Answer:
a
Explanation:
a
Sodium-22 has a 2.605-year half-life. If you begin with 1.570 grams of Na-22, how many grams are left after 1.00 year?
Type the correct answer in the box. Express your answer to the correct number of significant figures.
Answer:
1.20 grams
Explanation:
Correct on edmentum/plato
Answer: 1.20 grams
Explanation:
WHAT HAPPENS WHEN ELECTRIC CURRENT PASSES THROUGH ACIDIFIED WATER.
Answer:
When an electric current is passed through acidified water, it decomposes to give hydrogen and oxygen gas. The hydrogen gas is obtained at the cathode and the oxygen gas is obtained at the anode
Which defines the word planet?
A. A large body that revolves around the Moon.
B. A large body suitable for life.
C. A large body that contains water and land.
D. A large body that revolves around the Sun.
Answer:
I think it's D cause one of the requirements for a planet is that it has to revolve around a star
A 25 Ω resistor has a voltage drop of 12 V across it. Calculate the current flowing through the resistor
Answer:
0.48
Explanation:
[tex]i = \frac{v}{r} [/tex]
because we are looking for I which is current we say
I = 12÷25 which is 0.48.
The current flowing through the resistor is 0.48 A.
What is resistor?The resistor is a length of wire which resists the flow of current.
According to Ohm's law, the potential difference is proportional to the current flowing in the circuit.
V =I R where R is the resistance.
Given is the resistance of resistor R = 25Ω and the voltage drop V =12 Volt, then the current through the resistor will be
I =V/R
I = 12/25
I =0.48 A
Thus, the current in resistor is 0.48 Amperes.
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Which of the following statements is correct about electrical insulators?
A. They do not contain any atoms.
B. Their protons are not allowed to move about freely.
C. The electrons are not able to move about freely.
D. They are good at conducting heat only.
Answer:
the answer is C in my opinion.. hope this might be helpful
A + 2 B + 4 C → products is known to be second order in A, first order in B and independent of the concentration of C. What is the value of the rate constant for this reaction if its rate is 0.783 M · s−1 when [A] = 5.00 M, [B] = 7.00 M, and [C] = 3.00 M? −2 −1 Answerinunitsof M ·s .
Answer:
4.47 × 10⁻³ M⁻² s⁻¹
Explanation:
Let's consider the following generic equation.
A + 2 B + 4 C → products
This reaction is known to be second order in A, first order in B and independent of the concentration of C (zero order in C). The rate law is:
rate = k × [A]² × [B] × [C]⁰
rate = k × [A]² × [B]
where k is the rate constant
When the rate is 0.783 M/s, [A] = 5.00 M, [B] = 7.00 M, and [C] = 3.00 M, the rate constant is:
k = rate / [A]² × [B]
k = 0.783 M/s / (5.00)² × (7.00) = 4.47 × 10⁻³ M⁻² s⁻¹
Which of the following correctly ranks the following bonds in order from most to least polar?
C-H, N-H, O-H, F-H
a)
O-H > F-H > N-H > C-H
b)
F-H > N-H > O-H > C-H
c)
C-H > N-H > O-H > F-H
d)
F-H > O-H > N-H > C-H
Answer:
O-H F-H N-Hy
Explanation:
C-H N-H O-H F-H
calculate the molecular weight of CaCO3.
Answer:
Explanation:
CaCO3 = 1*Ca + 1*C + 3*O
=1*40 + 1*12 + 3*16
=40 + 12 + 48
=100 amu
Briefly explain why adding insulation to an attic helps reduce heating costs.
Answer:
Insulation reduces the exchange of heat through a surface such as a wall, attic, duct or roof. In a well-insulated home, less warm air escapes from the house during the winter, and less cool air escapes during the summer, reducing the amount of energy needed for heating and cooling
The metric system is also known as the
Answer:
THE answer is all of above
Explanation:
A. 2 pts: In terms of conservation of mass, what were the results of each experiment (which one conserved mass and which one did not)?
B. 4 pts: PROVIDE a SPECIFIC explanation for "why" the results in both videos were different.
. 2 pts: Discuss differences in the experimental steps between the two videos (for example what was done in video one that was not done in
video two, why would this make a difference in conserving mass?)
• 2 pts: Look at both chemical equations (below for convenience), what difference in the type of products would have contributed to the
differences in why one conserved mass and one did not?
REACTION 1: Pb(NO3)2 (aq) + 2K1 (aq) --> 2KNO3 (aq) +Pölz (s)
• REACTION 2: NaHCO3(s) + CH3COOH(aq) → CO2(g) + H2Om + CH3COONa(aq)
Answer:
dftdffdgxrdfdrdxxxxdddddddddddddeeertdffddy
Chemistry 1 question please help!! 10 points
Answer:
3
Explanation:
its the 3 one it is
Una reacción química es un proceso en el cual se produce un cambio químico, es decir, se consume una o más sustancias a medida que se forman una o más sustancias nuevas.
Answer:
Para ser mas exactos una reaccion quimica es donde los reactivos se transforman en productos.
Explanation:
Durante las reacciones quimicas, ocurren ciertas transformaciones que hace que se tome o se libere energia del medio, generando que los reactivos de la reaccion, es decir los compuestos iniciales, en un determinado espacio y tiempo bajo ciertas condiciones de presion y temperatura exactas se transformen en productos.
Para la quimica, la misma cantidad de materia que se encuentra en los reactivos se mantendra en los productos, es por eso que cada reaccion quimica debe respetar las reglas de la estequiometria y estar balanceadas a la perfeccion.
4. What is a renewable resource? List some examples.
Answer:
Renewable resources include biomass energy (such as ethanol), hydropower, geothermal power, wind energy, and solar energy. Biomass refers to organic material from plants or animals. This includes wood, sewage, and ethanol (which comes from corn or other plants).
five examples of renewable resources
Solar energy.
Wind energy.
Geothermal energy.
Hydropower.
Bioenergy.
I hope it help you
Answer:
The most popular renewable energy sources
currently are
Solar energy
Wind energy
Hydro energy
Tidal energy
Geothermal energy
Biomass energy
What is the pH of a solution?
O A. A measure of the strength of the acid
B. A measure of the buffering ability of the solution
O c. A measure of the hydrogen gas concentration
O D. A measure of the acidity of the solution
Answer:
D. A measure of the acidity of the solution
Explanation:
pH is a measure of how acidic or basic a solution is, and is measured on a scale from 0-14, where 7 is neutral, anything less than 7 is acidic, and anything more than 7 is basic.
Joelle is a manager at a construction company, and she is interested in the chemistry behind the materials they use. She has begun studying the materials used to fill walls. She knows that to keep the temperature inside a room steady the material must be a thermal insulator, and she predicts that materials should not be acidic or else they would dissolve too easily in water.
Which of these is a molecular ingredient that could be used in a wall-filling material ?
C27H36N2O10
Na6Ba6
NeNa
HCl
Answer:
a
Explanation:
A molecular ingredient that could be used in a wall-filling material is C₂₇H₃₆N₂O₁₀, is not a good thermal insulator, hence option A is correct.
The big molecule C₂₇H₃₆N₂O₁₀ is a poor thermal insulator. Since NeNa is a relatively reactive chemical, it would probably dissolve in water far too quickly. The acidic molecule HCl would dissolve far too quickly in water.
Not a good thermal insulator is C₂₇H₃₆N₂O₁₀. It is a big molecule composed of a lot of hydrogen atoms. Since hydrogen atoms are excellent heat conductors, they would be ineffective in stopping heat from passing through a material used to fill a wall.
Thus, the option (A) C₂₇H₃₆N₂O₁₀ is correct.
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What happens when an unstable nucleus undergoes radioactive decay?
A. Electrons change energy levels to balance the nucleus.
B. Energy is absorbed by the nucleus to make it more stable.
O C. Particles or electromagnetic radiation are emitted.
D. The nucleus increases in mass through radioactive decay.
How many moles of sodium are in its 85 g?
Answer:
22.98977
Explanation:
don't worry about that
Explanation:
85 g Na × (1 mol Na/22.9898 g Na)
= 3.7 mol Na
Which of the following best describes an electron transition?
A. An electron gains or loses energy and moves between continuous
energy levels.
B. An electron gains or loses charge and changes into a proton or a
neutron.
C. An electron gains or loses energy and moves between quantized
energy levels.
D. An atom gains or loses an electron and becomes an ion.
Answer:
A. An electron gains or loses energy and moves between continuous
energy levels.
Which is the best reason to carry out scientific research on climate change?
A. To help people prepare for the future
O B. To create jobs for scientists
C. To elect better-informed politicians
D. To win political debates
Which is the best reason to carry out scientific research on climate change?
A. To help people prepare for the future
B.To create jobs for scientists ☑️C. To elect better-informed politicians
D. To win political debates
Answer:
to create jobs for scientists
Which of the following could possibly be true about a strong acid? (Check all that apply:).
It will completely dissociate (break apart) when dissolved in water.
It could have a pH of 6
It could have a pH of 13
Only a few of the acid molecules will dissociate (break apart).
It could have a pH of 2.
It could have a pH of 9
Answer:
it could have a pH of 2 it will completely dissociate when dissolved in waterIf the pH = 6.5, what is the [H+]? *
3.16 x 10-7
3.16 x 10-6
O
3.16 x 10-5
Answer:
Key Concepts
The hydrogen ion concentration in a solution, [H+], in mol L-1, can be calculated if the pH of the solution is known.
pH is defined as the negative logarithm (to base 10) of the hydrogen ion concentration in mol L-1 pH = -log10[H+] ...
[H+] in mol L-1 can be calculated using the equation (formula): [H+] = 10-pH
More items...
Explanation:
Answer:
[tex]pH = - log[H {}^{ + } ] \\ 6.5 = - log[H {}^{ + } ] \\ [H {}^{ + } ] = {10}^{ - 6.5} \\ [H {}^{ + } ] = 3.16 \times {10}^{ - 7} \: mol {dm}^{ - 3} [/tex]
How are liquid water, ice, water different from each other?
Answer: In liquid water, water molecules are moving faster. They are still close together, but they are no longer stuck in a rigid pattern as they are in ice. Water molecules in liquid water are constantly sliding past and bumping into each other; they keep moving from one place to another.
Answer:
they are different forms
Explanation:
ice is solid
and water is liquid
they also have different densities
What is the delta H when 72.0 grams H2O condenses at 100.00C?
Here are some constants that you MAY need.
specific heats heat of fusion heat of vaporization
H2O(s) = 2.1 J/g0C 6.01 kJ/mole 40.7 kJ/mole
H2O(L) = 4.18 J/g0C
H2O(g) = 1.7 J/g0C
2930 kJ
163 kJ
-163 kJ
-2930 kJ
Answer: The value of [tex]\Delta H[/tex] is -163 kJZ
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
We are given:
Given mass of water = 72.0 g
Molar mass of water = 18 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of water}=\frac{72.0g}{18g/mol}\\\\\text{Moles of water}=4mol[/tex]
Calculating the heat released for the condensation process:
[tex]\Delta H=n\times \Delta H_{(vap)}[/tex] ......(2)
where,
[tex]\Delta H[/tex] = amount of heat released
n = number of moles of water = 4 moles
[tex]\Delta H_{(vap)}[/tex] = specific heat of vaporization = -40.7 kJ/mol
Negative sign represents the amount of heat released.
Putting values in equation 2:
[tex]\Delta H=4mol\times (-40.7kJ/mol)=-163kJ[/tex]
Hence, the value of [tex]\Delta H[/tex] is -163 kJ
Find the surface area of a square pyramid with side length 5 cm and slant height 4 cm.
Answer:
h = height
s = slant height
a = side length
P = perimeter of base
e = lateral edge length
r = a/2
V = volume
L = lateral surface area
B = base surface area
A = total surface area
Explanation:
Volume of a square pyramid:
V = (1/3)a2h
Slant Height of a square pyramid:
By the pythagorean theorem we know that
s2 = r2 + h2
since r = a/2
s2 = (1/4)a2 + h2, and
s = √(h2 + (1/4)a2)
This is also the height of a triangle side
Lateral Surface Area of a square pyramid (4 isosceles triangles):
For the isosceles triangle Area = (1/2)Base x Height. Our base is side length a and for this calculation our height for the triangle is slant height s. With 4 sides we need to multiply by 4.
L = 4 x (1/2)as = 2as = 2a√(h2 + (1/4)a2)
Squaring the 2 to get it back inside the radical,
L = a√(a2 + 4h2)
Base Surface Area of a square pyramid (square):
B = a2
Total Surface Area of a square pyramid:
A = L + B = a2 + a√(a2 + 4h2))
A = a(a + √(a2 + 4h2))
Please help, only a couple of days left!!!
Answer:
the heat from the universe during the big bang
a.k.a.
ITS A
Explanation:
the universe is still expanding, so what is gonna be used to create that new matter that's expanding the universe? energy and heat from the beginning of the universe! the universe started off as this point that was probably smaller than a quantum foam and infinite heat and started expanding from there
Por qué razón se fomenta la inmigración Europea?
Hola aquí va la respuesta!
Se fomentó la inmigración europea porque la economía no era buena y vinieron a Paraguay para mejorar su situación.
Hola aquí va la respuesta!
Se fomentó la inmigración europea porque la economía no era buena y vinieron a Paraguay para mejorar su situación.
Can anyone solve this for me please.
I appreciate anyone that is helping me with these questions
Which two laws were discovered by Antoine Lavoisier and Joseph Proust?
Consider the following intermediate chemical equations.
CH2(g) →C(s) + 2H2(g)
CC1.(g) → C(s) +2012(g)
H2(g) +C12(g) → 2HCl(9)
ΔH, = 74.6 kJ
ΔH2 = 95.7 kJ
ΔΗ =
ΔHg =-92.3 kJ
What is the enthalpy of the overall chemical reaction CH (g) +4012(g) → CCl4(h)+ 4HCl(g)?
Answer: The enthalpy of the overall chemical equation is -205.7 kJ
Explanation:
Hess's law is defined as the law which states that the total amount of heat absorbed or released for a given chemical reaction will remain the same whether the process occurs in one step or several steps.
In this law, a chemical equation is treated as an ordinary algebraic expression that can be added or subtracted to yield the required overall equation.
The enthalpy change or heat of the overall reaction is the summation of the enthalpies or heats of the intermediate reactions involved in the process.
The given overall chemical equation follows:
[tex]CH_4(g)+4Cl_2(g)\rightarrow CCl_4(g)+4HCl(g);\Delta H^o_{rxn}[/tex]
The intermediate equations for the above reaction are:
(1) [tex]CH_4(g)\rightarrow C(s)+2H_2(g);\Delta H_1=74.6 kJ[/tex]
(2) [tex]CCl_4(g)\rightarrow C(s)+2Cl_2(g);\Delta H_2=95.7kJ[/tex]
(3) [tex]H_2(g)+Cl_2(g)\rightarrow 2HCl(g);\Delta H_3=-92.3kJ[/tex]
According to Hess law, the enthalpy of the reaction becomes:
[tex]\Delta H^o_{rxn}=[1\times (\Delta H_1)] + [1\times (-\Delta H_2)] + [2\times (\Delta H_3)][/tex]
Putting values in above expression, we get:
[tex]\Delta H^o_{rxn}=[1\times (74.6)] + [1\times (-95.7)] + [2\times (-92.3)]\\\\\Delta H^o_{rxn}=-205.7kJ[/tex]
Hence, the enthalpy of the overall chemical equation is -205.7 kJ
