Câu 36: _VD _Hình lập phương có thể tích là 1253 thì diện tích đáy là:
A. cm2 B. 5cm2 C. 25cm2 D. 52cm2
Answer:
c
Explanation:
Cạnh của hình lập phương là
³\(125 = 5cm
Diện tích đáy của hình lập phương là
5²=25cm²
Đáp án C
What mass of helium gas (in g) occupies 15.3 L at STP?
Answer:
[tex]\boxed {\boxed {\sf 2.73 \ g \ He}}[/tex]
Explanation:
We are asked to find the mass of helium gas given a volume.
1. Convert Liters to Moles1 mole of any gas occupies a volume of 22.4 liters. So, 1 mole of helium gas contains 22.4 liters of helium. Create a ratio using this information.
[tex]\frac {1 \ mol \ He }{ 22.4 \ L \ He}[/tex]
We are converting 15.3 liters of gas to moles, so we multiply by that value.
[tex]15.3 \ L \ He *\frac {1 \ mol \ He }{ 22.4 \ L \ He}[/tex]
The units of liters of helium (L He) cancel.
[tex]15.3 *\frac {1 \ mol \ He }{ 22.4}[/tex]
[tex]\frac {15.3}{22.4} \ mol \ He[/tex]
[tex]0.6830357143 \ mol \ He[/tex]
2. Convert Moles to GramsThe molar mass is the mass of 1 mole of a substance. These values are found on the Periodic Table as atomic masses, but the units are grams per moles. Look up the molar mass of helium.
He: 4.0026 g/molCreate another ratio using the molar mass.
[tex]\frac {4.0026 \ g \ He}{1 \ mol \ He}[/tex]
Multiply by the number of moles we calculated.
[tex]0.6830357143 \ mol \ He *\frac {4.0026 \ g \ He}{1 \ mol \ He}[/tex]
The units of moles of helium (mol He) cancel.
[tex]0.6830357143*\frac {4.0026 \ g \ He}{1 }[/tex]
[tex]2.73391875 \ g \ He[/tex]
3. RoundThe original measurement of volume has 3 significant figures, so our answer must have the same.
For the number we calculated, that is the hundredths place.
The 3 in the thousandths place to the right (2.73391875) tells us to leave the 3 in the hundredths place (2.73391875).
[tex]2.73 \ g \ He[/tex]
15.3 liters of helium gas is approximately 2.73 grams of helium.
list four quantum no. that defines energy state of the electron in hydrogen along with their possible values and explain their significance in terms of orbitals?
The number of joules required to heat one gram of a substance one degree Celsius is _____.
endothermic
temperature
exothermic
specific heat capacity
9.
Look at the following equation. What is the oxidizing agent? 3Mg + N2 ->Mg3N2
Answer:
In this reaction, nitrogen acts as the oxidizing agent. Mg is a reducing agent.
which orbital has the lowest energy
Answer:
s orbital
Explanation:
it has the lowest energy because
Paulis law state that orbitals with lower energy must be fill first before that of higher energy
and the s orbital is filled first
PLZ HELP Matthew wants to study how the body responds when the skin is broken. He learns that particles in the blood clump together at the site of the wound to stop the bleeding while the skin heals. Which of the following body systems is involved in carrying the blood to the site of the wound?
A. Cardiovascular
B. Skeletal
C. Respiratory
D. Muscular
Answer:
A, Cardiovascular system
cardiovascular system
Select the correct answer.
Which statement accurately describes natural selection?
A.
It ensures that 100 percent of beneficial traits will pass on to the next generation.
B.
It ensures that all individuals with harmful traits are unable to reproduce.
C.
Individuals with beneficial traits are more likely to successfully reproduce than those with harmful traits.
D.
Individuals are all equally likely to successfully reproduce, but the genome will mutate to erase harmful traits.
Answer:
D .
Explanation:
Individuals are all equally likely to successfully reproduce, but the genome will mutate to erase harmful traits.
The atomic mass of calcium is calculated by adding the mass (amount) of
A) Protons and Electrons
B) Protons and Neutons
C) Electrons and Neutons
D) Protons and Protons
Answer:
B. Protons and Neutrons
Answer:
Option"B" is correct.
MARK ME BRAINLISTS
A solution, such as pure water, with a pH of 7 contains which of the following?
a. Dissolved CO2
b. Equal amounts of hydrogen ions and hydroxide ions
c. Smokestack pollutants such as sulfur dioxide
d. Sodium hydroxide
Answer:
B
Explanation:
Pure water always has equal concentrations of hydrogen and hydroxide ions.
CaCO3 + 2HCl > CaCl2 + CO₂ + H₂O
Explanation:
This reaction is also known as double decomposition reaction.
HCl + CaCO3 + MgCO3 → H2O + H2 + CO2 + CaCl2 + MgCl2
how would you detect sulphur in organic compounds
Answer:
sodium fusion is changed to sodium sulphide if sulphur is present in the compound
What is the molarity of a sodium chloride solution that has 2.0 mol of
sodium chloride dissolved in 0.25 L of water? Answer to two
significant figures.
Answer:
[tex]\boxed {\boxed {\sf 8.0 \ M \ NaCl}}[/tex]
Explanation:
Molarity is a measure of concentration in moles per liter, therefore the formula is:
[tex]molarity= \frac{moles \ of \ solute}{lites \ of \ solution}[/tex]
There are 2.0 moles of solute or sodium chloride dissolved in 0.25 liters of water or solution.
moles of solute = 2.0 mol NaCl liters of solution = 0.25 LSubstitute these values into the formula.
[tex]molarity= \frac{ 2.0 \ mol \ NaCl}{0.25 \ L}[/tex]
Divide.
[tex]molarity=8 \ mol \ NaCl / L[/tex]
Molarity is measured in molars or M. 1 molar is equal to 1 mole per liter, so our answer is equal to 8 molars.
[tex]molarity= 8 \ M \ NaCl[/tex]
The original measurements of moles and liters have 2 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. There are no numbers to round, so we add a 0 in the tenths place.
[tex]molarity= 8.0 \ M \ NaCl[/tex]
The molarity of the solution is 8.0 M NaCl.
A block of dry ice (-40°C) is placed in contact with an ice cube (-10°C).
What will happen, assuming no chemical reactions occur?
O Heat will flow from the ice cube to the dry ice.
O Heat will flow from the dry ice to the ice cube.
O There is no way to tell without a thermometer
O No heat will flow.
Explanation:
Answer is that : no heat will flow
Answer:
Heat will flow from the ice cube to the dry ice
Explanation:
You mix the sample discussed in the previous two questions with another sample, which you know to be pure acetylsalicylic acid. You grind the mixture thoroughly with a mortar and pestle, and do a melting point determination on the mixed product. You now observe melting over a range of 127 to 133 C. Now what conclusions can you reach regarding the original product
Answer:
Having high melting point.
Explanation:
The original product has high melting point as compared to the mixture product because in the original product, the element is present in its pure state and we know that pure substances have high melting point as compared to mixture substances due to the presence of strong intercellular forces between them which is hard to break so that's why we can say that the original product has high melting point.
Teniendo en cuenta la imagen anterior responde las siguientes preguntas:
1. ¿Cuál es la tendencia general de la electronegatividad a lo largo de un periodo? a. Aumentar
b. Disminuir
c. La electronegatividad es igual en todos
d. no hay ninguna tendencia
2. Ordene los átomos siguientes de menor a mayor electronegatividad: Li, Ca, C y Se a. Li
b. Se
c. Ca
d. Se
3. ¿Cuál de los átomos siguientes es el que posee mayor potencial de ionización? a. P
b. Sb
c. As
d. N
4. De las siguientes definiciones, ¿Cuál se acerca más a lo que es la electronegatividad? a. Es la tendencia relativa que presenta un elemento a atraer hacia si electrones b. Es la tendencia relativa de un átomo en estado gaseoso a repeler los electrones c. es la carga negativa que representa una unión
d. es la diferencia entre el potencial de ionización y la afinidad electrónica de un elemento. rapido es para hoy
1. La tendencia general de la electronegatividad durante un período es que la electronegatividad aumenta durante un período
La opción correcta es a. Incremento
Razón
El número de electrones de valencia aumenta durante un período, por lo
que aumentar la tendencia del átomo a lograr la estructura de octeto
estable requiriendo atraer (cada vez menos a medida que avanzamos por
el período desde la izquierda a la derecha) compartieron electrones
cuando se forman enlaces, lo que aumenta electronegatividad
2. El orden de electronegatividad creciente es Li → Ca → C → Se
Razón
La electronegatividad aumenta a lo largo del período y disminuye en el grupo.
Las ubicaciones de los elementos dados son;
Litio, Li; Grupo 1 período 2 Calcio, Ca; Grupo 2 período 4 Carbono, C; Grupo 14 período 2 Selenio Se; Grupo 16 período 4Primero escribimos los elementos con los números de grupo más altos,
que son Se y C, después de lo cual tenemos Ca, luego Li, por lo tanto, en
orden creciente, obtenemos;
Li → Ca → C → Se
3. La opción correcta es d. N (nitrógeno)
Razón
El potencial de ionización representa la energía necesaria para eliminar un electrón de un átomo.
El potencial de ionización disminuye en un grupo y aumenta a lo largo de un período de izquierda a derecha.
Tenemos;
Fósforo, P; Grupo 15 período 3 Antimonio, Sb; Grupo 15 período 5 Arsénico, As; Grupo 15 período 4 Nitrógeno, N; Grupo 15 período 2Por lo tanto, el elemento con mayor potencial de ionización es aquel que se encuentra en la posición más alta en el grupo 15 entre los elementos dados, que es el nitrógeno, N
4. La opción correcta para la definición de electronegatividad es la opción (a);
un. Es la tendencia relativa de un elemento a atraer electrones hacia sí mismo.
Razón
La electronegatividad es la capacidad relativa de un elemento dado para atraer electrones compartidos hacia sí mismo.
Por lo tanto, la opción correcta es a. es la tendencia relativa de un elemento a atraer electrones hacia sí mismo
Obtenga más información sobre la electronegatividad y la energía de ionización aquí;
https://brainly.com/question/13961537
The process during which cells of the body harness energy from food consumed by a living organism is ______________________.
tính chất hoá học của Cu
Answer:
các oxit đồng khi nó tiếp xúc với không khí. nó phản ứng đặc biệt với oxy trong không khí (không phải hơi ẩm), và tạo ra nấm mốc
1125 J of energy is used to heat 250 g of iron to 55 °C. The specific heat capacity of iron is 0.45 J/(g·°C).
What was the temperature of the iron before it was heated?
55 °C
55 °C
35 °C
35 °C
45 °C
45 °C
20 °C
Answer:
45 °C.
Explanation:
From the question given above, the following data were obtained:
Heat (Q) = 1125 J
Mass (M) = 250 g
Final temperature (T₂) = 55 °C
Specific heat capacity (C) = 0.45 J/gºC
Initial temperature (T₁) =?
The initial temperature of the iron can be obtained as illustrated below:
Q = MC(T₂ – T₁)
1125 = 250 × 0.45 (55 – T₁)
1125 = 112.5 (55 – T₁)
Divide both side by 112.5
1125/112.5 = 55 – T₁
10 = 55 – T₁
Collect like terms
10 – 55 = –T₁
–45 = –T₁
Multiply through by –1
45 = T₁
T₁ = 45 °C
Therefore, the initial temperature of the iron is 45 °C
10. As electrons move through the electron-transport chain,
they lose energy, which is used to form
O A. NAD.
O B. ADP
O C. ATP.
O D. GBP
Answer:
C. ATP.
Explanation:
During the process of aerobic cellular respiration, energy is said to be released in three main stages: glycolysis, Krebs cycle and oxidative phosphorylation (electron transport chain). The electron transport chain produces the most energy and it involves the transfer of electrons through series of complex proteins.
As the electrons move through the individual complexes, energy is lost to form a proton gradient (H+). The proton gradient powers the synthesis of ATP from ADP as catalyzed by ATP synthase.
How much does the mass of 12.65-g sample of copper(II) nitrate hexahydrate decrease when heated?
Cuales son los tipos de yemas
hii pls help me to balance the equation thanksss
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
[tex]\boxed{\pmb{\color{gold}{\sf{2SO_{2}(g) + O_{2}(g)\dashrightarrow 2SO_{3}(g)}}}}[/tex]
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
[tex]\boxed{\sf {2SO_2\atop Sulphur\:DiOxide}+{O_2\atop Oxygen}\longrightarrow {2SO_3\atop Sulphur\:trioxide}}[/tex]
On reactant side:-Sulphur=2atomsOxygen=6atomsOn products side:-Sulphur=2atomsOxygen=6atomsHence balanced.
A car of 1200 kg is moving with a speed of 36 Km/hr. It is stopped by applying brakes withion with in 5 seconds. Calculate the amount of force required to stop the car.
Answer:
–2400 N
Explanation:
This is a physics question. However, the answer to the question is given below.
We'll begin by converting 36 Km/hr to m/s. This can be obtained as follow:
3.6 Km/hr = 1 m/s
Therefore,
36 Km/hr = 36 Km/hr × 1 m/s / 3.6 km/hr
36 Km/hr = 10 m/s
Thus, 36 Km/hr is equivalent 10 m/s.
Next, we shall determine the acceleration of the car. This can be obtained as follow:
Initial velocity (u) = 10 m/s
Final velocity (v) = 0 m/s
Time (t) = 5 s
Acceleration (a) =?
a = (v – u) / t
a = (0 – 10) / 5
a = – 10 / 5
a = –2 m/s²
Finally, we shall determine the force required to stop the car. This can be obtained as follow:
Mass (m) = 1200 Kg
Acceleration (a) = –2 m/s²
Force (F) =?
F = ma
F = 1200 × –2
F = –2400 N
NOTE: The negative sign indicate that the force is in opposite direction to the motion of the car.
Having a control group is important when doing an investigation why?
Answer:to help understand the stuff more
Explanation:
Why are the highest oxidation state of the transition metal stabilised in the oxide and fluoride compond?
Answer:
Following are the solution to the given question:
Explanation:
Its maximum oxidation zone is exceptionally stable and has the greatest ability to charge density, while fluoride and oxide ions are the largest particles with the largest durability of charge.
Or it might be assumed as oxygen and fluorine are the system particle atoms that have the highest electron number of metals.
Im sorry if its difficult to read
we dont talk about how I messed up my first question and jad to make another one because im slow
Answer:
A ball is thrown straight up from a rooftop 320 feet high. The formula below describes the ball's height above the ground, h, in feet, t seconds after it was thrown. The ball misses the rooftop on its way down and eventually strikes the ground. How long will it take for the ball to hit the ground? Use this information to provide tick marks with appropriate numbers along the horizontal axis in the figure shown.
h=-16t^2+16t+320
I need help on this question asap!
You are in a lab and you use 11.50 g of Na(s) to react with Cl(g). Below is the reaction that happens from this.
Na + Cl2 → NaCl
Your percent yield is 95%. From this info what is the actual yield?
Answer:
27.79 g to the nearest hundredth.
Explanation:
2Na + Cl2 ---> 2NaCl
Using the molar masses , the theoretical yield is:
46 g of Na yields 46 + 35.5*2 g NaCl
46 g ---> 117 g NaCl so
11.5 g ----> 117 * 11.5 / 46 g NaCl
But, as the yield is 90%
the actual yield is 0.95 * 117 * 11.5 / 46
= 27.79 g.
Although tom was a poor student, he studied very well
I’m screwed omg i totally forgot I have school today and forgot to do this someone help me rq I’ll brainlist plslsls be awake just make sure you write the word equation for each of the following metal oxidation reactions or if you can, also write a chemical equation below it. idrm bout that but it’ll be really nice if u did.
tried doing it and if ur one of the smart people that can do science unlike me surely u’ll help. ☺️
Answer:
Zn + O2 = ZnO
Mg + O2 = MgO
Cu + O2 = CuO
Al + O2 = Al2O3
Explanation:
