this
Explanation:
Atoms are tiny spheres that cannot be divided
Calculate the mass, in grams, of 0.965 mol of sodium hydroxide
(NaOH), in a drain cleaning solution.
Answer:
38.51g NaOH
Explanation:
NaOH=39.907 g/mol
0.965 mol NaOH X 39.90g NaoH/1 mol NaOH= 38.51 g NaOH
Complete this Lewis structure for S2O32− by adding lone pairs and formal charges.
Add lone-pair electrons and formal charges to this structure.
The complete lewis structure is shown in the below figure by adding lone pairs and formal charges.
Assign the valence electrons to each atom as dictated by the periodic table placing one electron at each compass direction and then pairing them only after the first four until you have place all of the atom’s valence electrons. (See the Roman numeral above the group/column it is in.)
Arrange the remaining atoms around the central atom and join them to the central atom by a single bond. The more electronegative atoms are typically farther away from the center and attaching hydrogen last is advised.
Lone electrons (not lone pairs) indicate an ability to form more covalent bonds, resulting in either double or triple bonds. Their presence or the lack of a full octet on any atom indicates there is a better Lewis structure.
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Which salt is formed by the reaction between hydrochloric acid and sodium hydroxide, write with chemical equation. .
Answer:
salt sodium chloride (NaCl)