Answer:
[tex]2.55 \times {10}^{24} [/tex]
atoms
Which element do all organic compounds contain?
nitrogen
silicon
carbon
phosphorous
Scientists who study objects in space (astronomers) often scan the sky using devices called radio telescopes. What can you conclude about these devices?
Question 10 options:
They send radio broadcasts out to distant stars and planets.
They pick up the radio waves emitted by stars, galaxies, and other objects in space..
They are less powerful than optical telescopes (telescopes that use visible light).
They can detect unltraviolet radiation
Predict the sign of delta H for water condensing. Is this reaction spontaneous?
A) + and spontaneous
B) - and uncertain
C) + and uncertain
D) - and spontaneous
Answer:
A + and spontqneous
Explanation:
i hope this helps.
The enthalpy change of condensation of water is negative and here the entropy change also negative and the process is nonspontaneous.
What is enthalpy change?The enthalpy change of a reaction or a phase change is the change in heat energy absorbed or evolved. The change in enthalpy is dependant on the nature of process as well on temperature of the system.
Condensation of water is the change of its liquid state into solid state. Thus water freezes to form ice. In this process, the system is getting more ordered structure in the solid state and thus, the entropy of the system decreases means the entropy change is negative.
Now, when converting liquid to solid heat is released by the system. Hence, enthalpy change, delta H is negative. A process becomes spontaneous only f its Gibbs energy is negative.
Here we have both negative entropy and enthalpy so make Gibbs energy negative higher temperature is needed.
Condensation of a substances is taking place at very low temperature and thus gibbs energy become positive. Therefore the process is nonspontaneous.
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When referring to immunity, what does the term innate imply?
the mechanism will provide defense against many different types of pathogens
the mechanism will develop based upon exposure to specific pathogens
the mechanism will be built-in and present at birth
the mechanism will be acquired over an individual's lifetime
Answer:
Innate, or nonspecific, immunity is the defense system with which you were born. It protects you against all antigens. Innate immunity involves barriers that keep harmful materials from entering your body.
To what volume should 0.0667 mol of KCl be diluted in order to prepare a 0.250 M solution?
To prepare 0.250 M solution, the 0.0667 mol of KCl should be diluted up to 266.8mL
StoichiometryFrom the question,
We are to determine to what volume the KCl should be diluted, in order to prepare 0.250 M solution
From the formula,
Numer of moles = Concentration × Volume
Then, we can write that
[tex]Volume= \frac{Number\ of\ moles}{Concentration }[/tex]
From the given information,
Number of moles = 0.0667 mole
Concentration = 0.250 M
Then,
[tex]Volume = \frac{0.0667}{0.250}[/tex]
Volume = 0.2668 L
Volume = 266.8 mL
Hence, to prepare 0.250 M solution, the 0.0667 mol of KCl should be diluted up to 266.8mL
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Helium is an example
of a gas because
A. helium does not take the shape of its
container.
B. helium particles are very randomly spaced
and moving freely.
C. helium particles are electrically charged.
D. helium cannot change its size or shape to fit
its container
Answer:
B
Explanation:
The particles move freely
Based on the electron configuration of the two atoms, predict the ratio of metal cationic (+) atom to nonmetal anionic (-) atom in the compound.
magnesium 1s22s22p63s2
bromine 1s22s22p63s23p64s23d104p5
a. 1:1
b. 1:2
c. 2:1
d. 3:1
The ratio of metal cationic (+) atom to nonmetal anionic (-) atom in the compound is 1:2.
What is electron configuration?The term electron configuration shows the arrangement of electrons in an atom. We have the configurations of the atoms as follows;
magnesium - 1s22s22p63s2
bromine - 1s22s22p63s23p64s23d104p5
We can see that the catio is Mg^2+ and the anioin is Br^- hence the ratio of metal cationic (+) atom to nonmetal anionic (-) atom in the compound is 1:2.
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Which is the best definition of rate-determining step?
a) an elementary step that often occurs in the reaction mechanism
b) the elementary step that limits how fast the overall reaction proceeds
c) an elementary step that is used to derive a rate law
d) the unimolecular step in a reaction mechanism
Answer:
The correct answer is B. Give me Brainliest
Who is credited with arranging the periodic table?.
Russian chemist Dmitri Mendeleev
i need help ..........
Answer:
E
Explanation:
The problem with choices A B C D is that the molecular balance numbers are incorrect. E is the only one correctly balanced. For example in A is balanced as
3Mg + 2H2O ===> 3Mg0 + 2H2
The Mg's are correctly balanced.
So are the hydrogens. But take a look at the 0xygens. There are 2 on the left and 3 on the right. The equation is not balanced correctly. B and C have the same problem. One of elements is not balanced correctly.
what mass of CO2 gas occupies 6.7L at 2 atm and 245k
Which of the following helps explain why experiments involving speed and velocity are important? (1 point)
Experiments involving speed and velocity are important because they have not been investigated much and scientists still do not fully understand how speed and velocity are related
Experiments involving speed and velocity are not important because they have already been thoroughly investigated by scientists and there is nothing more to learn.
Repeated experiments with airplanes and how their velocity changes as a result of environmental conditions like wind can help scientists develop a model for flight paths and launch times to
minimize fuel usage
O Repeated experiments that change motivational foods for tortoises on tracks can help scientists determine preferred eating habits
The statement that explain the important of experiment with speed and time is
Repeated experiments with airplanes and how their velocity changes as a result of environmental conditions like wind can help scientists develop a model for flight paths and launch times to minimize fuel usage.
What is an experiment?An experiment is a scientific procedure or technique carried out in a place to discover or test the validity of something.
Velocity refer to the rate of change of body's position and direction in respect to time.
Speed is the distance travel by an object in respect to time.
Therefore, The statement that explain the important of experiment with speed and time is
Repeated experiments with airplanes and how their velocity changes as a result of environmental conditions like wind can help scientists develop a model for flight paths and launch times to minimize fuel usage.
Learn more about experiment below.
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24. When density decreases, the number of
molecules in a volume
A increases.
B decreases
C stays the same
D varies
___ discovered the actual force of g
I think the answer will be:
Sir isaac newton.
What do the following organic chemicals have in common glyphosphate, lindane, 2,4-d, chlordane
Glyphosphate, lindane, 2,4-d, chlordane are organic compound that have chlorine in common.
What is Organic compound?Organic compound are group of chemical substance that have carbon and hydrogen atoms in which the bonds are covalently linked together.
Therefore, Glyphosphate, lindane, 2,4-d, chlordane are organic compound that have chlorine in common and these chemicals are use as herbicides that is kill weeds, or to kill insects or pests because of chlorine present in it.
Learn more about organic compounds here.
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Which statement best describes what happens to the carbon dioxide produced by humans?.
Draw a structural formula for the more stable carbocation intermediate formed in the reaction shown.
A carbocation is a carbon atom that bears a positive charge. The most stable carbocation here must be a secondary carbocation .
What is a carbocation?A carbocation is a carbon atom that bears a positive charge. These species pften pccur as intermediates in a chemical reaction and can be detercted spectroscopically.
The most stable carbocation here must be a secondary carbocation hence, the structural formula for the more stable carbocation intermediate formed in the reaction is shown in the image attached.
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As the pressure on a given sample of a gas increases at constant temperature, the mass of the sample.
which two products are formed when lipids are broken down
Answer:
Fatty acids and glycerol.
Explanation:
I hope this helps! :)
(The process is called lipolysis by the way)
Consider the following balanced equation:
2KCIO3 → 2KCI + 302
How many grams of O2 will be obtained by decomposing
98.1 grams of KClO3?
A. 38.4 grams
B. 17.1 grams
C. 76.8 grams
D. 25.6 grams
7. Complete the following equations. [2]
a. Sodium + Water ______________________ + Hydrogen
b. Copper carbonate + Sulfuric acid _____________________ +_____________ + Carbon dioxide
c. Sulfur + _________________ Sulfur dioxide
Answer:
Sodium + water --› Sodium hydroxide + hydrogen gas
Copper carbonate + sulphuric acid --› Copper sulphate + water + carbondioxide
Sulphur + Oxygen --› Sulphur dioxide
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A sample of iron having a mass of 93.3 g is heated to 65.58 oC and is placed in 75.0 g of water raising the temperature of the water from 16.95 o C to 22.24 o C. Find the specific heat capacity for this iron sample. (Specific Heat of Water (C) = 4.184 J/go C)
Answer:
0.271J/g°C
Explanation:
mass of iron=93.3g
∆°C=65.58
mass of water=75g
C of water=4.184
∆°C=22.4-16.95=5.29°C
mc∆°C of iron = mc∆°C of water
93.3×C×5.29=75×4.184×5.29
C=75×4.185×5.29/93.3×65.58
C=0.271J/g°C
Which substances are contained in saliva and tears to break down pathogens?
enzymes
acids
oils
sweat
Answer:
A. Enzymes
Explanation:
Enzymes are in our saliva and tears. They help break down pathogens and the cell wall of bacteria.
I hope it helps! Have a great day!
Muffin~
Answer:
A. Enzymes.
Explanation:
Enzymes break down things and they are in both our saliva and tears.
I hope it helps! Have a great day!
.-.
A sample of an ideal gas has a volume of 2.22 L at 284 K and 1.11 atm. Calculate the pressure when the volume is 1.95 L and the temperature is 305 K.
Answer: 1.36 atm
Explanation:
What are the most likely dates of the full moon
Answer:
C
Explanation:
Answer C Full moon occurs approx 2weeks after new moon
What type of change will alter the makeup of the elements or molecules of a substance?
A. chemical
B. physical
C. reactor
40 points please help me very easy!
Answer:
it is charles's law
Explanation:
volume does matter with pressure
What is the average mass for
Answer:
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pls help me to answer this:(
Answer:
How do one confess feelings to her if he is introvert?
Can someone pls tell me the answer to these 2 fill in the blanks I will surely mark him as the brain list answer