Answer:
0.491 mol NaCl
Explanation:
Convert from grams to moles using the molar mass of NaCl:
28.7 g NaCl x 1 mol NaCl/58.44 g NaCl = 0.491 mol NaCl
The molar mass (58.44 g) can be found from adding the molar masses of the individual elements (Na and Cl); the g NaCl will cancel out (dimensional analysis), leaving you with mol NaCl.
Astronomers send probes to other planets to take pictures of their surfaces. An astronomer thinks that briny water flows on Mars because he noticed certain features in one picture of Mars. Which method did the astronomer
use to form this hypothesis?
1.reading scientific literature
2.making careful observations
3. analyzing a natural experiment
4. conducting a controlled experiment
Answer: the answer is B
Explanation:
what type of boundary is formed when two continental plates converge, buckle and push up into mountain rages?
Answer: Convergent Boundary
Explanation:
Two plates converge at one point
To determine the freezing point depression of a LiCl solution, Toni adds 0.317 g of LiCl to the sample test tube along with 20.5 mL of distilled water. Determine the concentration, in molality, of the resulting solution. MW of LiCl is 42.394 g/mol Density of H2O is 0.9982 g/mL
Answer:
0.365 m
Explanation:
The definition of molality is:
molality = moles of solute / kg of solventFirst we calculate the moles of the solute, LiCl. We do so using its molar mass:
0.317 g ÷ 42.394 g/mol = 7.48x10⁻³ molThen we calculate the mass of the solvent, water. We do so using its density:
20.5 mL * 0.9982 g/mL = 20.5 g20.5 g / 1000 = 0.0205 kgFinally we calculate the molality of the solution:
7.48x10⁻³ mol / 0.0205 kg = 0.365 mHow many liters of N2 gas are in 2.4 moles at STP?
Answer:
any gas takes up 22.4L per mole so 2.4*22.4=53.76
Explanation:
In 2.4 moles at STP, 53.79 litres of N2 gas are present.
What are moles?Moles are defined as the amount of substance of a system that contain the same number of entities as the number of atoms in 12g of carbon 12.
What is STP?STP is defined as the standard temperature and pressure. At STP, as system has s temperature of zero degree centigrade or 273 Kelvin and the pressure is 1 atm.
PV= nRT
P= 1 atm
V= ?
n= 2.4 moles
R= 0.0821 L atm /K/mol
1 x V = 2.4 x 0.0821 x 273
V = 53.79 litres
Hence, 53.79 litres of N2 gas is present in 2.4 moles at STP.
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Steel is an alloy of iron and carbon. The addition of carbon to iron enhances which of the following properties of iron metal?
O A hardness
O B. malleability
O C. ductility
O D. softness
Answer:
The answer should be A. Adding carbon to iron makes it tougher and stronger.
The addition of carbon atom to iron metal, enhances the property of hardness of metal.
What is alloy?Alloy is a compound which is formed by the mixture of two or more than two metals with different properties to make a new compound with better properties.
When we add carbon atom in the iron metal, it deviates the crystal lattice property of iron and makes it more harder. So, the content of carbon in the iron is directly proportional to the hardness of iron metal.
Hence, option (A) is correct i.e. hardness.
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Which equation illustrates conservation of mass?
O 1 H2 + 1 O2 + 2 H2O
O 1 H2 + 1 2 + 1 H2O
O 1 H2 + 1 Cl2 +1HCI
O 1 H2 + 1 Cl2 + 2HCI
Answer:
1H₂ + 1Cl₂ → 2HCl
Explanation:
The reaction that illustrates the law of conservation of mass is shown below:
1H₂ + 1Cl₂ → 2HCl
According to the law of conservation of mass "in a chemical reaction, matter is neither created nor destroy but atoms are rearranged".
Therefore, we are expected to the end a reaction with the amount of substance we start with.
Element H Cl
Reactants 2 2
Products 2 2
We see that number of atoms on both sides are the same.
what is this for questions 2
Answer:
I think is D
Explanation:
PLEASE MARK ME AS BRAINLIEST
There are many important laws and theories in science. Which of the following is a law of science?
A living thing is made of at least one cell.
ОО
An atom is made of electrons orbiting a nucleus.
Gravity will pull two objects toward each other.
Natural selection will change species to fit their environments.
Answer: the answer is C
Explanation:
Answer:C
Explanation:I got it correct
A gas stream contains 18.0 mole% hexane and the remainder nitrogen. The stream flows to a condenser, where its temperature is reduced and some of the hexane is liquefied. The hexane mole fraction in the gas stream leaving the condenser is 0.0500. Liquid hexane condensate is recovered at a rate of 1.50 L/min. N2 C6H14(v) (5.00 mole%) N2 C6H14(v) (18.0 mole%) Liquid condensate 1.50 L C6H14 (l)/min CONDENSER (a) What is the flow rate of the gas stream leaving the condenser in mol/min
Answer:
the flow rate of the gas stream leaving the condenser is 71.9 moles/min
Explanation:
Given the data in the question and the figure below;
N2 BALANCE
(100% - 18%) × ( mole rate in ) = ( 100% - 5%) × ( mole rate out)
0.82 × ( mole rate in ) = 0.95 × ( mole rate out)
mole rate in = 0.95 × ( mole rate out) / 0.82
mole rate in = 1.1585365853 × ( mole rate out)
now;
HEXANE BALANCE
0.18 × ( mole rate in ) = 0.0500 × ( mole rate out) + condensate --- equ 1
but condensate = 1.5 L/min × ( density of hexane ) × 1/molar mass of hexane
we know that;
density of hexane is 0.6548 g/mL
and molar mass of hexane is 86.18 g/mol
so,
condensate = 1.5 L/min × ( 0.6548 g/mL × 1000 mL/L ) × ( 1/86.18 g/mol)
condensate = 11.3970758876
now lets substitute into equation 1
0.18 × ( mole rate in ) = 0.0500 × ( mole rate out) + condensate
⇒ 0.18 × ( 1.1585365853 × ( mole rate out) ) = 0.0500 × ( mole rate out) + 11.3970758876
⇒ 0.208536585354(mole rate out) = 0.0500( mole rate out) + 11.3970758876
⇒ 0.208536585354(mole rate out) - 0.0500( mole rate out) = 11.3970758876
⇒ 0.158536585354(mole rate out) = 11.3970758876
mole rate out = 11.3970758876 / 0.158536585354
mole rate out = 71.889247 ≈ 71.9 moles/min
Therefore, the flow rate of the gas stream leaving the condenser is 71.9 moles/min
If a substance has a density of 2.545g / mL how many grams would the substance weigh if the sample has a volume of 122.1 mL?
Answer: 310.7 grams
Explanation:
Multiply the two values so the units of mL cancel and you get grams
2.545*122.1 = 310.7 grams
A first order reaction has a rate constant of 0.924 at 25 oC. Given that the activation energy is 89.8 kJ/mol, calculate the rate constant at 33.3 oC.
Answer:
[tex]k_2=2.46[/tex]
Explanation:
Hello!
In this case, according to the Arrhenius equation for variable temperature:
[tex]ln(\frac{k_2}{k_1} )=-\frac{Ea}{R}(\frac{1}{T_2} -\frac{1}{T_1} )[/tex]
Given the temperatures to be computed in kelvins and the activation energy, we obtain:
[tex]ln(\frac{k_2}{0.924} )=-\frac{89800J/mol}{8.314J/(mol*K)}(\frac{1}{306.45K} -\frac{1}{298.15K} )\\\\ln(\frac{k_2}{0.924} )=0.981\\\\k_2=0.924*exp(0.981)\\\\k_2=2.46[/tex]
Best regards!
What is the mass of 2.90 L of O2 gas at STP
Answer:
4.16 g
Explanation:
Volume, V = 2.90 L
STP mans standard temperature and pressure
T = 273 K
P = 1 atm
Mass = ?
Using the ideal gas equation;
PV = nRT
where R = General gas constant = 0.082 L atm mol-1 K-1
n = PV / RT
n = 1 * 2.90 / (0.082 * 273)
n = 2.90 / 22.386
n = 0.130 mol
The relationship between moles and mass;
Mass = number of moles * Molar mass
Mass = 0.130 mol * 32 g/mol
Mass = 4.16 g
Answer:4.14
Explanation:just answered the question
According to the law of conservation of matter, we know that the total number of atoms does not change in a chemical reaction and thus mass is conserved. This
is part of a chemical reaction: hydrogen plus oxygen yields water. Can you complete this model? Reorganize the reactants in order to complete the product side
of the reaction
Your answer:
There is another answer choice with 4 reactants
Answer:
the answer is second option. with 2 models
Explanation:
2H2 + O2 gives 2H2O
so there's two models
What is the name of the sugar that is created
through photosynthesis?
Nopetose
Glucose
Sucrose
Blooptose
:D
Answer:
Glucose!!
Explanation:
Also keep in mind that the actual sugar produced from photosynthesis is C6H12O6, which is the basis for glucose as well as other complex molecules
Answer:
Glucose
Explanation:
photosynthesis uses the energy from the light to convert carbon dioxide molecules which makes glucose
What makes an atom a good conductor?
What is the percent by weight (w/w%) of sugar in soda? Assume the average mass of sugar in soda is 23.0 g and the total mass is 370.0 g.
The percent by weight (w/w%) of sugar in soda : 6.216%
Further explanationGiven
mass of sugar = 23 g
total mass = 370 g
Required
the percent weight
Solution
%weight = (mass of solute : mass of solution) x 100%
solute = sugar
solution = solvent + solute = water + sugar
percent weight of sugar in soda :
= (23 : 370) x 100%
= 6.216 %
It’s a test and only need 2 more problems!!!! Thank you and Appreciate it!!!
Answer:
the molar mass of propane (c3H8) is
12*3+1*8
=36+8=44
Describe the motion of a person NOT wearing a seat belt if the car stops suddenly
A the person and car will stop together
B the person will stop faster than the car because they are lighter
C the car will stop and the person will keep moving forward
D the car will stop and the person will speed up
Answer:
c the car will stop and the person will keep moving forward
Explanation:
Because since the person has no force apllied they will keep moving until force is apllied.
what are three things that are considered a chemical change
Answer:
Color change, precipitation, bubbling
Explanation:
Chemical change changes the chemical composition and undergoes a process in which it results as a new substance.
If 80% of the moths are dark and you have 80 moths, how
many would be dark??
Answer:
the answer is 64 moths are dark
the atomic number of potassium is 19. How many electrons does this element have?
Answer:
Potassium is an element that has 19 electrons
__Fe + ___ Cl2 --> ___FeCl3
The coefficient on iron for this equation is:
A 4
B 2
C 1
D 3
I’ll give you a lot of points and mark you brainlist if you awnse all 3
Answer:
Magma
Volcanic glass
Granite and pumice
Explanation:
Answer:
Magma,
Volcanic Glass,
Granite and Pumice,
Lava
Explanation:
Examine the diagram of the cell cycle.
Which label identifies the stage in which the DNA is copied and the cell grows?
A-W
B-X
C-Y
D-Z
Explanation:
i think w is the required answer
Pls answer this ASAP thank you
Answer:
The anwer is not D the anwer is A
Explanation:
ANSWER ASAP
2. The figure shows the first three rows, or periods, of the periodic table. Suppose the fourth period is added. How many orbits will the Bohr models in the fourth period have? How many electrons will an atom in Group 1 in the fourth period have?
Answer:
19 electrons in first group of 4th period element that is potassium K
Explanation:
compute the mass-specific enthalpy change associated with Nz that is undergoing a change in state from 400 k to 800 k
Answer:
The correct answer is "430 kJ/kg". A further explanation is given below.
Explanation:
The given values are:
T₁ = 400 k
T₂ = 800 k
The average temperature will be:
= [tex]\frac{T_1+T_2}{2}[/tex]
= [tex]\frac{400+800}{2}[/tex]
= [tex]600 \ k[/tex]
From table,
At 600 k the [tex]C p[/tex] will be = 1.075
Now,
⇒ The specific enthalpy = [tex]Cp(T_2-T_1)[/tex]
⇒ [tex]\Delta h=1.075 (800-700)[/tex]
⇒ [tex]=430 \ kJ/kg[/tex]
8. Neil pogo sticks from his locker to his science class. He travels 8 m east then 8 m west
back to his locker. What distance did he cover? What was his displacement?
Answer:
12
Explanation:
The distance that Neil Pogo travels is 16 meters. While the displacement is Zero (0).
What is Displacement?Displacement may be defined as the distance traveled by an object from the initial point to the final point. It is a vector quantity and has a direction and magnitude. In a more simple sense, it is known to be the alteration of the position of the object.
According to the question,
The total distance covered by Neil Pogo = 8 m east then 8 m west = 16 meters.
But according to the definition of displacement, his total displacement was zero. This is because the distance between his initial point and the final point is zero.
He returned back to the same place indicating his zero displacements.
Therefore, the distance that Neil Pogo travels is 16 meters. While the displacement is Zero (0).
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According to the following reaction, how many moles of calcium chloride will be formed upon the complete reaction of 27.9 grams of calcium hydroxide with excess hydrochloric acid? calcium hydroxide (aq) + hydrochloric acid (aq) calcium chloride (aq) + water (l) moles calcium chloride
Answer: 0.377 moles of calcium chloride will be formed.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} Ca(OH)_2=\frac{27.9g}{74g/mol}=0.377moles[/tex]
The balanced chemical reaction is:
[tex]Ca(OH)_2+2HCl\rightarrow CaCl_2+2H_2O[/tex]
According to stoichiometry :
As 1 mole of [tex]Ca(OH)_2[/tex] give = 1 mole of [tex]CaCl_2[/tex]
Thus 0.377 moles of [tex]Ca(OH)_2[/tex] give =[tex]\frac{1}{1}\times 0.377=0.377moles[/tex] of [tex]CaCl_2[/tex]
Thus 0.377 moles of calcium chloride will be formed upon the complete reaction of 27.9 grams of calcium hydroxide with excess hydrochloric acid
2. The boiling point of a solution containing 6.4 g of the hormone adrenaline in 360 g of
CCl4 is 0.49 K higher than the boiling point of pure CC14. Calculate the molar mass of
adrenaline. (K = 5.02 kg K/mol).
Answer:
MM = 182.13g/mol
Explanation:
Hello!
In this case, since the boiling point elevation is computed via:
[tex]\Delta Tb=i*m*K[/tex]
Thus, since adrenaline is nonionizing, we can compute the molality at first instance:
[tex]m=\frac{\Delta Tb}{i*K}=\frac{0.49K}{1*5.02kg\frac{K}{mol} } \\\\m=0.0976mol/kg[/tex]
Now, we compute the the moles of adrenaline in 360 g (0.360 kg) of CCl4:
[tex]n=0.0976mol/kg*0.360kg\\\\n=0.0351mol[/tex]
Finally, the molar mass:
[tex]MM=\frac{6.4g}{0.0351mol}\\\\MM=182.13g/mol[/tex]
Best regards!
