Answer: im pretty sure its D
Explanation:
Which of these statements are true? Select all that apply. The Delta. Hf for Br2(I) is 0 kJ/mol. The Delta. Hf for He(I) is 0 kJ/mol. The Delta. Hf for Hg(I) is 0 kJ/mol. The Delta. Hf for Cl2(g) is 0 kJ/mol. The Delta. Hf for N2(I) is 0 kJ/mol.
The enthalpy of formation of liquid mercury and gaseous chlorine are zero because the substance are in their standard state.
The standard state of a substance is the form in which it is found under standard conditions. This include a pressure of 1 atm, a temperature of 298 K and a a concentration of 1 M.
The enthalpy of formation of a substance in its standard state is 0 KJ/mol. The following substances has ΔHf of 0 kJ/mol.
ΔHf of Hg(I) is 0 kJ/mol. ΔHf of Cl2(g) is 0 kJ/molLearn more: https://brainly.com/question/13164491
HELP ME PLZZZ
SMNSNSNS
D
D
D
D
D
D
D
D
D
D
Answer:
#1 is C, #2 is D, #3 is A
Explanation:
A sample of nitrogen gas at STP has a volume of 65.8 L. What is the mass of the gas?
A)
82.3 g
B) 41.18
2.94 g
07
0.210 g
E
0.1058
Answer:
B
Explanation:
HELP ME PLEASE HURRY
The characteristics of two different types of reactions are shown below:
Reaction A: Electrons are gained by the atoms of an element.
Reaction B: Protons are lost by the atom of an element.
Which statement is true about the atoms of the elements that participate in the two reactions?
Their identity changes in both Reaction A and Reaction B.
Their identity changes in Reaction A but not in Reaction B.
Their identity changes in Reaction B but not in Reaction A.
Their identity remains the same in both Reaction A and Reaction B.
Answer:
D is correct
Explanation:
Answer:
A
Explanation:
Electrons are gained by the atoms. There is no change in the nucleus of the atom and the number of protons remains identical.
How many atoms are in 11.5g of Hg
how does one determine a molecular formula from the epirical formula
Answer:
C
Explanation:
Would an alkaline earth metal make a good replacement for tin in a tin can?
Answer:
Definitely not. This is because the alkaline earth metal [basically group 2 elements] are reactive and will react with the contents of the can, contaminating it.
No, alkaline earth metals would not be a good replacement for tin in a tin can because alkali from alkaline earth metals react with tin and release hydrogen.
What are alkaline earth metals?Alkaline earth metals are present in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
They are called alkaline earth metals because their hydroxide and oxides are highly alkaline. Their metal oxides are found in the earth's crust.
These metals have 2 electrons in their outer shell, and they are highly reactive, so they will react with the tin in a tin can.
Thus, alkali from alkaline earth metals react with tin and generate hydrogen, hence they would not make an acceptable replacement for tin in a tin can.
To learn more about alkaline earth metal, refer to the below link:
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Select the correct answer. In which situation is chemical energy being converted to another form of energy? A. a lamp plugged into the electric grid B. a fluttering flag C. a floating wooden log D. a burning candle
Answer:
D. A burning candle. (chemical energy into energy of heat and light, i.e. thermal and wave)
Explanation:
comment and tell me if it right.
The situation in which chemical energy being converted to another form of energy is a burning candle.
So, option D is correct one.
What is chemical energy?The energy produce by the chemical reaction is called chemical energy.
Example: burning of candle.
Give the example of energy conversion.When lamp plugged into electric grid then electrical energy is converted into light energy.When candle is burn then chemical energy is converted into light energy.No energy takes place during a fluttering flag and a floating wooden log.learn more about chemical energy,
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good and bad effects of changes in materials in the environment
Answer:
Composting, recycling, technological development, water cycle and photosynthesis are changes that have good effects. Some changes have bad effect like pollution and destruction of habitat and lose of lives.
Explanation:
hope it helps
why are we always at the center of a rainbow? and why can we see a rainbow?
Answer:
the sun is directly behind your head
Explanation:
The reason why we can see a rainbow is caused by sunlight and atmospheric conditions
Use the chemical equation to complete the activity.
4Fe + 3O2 → 2Fe2O3
Iron (Fe) reacts with oxygen (O2) to form iron oxide. A scientist adds 15.4 grams of Fe to 3.6 grams of O2 to start the reaction. All of the iron and oxygen react to form iron oxide. Explain in detail how you can determine how many grams of iron oxide will be produced.
Use the law of conservation of matter in the explanation.
Answer:
14.54 g Fe2O3
Explanation:
The first step would be to balance the equation but since it's already balanced we don't have to worry about that.
Through the balanced equation, you can find the stoichiometry of the reaction, that is:
4 moles of Fe, react with 3 moles of O2, to produce 2 moles of Fe2O3
Chemistry (accurately stoichiometry) is all about ratios and proportions. The balanced equations gives you the standard ratio by which moles are produced.
So the next step (shown in the paper), is to convert the grams that are giving you in Moles, and you do this by dividing the number of grams given by the molar mass of the substance. The molar mass is the number of grams by which you can find exactly 6.022x10²³ molecules (one mole) of one specific substance.
15.4 g of Fe= 0.28 mol Fe
3.6 g of O2= 0.11 mol O2
Now that you have the quantity of moles, what you need to do is to look for the limitant reactant.
In a balanced equation, the number of moles in the reactants are the rules and they're gonna react completely with each other. If you want x quatity of reactants to react completely, then you will have to respect the proportion to the ratio given in the balanced equation.
But you will rarely follow the proportion so there will usually be a reactant that's gonna be limiting the reaction and one that is in excess. And how do you find this? Well, the easiest way to do it is:
Dividing the number of moles obtained by x element the coefficients of that element in the balanced equation. The one that has the smallest ratio, is the limitant reactants.Since the limitant reactant is gonna be limiting the reaction, all the stoichiometric procedures should be calculated through it, and in this case, the limitant reactant is O2.
But then how to establish the stoichiometric rule to find the number of Iron oxide (III) that's being produced?
Look back to the stoichiometry of the reaction:
To produce 2 moles of Fe2O3, you need 3 moles of O2.
But you have 0.11 mol O2.
Then establish a factor of conversion (shown in the picture)
The result is 0.07 mol of Fe2O3, but you need the answer in grams so you find the molar mass of Fe2O3 and then multiply it by the number of moles (0.07)
The answer is 14.54 g of Fe2O3
CHEMISTRY IS ALL ABOUT PROPORTIONS :D
which reaction is an oxidation-reduction reaction?
Answer:
pl
saponification palmitate
which option can be classified as a pure substance
A. solution
B. compound
C. homogeneous mixture
D. heterogeneous mixture
Answer:
B. compound
Explanation:
A pure substance can be an element, which consists of only one type of atom and cannot be broken down by a chemical change, or a compound, which consists of two or more types of atoms.
True or false? The empirical formula of a compound is the simplest formula that shows the numerical relationship of the elements in the compound.
Answer:
True
Explanation:
the empirical formula usually shows us the atoms' symbols and then how much of them are present in this certain compound. For example there is H2O
question: the diagram below shows the major parts of the digestive system.
what part of the digestive system is labeled by the number 1?
A.
small intestine
B.
esophagus
C.
stomach
D.
mouth
Answer:
I got it Right in Study Island
Explanation:
The bowl of fruit has a mass of 2.2 kg.
What net force must act on the bowl of fruit to make it accelerate to the right
at a rate of 4.4 m/s2? (Hint: Use F = ma.)
A. F = 9.68 N right
B. F = 9.68 N left
C. F = 6.60 N left
D. F= 6.60 N right
Taking into account the Newton's second law, the correct answer is option A. F = 9.68 N right
In first place, acceleration in a body occurs when a force acts on a body.
Newton's second law states that a force will change the speed of an object because the speed and/or direction will change. These changes in velocity are called acceleration.
So, Newton's second law defines the relationship between force and acceleration mathematically. This law says that the acceleration of an object is directly proportional to the sum of all the forces acting on it and inversely proportional to the mass of the object
Mathematically, Newton's second law is expressed as:
F= m×a
where:
F = Force [N] m = Mass [kg] a = Acceleration [m/s²]In this case, you know:
F= ? m= 2.2 kg a= 4.4 m/s²Replacing in Newton's second law:
F= 2.2 kg× 4.4 m/s²
Solving:
F= 9.68 N
Finally, As the bowl of fruit accelerates to the right, the correct answer is option A. F = 9.68 N right
Learn more about the Newton's second law:
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Which of the following giant covalent structures is a good conductor of electricity?
a) polythene
b) diamond
c) graphite
d) silicon dioixide
What is the correct formula
for tin(II) chloride dihydrate?
the answer is A. SnCl2 . 2H2O
I will give thanks, profile thanks, brainliest and 5 star
Answer: E.) C2N2H8
Explanation:
Answer:
E ) C2N2H8
Explanation:
How many grams of iron are in 350 mg of iron? *
O A. 3.50 g
O B.0.350 g
O C.35.09
Answer:
It s B because 350 mg= 35.0cg=3.50dg=0.350
Answer:
its 0.350 letter B
Explanation:
im pretty sure you divide the mass value by 1000 to get you answer.
A student makes an aqueous solution of sodium hydroxide. Which statement correctly identifies the two ions present in the solute of this mixture?
A. The sodium ion is positive, and the hydroxide ion is negative.
B. The sodium ion is neutral, and the hydroxide ion is neutral
C. The sodium ion is positive, and the hydroxide ion is positive.
D. The sodium ion is negative, and the hydroxide ion is positive.
Answer:
A. Na+ OH-
Explanation:
positive and negative ions form bonds because positive and negative attract
Consider the van deemter equation. why does increasing the flow rate reduce the contribution of longitudinal diffusion to total plate height?
Answer:
Why does increasing the flow rate reduce the contribution of longitudinal diffusion to total plate height? Increasing the flow rate decreases the time the solute resides in the column, resulting in less diffusional broadening.
Explanation:
An ion is:
Select one:
a.
An atom with an extra neutron.
b.
An atom or molecule with an electrical charge.
c.
The outermost shell of an atom.
What was boyle’s most famous discovery about gases?
Answer:
Boyle's most famous discovery had to do with how the pressure and volume of gases relate, either this or he discovered the volume of a gas decreases with increasing pressure...
Explanation:
...
what are subatomic particles?
Explanation:
a particle smaller than an atom (e.g., a neutron) or a cluster of such particles (e.g., an alpha particle).
Liquids have a definite volume when poured into a container. What does this mean?
Answer:
A solid has definite volume and definite shape, a gas has neither definite volume nor definite shape, and as said in the question, a liquid has a definite volume but no definite shape.
What this means is that even though liquid molecules can slide past each other and move to fill up the space they are in (this means that liquids have no definite shape), they keep their volume. That is, liquids have consistent, unchanging volume.
Hopefully that's helpful! :)
What would be the partial pressure of nitrogen, PN2, in a room in which the total air pressure was 0.987 atm?
This problem is providing describing a room in which air has a total pressure of 0.987 atm and the partial pressure of nitrogen is asked, turning out to be 0.746 atm.
In such a case, we can start by looking at the provided table, which shows the composition of dry air in mass basis, which means we must convert the composition of nitrogen to mole fraction by knowing that the average molar mass of air is 28.9647 g/mol, and thus, we infer that the mole fraction of nitrogen in air is about 0.755 according to:
[tex]x_{N_2}=\frac{0.781*14.0067g/mol*2}{28.9647g/mol} =0.755[/tex]
Then, we recall the Dalton's law version that relates total pressure, partial pressure and mole fraction written for nitrogen:
[tex]P_{N_2}=x_{N_2}P[/tex]
Finally, we plug in the previously calculated mole fraction and the total pressure of air to obtain:
[tex]P_{N_2}=0.755*0.987 atm\\\\P_{N_2}=0.746atm[/tex]
Learn more:
(Gas laws) https://brainly.com/question/8511562(Dalton's law) https://brainly.com/question/14119417Which dosage form is a semisolid preparation that contains very small solid particles that are suspended in a liquid
A GEL is a semisolid preparation that contains very small solid particles that are suspended in a liquid. A gel always contains an agent (e.g., agarose) that provides stiffness to the preparation.
A gel is a semisolid preparation that contains a gelling agent which provides stiffness to the preparation.
The gelling agent can be, for example, agarose (this gelling agent is used to prepare gels in electrophoresis).
In an agarose gel, agarose molecules are organized into three-dimensional (3D) structures similar to pores, which allow the passage of DNA fragments during electrophoresis.
Learn more about agarose gel here:
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At room temperature, all the metalloids are solids, while most nonmetals are
Answer:
at their own state.
That leaves only five elements: carbon, phosphorus, sulfur, selenium, and iodine, which are all non-metals and are solid at room temperature.
what do you think will happen to the kidneys if any of these parts were damaged?
Answer:
When your kidneys are damage waste products and fluid can build up in your body. That can cause swelling in your ankles nausea weakness poor sleep and shortness of breath. so without treatement the damage can get worse and your kidney may eventually stop working.