Answer:
most flowering plants are classified as angiosperms
Answer:
I think the answer is Bryophyta
Explanation:
seedless,non vascular plants that are the closest extant relative of early terrestrial plants
the total energy gain of the ice cube and the resulting liquid water is blank joules
Answer:
bro
Explanation:
bro
Answer: yes
Explanation:
Because of the mass
Find the area of the sector with a central angel of 120 and a radius of 8 inshces. Leave in terms of pie
Answer:
A = 66.98 square in.
Explanation:
The Area of a sector is given by the formula
[tex]A = \frac{\theta}{360}\times \pi r^2[/tex]
here θ is the central angle and r is the radius
given that θ = 120° and radius = 8 inches
[tex]A = \frac{120}{360}\times3.14\times 8^2[/tex]
A = 66.98 square in.
What is the mass of 10.5 moles of H20?
Answer:
180g
Explanation:
So, 10 mole of water will weigh (18x10) = 180g.
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what happened to the ionization energy of hydrogen"H" when its electron affinity
Método científico: El trabajo científico se caracteriza por ser planificado, con objetivos iniciales y que habitualmente se dan en un cierto orden.1) Indica cuáles son los pasos del método científico explicando brevemente cada uno de ellos.2) Los siguientes son dos modelos : *Un estudiante pensando en la competencia, desarrolla un proyecto en el sótano de su casa. *Un grupo de personas con diferentes aptitudes cooperan para resolver un problema. ¿Cuál de ellos es mejor para el trabajo científico? ¿Por qué?
Answer:
Ver explicación
Explanation:
El método científico se refiere al patrón establecido de resolución de un problema científico. Los siguientes son pasos importantes en el método científico;
Haz una observación.
formular preguntas relevantes.
elabore una hipótesis que pueda ser probada.
Diseña un experimento.
Prueba la hipótesis usando tu diseño experimental.
Teniendo en cuenta ambos escenarios, el último caso en el que estudiantes de diferentes capacidades trabajan juntos para resolver un problema refleja mejor el método científico porque pueden hacerse preguntas entre sí y llegar a hipótesis comprobables que pueden demostrarse como verdaderas o falsas mediante experimentos.
3 upper M n upper O subscript 2 (s) plus 4 upper A l (s) right arrow 2 upper A l subscript 2 upper O subscript 3 (g) plus 3 upper M n (s). What is the enthalpy of the reaction?
Answer: The enthalpy of the reaction is -1791.31 kJ.
Explanation:
Enthalpy change is the difference between the enthalpies of products and the enthalpies of reactants each multiplied by its stoichiometric coefficients. It is represented by the symbol [tex]Delta H^o_{rxn}[/tex]
[tex]\Delta H^o_{rxn}=\sum (n \times \Delta H^o_{products})-\sum (n \times \Delta H^o_{reactants})[/tex] .....(1)
For the given chemical reaction:
[tex]3MnO_2(s)+4Al(s)\rightarrow 2Al_2O_3(s)+3Mn(s)[/tex]
The expression for the enthalpy change of the reaction will be:
[tex]\Delta H^o_{rxn}=[(2 \times \Delta H^o_f_{(Al_2O_3(s))}) + (3 \times \Delta H^o_f_{(Mn(s))})] - [(3 \times \Delta H^o_f_{(MnO_2(s))}) + (4 \times \Delta H^o_f_{(Al(s))})][/tex]
Taking the standard heat of formation values:
[tex]\Delta H^o_f_{(Al_2O_3(s))}=-1675.7kJ/mol\\\Delta H^o_f_{(Al(s))}=0kJ/mol\\\Delta H^o_f_{(MnO_2(s))}=-520.03kJ/mol\\\Delta H^o_f_{(Mn(s))}=0kJ/mol[/tex]
Plugging values in the above expression:
[tex]\Delta H^o_{rxn}=[(2 \times (-1675.7))+(3 \times 0)] - [(3 \times (-520.03))+(4 \times 0)]\\\\\Delta H^o_{rxn}=-1791.31 kJ[/tex]
Hence, the enthalpy of the reaction is -1791.31 kJ.
Give the systematic name for PbO2
The systematic name for PbO₂ is lead dioxide.Therefore, the correct option is A.
What are systematic names?Systematic names are a type of chemical nomenclature that follow a systematic set of rules to name chemical compounds. Lead dioxide (PbO₂) is a chemical compound composed of lead and oxygen. It is an oxide of lead and can also be called lead(IV) oxide.
The systematic name of the compound is derived by using the root word of the metal, “lead,” and adding the suffix “-dioxide” to indicate the two oxygen atoms. Thus, the systematic name for PbO₂ is lead-dioxide.Therefore, the correct option is A.
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The question is incomplete, but most probably the complete question is,
Give the systematic name for PbO₂?
A. Lead dioxide
B. Lead trioxide
C. Lead oxide
D. Lead azide
HELP PLEASEEEEE HURRY!!
Answer:
The answer is c
write an equation for the reaction in which hydrochloric acid neutralises sodium hydroxide
Answer:
ok
Explanation:
A salt is a neutral ionic compound. Let's see how a neutralization reaction produces both water and a salt, using as an example the reaction between solutions of hydrochloric acid and sodium hydroxide. The overall equation for this reaction is: NaOH + HCl -> H2O and NaCl.
in need of correct answer por favor
Answer:
B
Explanation:
because HCl donates a proton to water. Therefore, HCl is an acid. H2O accepts a proton from HCl. Therefore, H2O is a base.
Write the electron configuration for Gold (Au). You may choose to write it in the long form or in the noble gas configuration form (shortcut).
Answer:
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s¹4f¹⁴5d¹⁰
Explanation:
How long is radioactive waste from nuclear plants radioactive?
1.) 100,000 years
2.) 10,000 years
3.) 100 years
4.) 1,000 years
A student needs to make a solution of 308 mL of 0.02 M of Copper (II) Sulfate. All they have available is a solution of 0.250 M. How many liters should they use?
Answer:
this link not hacl belive me
https://www.flinnsci.com/api/library/Download/18ce587821c24fb3b0ad7d878bd6a3d9Explanation:
Match the parts of the nervous system with their functions.
cerebrum
brain stem
cerebellum
meninges
regulating breathing
memorizing a telephone number
dancing
protecting the central nervous system
Take two samples, one is oil and other is water. Mix the two. You observe that?
Answer:
Explanation:mckxmmxkmsskkskskskxisisisisisisisks
a buffer solution is prepared by adding NH4Cl to a solution of NH3 (ammonia). what happens if NaOH is added?
NH3(aq)+ H2O(l) = NH4+(aq) +OH- (aq)
Answer: The reaction proceeds in the backward direction.
Explanation:
A buffer is a solution that maintains the pH of the solution and resists any significant changes of pH on the addition of acid or alkali.
A buffer solution of [tex]NH_4Cl\text{ and }NH_3[/tex] is prepared. It is a basic buffer as it is formed by the combination of a weak base [tex](NH_3)[/tex] and its conjugate acid [tex](NH_4Cl)[/tex]
When a strong base (NaOH) is added to this buffer solution, the ammonium ions releases hydrogen ion to the solution which then combines with the hydroxide ions to form water and ammonia in a solution. Thus, maintaining the pH of the buffer.
The given chemical equation follows:
[tex]NH_3(aq)+H_2O(l)\rightleftharpoons NH_4^+(aq)+OH^-(aq)[/tex]
Hence, the reaction will proceed in the backward direction.
When NaOH is added to this buffer solution it forms water and ammonia.
A buffer is a solution that maintains the pH of the solution and maintains the pH on the addition of acid or alkali.
A buffer solution of [tex]NH_4Cl[/tex] and [tex]NH_3[/tex] is is a basic buffer as it is formed by the combination of a weak base and its conjugate acid.
When a NaOH which is a strong base is added to this buffer solution, the ammonium ions release hydrogen ion which combines with the hydroxide ions to form water and ammonia helps maintain the pH of the buffer.
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What is the general form of a synthesis reaction?
O A. AB + CD → AC + BD
B. A + B → AB
O C. AB + C → AC + B
D. AB → A+B
Be
The answer is B
Answer:
B. A+ B → AB
Explanation:
general form of a synthesis reaction
Un gas ocupa un volumen de 358L a 152°C y 470 mmHg ¿Qué volumen ocupara el gas, si la temperatura aumente a 500 K y 6 atm?
Answer:
42 L
Explanation:
de los parámetros en la pregunta;
V1 = 358L
T1 = 152 ° C + 273 = 425 K
P1 = 470 mmHg × 1 atm / 760 mmHg = 0.6atm
V2 =?
P2 = 6 atmósferas
T2 = 500 K
P1V1 / T1 = P2V2 / T2
P1V1T2 = P2V2T1
V2 = P1V1T2 / P2T1
V2 = 0,6 × 358 × 500/6 × 425
V2 = 107400/2550
V2 = 42 L
Enough nitrogen must be generated in the bag to create a total pressure of 2.56 atm, which then drops as the bag slowly deflates. Assuming the volume of the bag is 56.0 L and the temperature in the car is 25oC, calculate the molar quantity (number of moles) of N2 that must be generated.
Hint: Use Ideal gas law PV=nRT (Ideal gas constant R=0.080 L.atm/mol.K)
Answer:
The number of moles is 6.01 moles.
Explanation:
An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:
P*V = n*R*T
where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas. The universal constant of ideal gases R has the same value for all gaseous substances.
In this case:
P= 2.56 atmV= 56 Ln= ?R= 0.080 [tex]\frac{atm*L}{mol*K}[/tex]T= 25 C= 298 K (being 0 C= 273 K)Replacing:
2.56 atm* 56 L= n* 0.080 [tex]\frac{atm*L}{mol*K}[/tex]* 298 K
Solving:
[tex]n=\frac{2.56 atm*56 L}{0.080\frac{atm*L}{mol*K}*298 K}[/tex]
n= 6.01 mol
The number of moles is 6.01 moles.
Which of these takes place when a chemical change occurs? option 1: Bonds connecting atoms in products and reactants form. option 2: Bonds connecting atoms in products and reactants break. option 3: Bonds connecting atoms in reactants break, and bonds connecting atoms in products form. option 4: Bonds connecting atoms in reactants form, and bonds connecting atoms in products break.
Answer: Out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.
Explanation:
A change that leads to the change in chemical composition of a substance is called a chemical change.
For example, [tex]2NH_{3} \rightarrow N_{2} + 3H_{2}[/tex]
Here, bond between the reactant atoms nitrogen and hydrogen is broken down.
On the other hand, bond connecting the products that is [tex]N_{2}[/tex] and [tex]H_{2}[/tex] is formed.
Thus,, we can conclude that out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.
I might honestly fail miserably on my chemistry final tomorrow. Would anyone be able to give some last-minute advice?
You are a NASCAR pit crew member. Your employer is leading the race with 20 laps to go. He just finished a pit stop and has 5.0 gallons of fuel in the tank. On the way out of the pits, he asks, "Am I going to have enough fuel to finish the race or am I going to have to make another pit stop?" You whip out your calculator and begin your calculations based on your knowledge of stoichiometry. Other information you know is: The car uses an average of 300.0 grams of O2 for each lap. The formula for fuel is C5H12. The fuel has a density of 700 g/gal. What do you tell the driver? (The density can be used as a conversion factor between grams and gallons)
Answer:
Since there are 3500 g of fuel left in the tank, and he needs only 1687.5 g to complete 20 laps, he has enough fuel to complete the race. I will tell the driver that he does not need to make another pit stop as he has enough fuel to complete the race.
Explanation:
Density = mass / volume
Density of fuel = 700 g/ 1 gal
Therefore, the mass of fuel in 1 gallon = 700 g
The driver has 5.0 gallons of fuel in the tank.
The mass of 5.0 gallons of fuel = 5 × 700 = 3500 g of fuel
Equation of the combustion of fuel, C₅H₁₂ is given below:
C₅H₁₂ + 8 O₂ ---> 6 H₂O + 5 CO₂
1 mole C₅H₁₂ requires 8 moles of O₂
1 mole of C₅H₁₂ has a mass = 72 g
8 moles of O₂ has a mass = 256 g
Therefore, 300 g of O₂ will require 300 × (72/256) g of C₅H₁₂ = 84.375 g of C₅H₁₂
84.375 g of fuel is used by the car per lap;
20 laps will require 20 × 84.375 g of fuel = 1687.5 g of fuel.
Since there are 3500 g of fuel left in the tank, and he needs only 1687.5 g to complete 20 laps, he has enough fuel to complete the race. I will tell the driver that he does not need to make another pit stop as he has enough fuel to complete the race.
Which statement accurately describes a P wave?
Answer:
A P wave can move through solid rock only. P wave can travel through liquid accurately describes a P wave.
Determine the volume of a helium balloon given the balloon was filled from a container 0.15L of gas at 2 atm if the new pressure is 0.97 atm. Assume constant temperature.
Answer:
The volume of the helium balloon is 0.306 L.
Explanation:
Boyle's law states that the volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure. That is, if the pressure increases, the volume decreases, while if the pressure decreases, the volume increases.
Mathematically, Boyle's law indicates that the product of pressure and volume always has the same value:
P*V= k
Assuming that you have a certain volume of gas V1 that is at a pressure P1 at the beginning, by varying the volume of gas to a new value V2, then the pressure will change to P2, and it will be fulfilled:
P1*V1= P2*V2
In this case:
P1= 2 atmV1= 0.15 LP2= 0.97 atmV2= ?Replacing:
2 atm* 0.15 L= 0.97 atm* V2
Solving:
[tex]V2= \frac{2 atm* 0.15 L}{0.97 atm}[/tex]
V2= 0.306 L
The volume of the helium balloon is 0.306 L.
The
volume
occupied by 5.0g in neon
03368 atm and
a temperatureof
35°C will be?
Answer:
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HELP ;-;
Vanillin, C8H8O3, the principal component of vanilla beans, is very similar to glucose, C6H12O6 a type of sugar. Brittany Spears has a life threatening allergy to vanillin. After one of her concerts she was found dead in her dressing room. A glass lined with a white powder was found smashed on the floor next to her. Police think the glass was lined with vanillin suggesting she was murdered. A 2.54 g sample of this powder underwent carbon-hydrogen analysis. It’s combustion was found to produce 5.875 g of CO2 (g) and 2.41 g of H2O(g) . Find the empirical formula of this compound and determine if Brittany may have been poisoned?
b) Is this evidence enough to conclude for certain that the identity of the powder on the glass is indeed vanillin? Why or why not?
Answer:
The empirical formula is: CH2
Th powder is not vainillin
Explanation:
We can find empirical formula of a compound CₐHₓOₙ knowing that moles CO2 = Moles C, 2 Moles H2O = Moles H and that we can find the mass of oxygen by the difference of masses of the atoms:
Moles C = Moles CO2 -Molar mass: 44.01g/mol-
5.875g * (1mol/44.01g) = 0.1335 moles C * (12.01g/mol) = 1.60gC
Moles H2O and moles H -Molar mass: 18.01g/mol-
2.41g H2O * (1mol / 18.01g) = 0.1339 moles H2O * (2mol H / 1mol H2O) =
0.2676 moles H * (1g/mol) = 0.27g H
The empirical formula of this compound is the ratio of C:H:
0.2676 moles H / 0.1335 moles C = 2
The empirical formula is:
CH2
In vainillin, the moles of Carbon = Moles of Hydrogen. the experiment shows the moles of hydrogen are twice the moles of carbon. Thus, the powder is not vainillin
What happens to the freezing point of a solution when more solute is added?
Answer:
Explanation:
Freezing point depression is the phenomena that describes why adding a solute to a solvent results in the lowering of the freezing point of the solvent. Adding solute to a solvent will essentially dilute the solvent molecules
Answer:
The freezing point decreases
In the reaction shown below, ____________ acts as a base because ___________. HCO3- + H2O à H3O+ + CO32-
Answer: In the reaction [tex]HCO^{-}_{3} + H_{2}O \rightarrow H_{3}O^{+} + CO^{2-}_{3}[/tex], [tex]H_{2}O[/tex] acts as a base because it has accepted a hydrogen ion or proton.
Explanation:
According to Arrhenius, species which dissociate to give hydrogen ions when dissolved in a solvent like water are called acid.
A species which readily accepts a hydrogen ion or proton is called a base.
For example, [tex]HCO^{-}_{3} + H_{2}O \rightarrow H_{3}O^{+} + CO^{2-}_{3}[/tex]
Here, [tex]HCO^{-}_{3}[/tex] is donating hydrogen ion. So, it is an acid whereas [tex]H_{2}O[/tex] is accepting the hydrogen ion. Hence, [tex]H_{2}O[/tex] is a base.
Thus, we can conclude that in the reaction [tex]HCO^{-}_{3} + H_{2}O \rightarrow H_{3}O^{+} + CO^{2-}_{3}[/tex], [tex]H_{2}O[/tex] acts as a base because it has accepted a hydrogen ion or proton.
The reaction of hydrogen with nitrogen to produce ammonia is shown below. If there are 3 moles of nitrogen, how many moles of hydrogen are needed to react completely with the nitrogen?
Answer:
9
Explanation:
I took the same test :)
The stoichiometry is important in chemistry which helps us to use the balanced equation to calculate the amount of reactants and products. Here the moles of hydrogen needed is 9. The correct option is B.
What is stoichiometry?The quantitative study of the reactants and products involved in a chemical reaction is known as the chemical stoichiometry. The stoichiometric coefficients can be fractions including the whole numbers. It helps to establish the mole ratio.
The stoichiometric coefficient is basically the number which is present in front of the atoms, molecules or ions. The stoichiometric calculations are also used in gravimetry and volumetry.
Here the balanced equation for the reaction is:
N₂ + 3H₂ → 2NH₃
Number of moles of H₂ = 3 mol N₂× 3 mol H₂ / 1 mol N₂ = 9 mol H₂
So the number of moles of H₂ is 9.
Thus the correct option is B.
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