Answer:
Take the weighted average of the individual isotopes.
Explanation:
63
C
u
has
69.2
%
abundance.
65
C
u
has
30.8
%
abundance.
So, the weighted average is
62.93
×
69.2
%
+
64.93
×
30.8
%
=
63.55
amu
.
If we look at the Periodic Table, copper metal (a mixture of isotopes but
63
C
u
and
65
C
u
predominate) has an approximate atomic mass of
63.55
g
⋅
m
o
l
−
1
, so we know we are right.
What must occur for a change to be a chemical reaction? a. There must be a change in chemical properties. b. There must be a change in physical properties. c. The change must involve a change in mass. d. The change must involve a change in volume. Please select the best answer from the choices provided A B C D Mark this and return
Answer:
A. There must be a change in chemical properties.
At least 2 or 3 atoms must change for it to be considered chemical. There must be some type of reactants that will change this. Otherwise, it's not a chemical reaction.
Hope this helps!
What contribution did J.J. Thomson make to the development of atomic theory?
A said that atoms are solid masses
B showed that electrons surround a dense nucleus
C found that atoms are made of smaller particles
D proposed that atoms contain electric fields
Answer:
C found that atoms are made of smaller particles
Explanation:
Thomson's discovery of the electron proved the existence of subatomic particles.
The contribution that J. J. Thomson makes to the development of atomic theory is as follows:
He found that atoms are made of smaller particles.Thus, the correct option for this question is C.
What is Atomic theory?Atomic theory may be defined as a scientific theory that demonstrates that each matter on the earth's surface s composed of particles called atoms. Atoms bear specific physical as well as chemical properties.
In this scientific theory, J. J. Thomson makes his contribution by stating that atoms are made of smaller particles. Apart from this, he was also well-known for the discovery of electrons. But he failed in obtaining the exact position of electrons.
This kink of the actual position of electrons was solved by Ernest Rutherford by stating that electrons surround a dense nucleus.
Therefore, atoms are made of smaller particles is the contribution that J.J. Thomson make to the development of atomic theory.
To learn more about J. J. Thomson, refer to the link:
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a. Magnesium and Fluorine
b. Sodium and Fluorine
c. Sodium and Oxygen
d. Aluminium and Iodine
2. Write the chemical formula using the 4-step method for:
a) Magnesium sulphide,
b) Magnesium Fluoride,
c) Hydrogen Bromide and
d) Iron (III) Oxide.
Answer:
1)
a. MgF₂
b. NaF
c. Na₂O
d. AlI₃
2)
a. MgS
b. MgF₂
c. HBr
d. Fe₂O₃
What does this represent about the type of change
happening in the container?
Theresa creates an experiment where she mixes two
red-colored substances together in a container and
observes the solution slowly changing from red to blue
for the next eight minutes. The solution becomes
completely blue after eight minutes.
O A chemical change started immediately and finished
at eight minutes.
O A non-chemical change started immediately and
finished at eight minutes.
O A chemical change occurred at four minutes.
O A non-chemical change occurred at four minutes.
Answer:
A
Explanation:
A chemical change started immediately and finished at eight minutes
Answer:
The answer is
A.) A chemical change started immediately and finished
at eight minutes.
Explanation:
Polymers have very __________ molecules. Which word completes the sentence?
Answer:
Large
Explanation:
Polymers have very large molecules called macromolecules
why does water have such a high melting point?
which is the correct molecular structure for carbon dioxide
=> It is centrosymmetric and linear .
√so in that case carbon dioxide has no electric dipole.Explanation:
The central carbon atom is joined to two oxygen atoms by covalent double bonds
TRUE OR FALSE:
Most living organisms are composed of cells
Answer:
True
Explanation:
Everything is made up of matter, therefore everything (living) is made up of cells.
This statement is True.
All living organisms are composed of one or more cells. Cells are what make up our bodies. Cells are the basic unit of life.
Which is the smallest particle into which a compound can be broken down
and still remain the same compound?
A) atom
B) mixture
C) element
D) molecule
Answer:
molcule
Explanation:
Which of the following is a sign that a chemical change is taking place?
Select one:
A.
a substance melting at high heat
B.
an object breaking into pieces
C.
a blue solid dissolving in water and changing the water to a blue colour
D.
an offensive odor emitting after two liquids are mixed
Answer:
C. a blue solid dissolving in a water and changing the water to a blue colour
Explanation:
hello people ~
From which parts of the plant cotton and jute are obtained?
Answer:
in cotton is obtained from it's flower part while jute is obtained from it's stem
pls answer ASAP pls & ty aha
when you change the shape of a ball of clay, you are changing the amount of mass , true or false
Answer:
if you change the shape wouldn't it still have the same mass and volume because the density remains the same? so I think it is false
Answer:
False
Explanation:
when you change the shape of the ball of clay, it does not change mass or volume, your not adding more just changng it's form. You can only change it's mass or volume by adding more or breaking it into less.
URGENT  Please I need help answering these two questions ASAP
A balloon of helium was put in the freezer at -23°C. Its volume at this temperature was 2.5 liters. It was removed from the freezer. Eventually, it reached a temperature of 177°C. What would its volume be at this temperature? (Neglect any force used to stretch the rubber balloon.)
Answer:
4.5 L
Explanation:
From Charles law;
V1/T1 = V2/T2
Where;
V1= initial volume = 2.5 L
T1 = initial temperature = -23°C + 273 = 250 K
V2 = final volume = unknown
T2 = 177°C +273 = 450 K
Making V2 the subject of the formula
V2 = V1 T2/T1
V2 = 2.5 × 450/250
V2 = 4.5 L
Scientists examine the light spectra from distant stars to determine if the size of the universe is changing. Why do astronomers believe the size of the universe is changing?
options:
The red shift indicates that distant galaxies are moving away from each other.
The red shift indicates that distant galaxies are moving towards each other
The blue shift indicates that distant galaxies are moving away from each other
The blue shift indicates that distant galaxies are moving towards each other
Answer: A
Explanation:
Red shifting occurs when objects move away from each other. You can think of the light wave being "stretched." A stretching of the wave causes a higher wavelength, and less energy, which are the characteristics of red light.
A nitrogen gas collected in a tube has a volume of 0.86 mL, a temperature of 316.48 degrees kelvin, and a pressure 1.17 atm. Two days later, the volume of the nitrogen was 1.06 mL but the pressure did not change. What was the temperature two days later
Give two examples of an ionic compound?
A mixture of three noble gases has a total pressure of 1. 25 atm. The individual pressures exerted by neon and argon are 0. 68 atm and 0. 35 atm, respectively. What is the partial pressure of the third gas, helium? Use P subscript T equals P subscript 1 plus P subscript 2 plus P subscript 3 plus ellipses plus P subscript n. 0. 22 atm 0. 33 atm 1. 03 atm 2. 28 atm.
The partial pressure of the third gas, helium will be [tex]P_h=0.22\ atm[/tex]
What is partial pressure?According to Dolton's law of partial pressure if the mixture of gases exists in a container then the total pressure exerted by the gas will be the sum of the partial pressure of each case.
Now from the question, it is given
The total pressure of the three noble gases [tex]P_t=1.25\ atm[/tex]
The individual pressure of Neon= 0.68 atm
The individual pressure of argon=0.35 atm
The partial pressure of the third gas will be:
[tex]P_t=P_A+P_N+P_H[/tex]
[tex]P_H=P_T-P_A-P_N[/tex]
[tex]P_H=1.25-0.68-0.35=0.22\ atm[/tex]
Hence the partial pressure of the third gas, helium will be [tex]P_h=0.22\ atm[/tex]
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Answer:
a. .22
Explanation:
When an object heats up , it
Answer:
gains thermal energy. the thermal energy is kinetic energy at the molecular scale, and friction and stuff
For each of the following sets of atoms, rank them from lowest to highest
electronegativity.
a. N, Li, C
b. O, C, Ne
c. B, P, Si, o
d. Ca, F, Mg, P
e. He, S, F
Answer:
E
Explanation:
Well fluorine has the highest electronegativity.
Mikayla says that air is an element since it has oxygen in it. Jose says that air is a mixture because each part of air keeps its properties. Grant says that both Mikayla and Jose are wrong, because air is a compound. Who is correct and why? Group of answer choices
Answer: Jose is correct because air is a mixture of gases ( both elements and compounds).
Explanation:
An element consist of only one type of atom and a compound made up of 2 or more types of elements joined together ( by ionic or covalent bonds).
Whereas air around us is a mixture of gases (both elements and compounds) like nitrogen, oxygen, argon, and carbon dioxide, and very small amounts of other gases and water vapors
Hence, Jose is correct because air is a mixture of gases ( both elements and compounds).
the table which shows some information about four organic compounds P, Q, R and S and answer the question that follow.
1.Which Homologous series does C3H8 belong to ?Give its general formula.
2. Predict the chemical formula of the next two members of this homlogous series.
3. Based on the information given above, state one chareceristics of the homologous series
Answer:
1. Alk
2.The molecular formula of two members of a homologous series are C 3 H 4 and C 6 H 1 0
3.
same functional group
physical properties
formula compounds are the same
Alkanes are simple saturated hydrocarbons with its first member as methane.
Alkanes have low melting and boiling points.
What are alkanes?Alkanes are saturated hydrocarbons whose names end with -ane which have its simplest and first member as methane.
The homologous series to which the compound C3H8 belongs to is alkanes.
Alkanes have the general molecular formula given below:
[tex]C_nH_{2n + 2}[/tex]
[tex]The \: next \: two \: member \: of \: the \: series \: are \: C_7H_16 and C_8H_18[/tex]
The alkanes usually have low melting and boiling points.
Therefore, alkanes are simple saturated hydrocarbons.
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A cube with sides 3cm.Its mass is 54g. will it sink or float
Answer:
It will sink.
Explanation:
Density of water=1gm/cc (In CGS)
Volume of cube=l^3 =3^3= 27cc
Mass of cube =54gm
Density of cube=M/V =54/27 =2gm/cc
Here, density of cube is greater than that of water. So, the cube sinks.
Mercury, Venus, and Earth are the three planets closest to the sun. Would their combined distance from the sun be greater or less than the distance from the sun to Neptune? Show your work and justify your answer.
Answer: No, see below for explanation
Explanation:
Distance from Sun to Mercury = 57.91 million km
Distance from Sun to Venus = 108.2 million km
Distance from Sun to Earth = 149.6 million km
So their combined distance from the sun is = ( 57.91 + 108.2 + 149.6 ) million km = 315.71 million km
Distance from Sun to Neptune = 4.495 billion km
Convert this distance to millions = 4.495 * 1000 million km
= 4495 million km
It is clear that combined distance of Mercury, Venus & Earth from the Sun is much less than the distance from the Sun to Neptune
Matter in a _______ has ______volume and ______ shape.
Answer:
Matter in a solid state has definite volume and definite shape.
Explanation:
The solid matter has the property of definite shape and volume because the molecules present in a solid are tightly packed so the molecules do not flow and there is no change in volume and force of attraction between the molecules will be very high that shows rigidity of molecule.
If a sample of gas with pressure 450kPa at 225°C what will its
pressure be at 25°C if the volume does not change?
Answer: 269.3 kPa
Explanation:
Since the volume does not change, the formula: P/T = P/T can be used.
However, all temperatures must first be converted into kelvin, which can be done like this: 225 Celsius + 273 = 498 K; and 25 Celsius + 273 = 298 K.
Now, plug into the formula: 450 / 498 = P / 298 → Cross multiply and divide to get:
P = 269.3 kPa :)
How many zeros are in the measurement 0.000040200 m are significant?
Answer:
It’s 3
Explanation:
PLEASE HELP ASAP DUE INNA COUPLE MINUTES ILL MARK BRAINLIEST JUST HELP QUCIK
Answer: This occurs becuase the wall is more positively charged than the ballon. As the wall and balloon come in contact the balloon sticks due to the rule that opposites attract meaning positive attracts negative. The negatively charged balloon attracts the electrons in the paper because it's positive since positive attracts negative.
Explanation:
.
2. Bacteria are prokaryotes.
What does this mean?
Which statement about hydrogen bonds is true?
They are the only force that allows a gecko to climb up glass.
They are the weakest of the intermolecular forces.
They are much stronger than intramolecular forces.
They help water striders walk on water by creating surface tension.
Answer:
The help water striders walk on water by creating surface tension.
Answer:
D)
Explanation:
Trust