Answer:
It's a double displacement reaction.
A published hypothesis:
A: does not need to be tested
B: becomes a scientific law
C: should be tested by the scientific community
D: is accepted by the scientific community
Answer:
C
Explanation:
I hypothesis needs to be tested to know whether it is true or not. Here is the definition:
A supposition or proposed explanation made on the basis of *limited evidence as a started point for further investigation*
Brainliest if answered correctly
How many Calcium (CA) atoms are in carbon tetrachloride
Answer:
What atoms are present in carbon tetrachloride?
There is 1 carbon, and 4 chlorine atoms (or chloride ions if you want to get technical). Tetra means 4 in Greek.
hope that helps❤
Answer:
there are no calcium atoms of n carbon tetrachloride
A metal is treated with dilute hydrochloric
acid in a test tube. A burning match stick is brought
near the mouth of the test tube, but no sound is
heard.
Explanation:
There are certain metals that are less reactive compared to standard hydrogen electrode.
So, such metals do not release hydrogen gas in a reaction with dilute acids.
Examples of such metals are:
copper,silver,gold,platinum,mercury.
Answer:
A burning match stick is brought
near the mouth of the test tube, but no sound is
heard. That means hydrogen gas is not released in this reaction and the metal may be a less reactive metal and it is one among the above list of metals.
Using dobereiner's triads, what conclusion could have been made about magnesium
Answer:
Triads were groups of 3 elements with similar chemical and physical properties. Beryllium, magnesium, and calcium are all earth alkalis found in the earth
Explanation:
Mole concept
Calculate the number of iodine atoms in 4.50g of iodine gas
Answer:
0.017g/mol
Explanation:
according to the mole concept to calculate the number of moles of a substance you use the formula
number of moles= mass/molecular mass
=4.5g/254g/mole
=0.017moles
I hope this helps and sorry if it's wrong
When a vacancy exists in an inner electron shell of an atom (as a result of photoelectric effect, Compton scattering, or bombardment by other electrons), the energy liberated when this vacancy is filled, instead of emerging from the atom as fluorescent radiation, can be transferred to another electron of the atom, thereby ejecting the electron. Such an emitted electron is called a(n) _____ electron
Answer:
The answer is "Auger".
Explanation:
The Auger effect is an effect size when the vacancy of even an atom throughout the inner shell was complemented by the release of even an electron from the same atom. Whenever a central electron is lost, a higher energy level electron can drop into the void and release energy, which can be the result.
A process which is unfavorable with respect to enthalpy, but favorable with respect to entropy Group of answer choices could occur at high temperatures, but not at lower temperatures. could not occur regardless of temperature. could occur at any temperature. could occur at low temperatures, but not at higher temperatures. none of the above
Answer:
could occur at any temperature.
Explanation:
The spontaneity of a reaction is what determines whether the reaction will occur or not. A spontaneous reaction occurs easily.
The spontaneity of a reaction is predicted by the sign of ∆G.
When ∆G is positive, the reaction is not spontaneous. When ∆G is negative, the reaction is spontaneous.
Note that;
∆G= ∆H - T∆S
Where;
∆H = Change in enthalpy
∆S = Change in entropy
T= temperature
If ∆H is unfavourable and ∆S is favourable, the reaction can proceed at all temperatures because ∆G will always be negative.
It should be noted that a process that is unfavorable as regards to enthalpy, but favorable with respect to entropy could occur at any temperature.
Enthalpy(∆H) serves as amount of internal energy that a compound has, entropy( ∆S) on the other hand serves as intrinsic disorder within the system.
However, spontaneity of a reaction determines likely hood of occurrence of a reaction, when the process is spontaneous, it makes the reaction to occurs easily.
We can conclude that whenever enthalpy is unfavourable and entropy of a system is favourable, then the spontaneity will be negative and the reaction will occur at any temperature.
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Name five metal which are both dilute and memorable? class 10
Analysis of an ore of calcium shows that it contains 13.61 g calcium and 21.77 g oxygen in a 46.28-g sample. Calculate the percent composition of this compound.
Answer:
29.41% of Calcium and 47.04% of Oxygen
Explanation:
The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.
The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:
13.61g / 46.28g * 100 = 29.41% of Calcium
And percent composition of Oxygen is:
21.77g / 46.28g * 100 = 47.04% of Oxygen
can u plz solve it n send the answer
1. Cl2 + H2O → HOCl + HCl
2. Tooth decay starts when when the pH of the mouth is lower than 5.5. Tooth enamel is made up of calcium phosphate and it is one of the hardest substances of the body. But it is corroded when the pH is less than 5.5. The bacteria of our mouth produce acids by degradation of sugar and food particles remaining in our mouth after eating food.
3. Fluorine salts are added in toothpaste to protect our teeth from tooth decay. Fluorine salts are mildly basic, so they neutrelise the acid in our mouth that leads to tooth decay.
4. Tincture of iodine is iodine, pottasium iodide and sodium iodide dissolved in ethanol. Iodine acts in an antiseptic manner by destroying microbial proteins and DNA.
5. Tincture of iodine is clear and reddish brown liquid.
how many Molecules and atoms of the product 2H2O+ O2
Answer:
A water molecule is composed of two hydrogen atom and one oxygen atom but you can't simply take two hydrogen atom stick them onto an oxygen atom
how do i calculate the concentration of a certain solution
Answer:
Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.
How do the substances compare?
in which instrument of the following the washer works works as a valve? a)syringe b)hydraulic garage lift c)air pump d)watre pump
Answer:
A
Explanation:
The instrument in which the washer works as a valve is A ; syringe
Each instrument listed have a washer and a valve, but of all the instruments listed above the instrument that its washer works also as a valve is the syringe.
A syringe is composed of a thin tube and a thinner hollow needle attached to the end of the thin tube. the needle is used and take in liquids and also expel liquids from the syringe ( i.e. washer and valve )
hence the instrument that its washer also functions as a valve is the syringe.
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2. Nitric oxide contains 46.66% nitrogen and 53.34% oxygen. Water contains 11.21% hydrogen and 88.79% oxygen. Ammonia contains 17.78% hydroger and 82.22% nitrogen. Use these data to verify the law of reciprocal proportions.
Answer:
The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other
The compounds formed includes;
1) Nitric oxide, NO
Nitrogen = 46.66% × 30.01 = 14
Oxygen = 53.34% × 30.01 = 16
2) Water, H₂O
Hydrogen = 11.21% × 18.01528 = 2
Oxygen = 88.79% × 18.01528 ≈ 16
3) Ammonia, NH₃
Hydrogen = 17.78% × 17.031 ≈ 3
Nitrogen = 82.22% × 17.031 ≈ 14
The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8
The ratio of nitrogen to hydrogen in ammonia = 14:3
The ratio in which hydrogen and oxygen combine with nitrogen = 3/16
The ratio of hydrogen and oxygen combine with each other in water = 2/16
Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions
Explanation:
A liquid that occupies a volume of 8.2L has a mass of 5.6kg. What is the density of the liquid in kg/L
Answer:
0.68
Explanation:
This is because the formula for finding density is mass/volume. Therefore the equation becomes 5.6/8.2 giving you 0.68
calculate the mass of magnesium needed to make 25g of magnesium oxide
mark brainliest of correct xx
Answer:
15g
Explanation:
First, you need to correct the answer to the previous question. The percentage by mass of Mg in MgO =
Mg = 24.3 amu
O = 16.0 amu
The total mass of MgO = 40.3 amu
To calculate the percent composition of Mg:
% = 24.3/40.3 x 100
% = 60
To calculate the mass of Mg needed to make 25g of MgO:
x/25g = 60%/100%
100x = (25)(60)
100x = 1500
x = 15g
BJECTIVE TYPE QUESTIONS
Fill in the blank spaces by choosing the correct words from the words given in list.
List : composition, heat, chemical, photosynthesis, physical
1. Heating of zinc oxide is a
change.
2. Burning of coal is a
change.
3. There is a change in state and
during a chemical change.
4. Plants make their food by the process of
5.
energy is generally given out or absorbed during a chemical change
Answer:
1.Physical change
2. Chemical change
3. Heat
4.photosynthesis
5. composition
Which of the following statements about periodic trends is true?
O both electronegativity and atomic radius decrease from bottom to top and from left to right on
the periodic table.
O both electronegativity and ionization energy increase from bottom to top and from left to right
on the periodic table.
O both atomic radius and ionization energy increase from bottom to top and from right to left on
the periodic table.
O electronegativity, ionization energy and atomic radius all decrease from bottom to top and from
left to right on the periodic table.
both electronegativity and ionization energy increase from bottom to top and from left to right
on the periodic table.
Consider the reaction. 2HF(g)—H2(g)+F2(g). What is the value of Keq for the reaction expressed in scientific notation
Answer:
A). 2.1 × [tex]10^{-2}[/tex]
Explanation:
Given reaction,
2[tex]HF[/tex] (g) ⇄ [tex]H_{2}[/tex] (g) + [tex]F_{2}[/tex] (g)
The concentrations are as following;
[tex]HF[/tex] = 5.82 × [tex]10^{-2}[/tex] M
[tex]H_{2}[/tex] = 8.4 × [tex]10^{-3}[/tex] M
[tex]F_{2}[/tex] = 8.4 × [tex]10^{-3}[/tex] M
So,
[tex]K_{eq}[/tex] = [([tex]H_{2}[/tex] ) × ([tex]F_{2}[/tex])] ÷ [[tex]HF[/tex]]^2
Now,
We can determine the value of [tex]K_{eq}[/tex] by substituting the values in above formula:
[tex]K_{eq}[/tex] = [ (8.4 × [tex]10^{-3}[/tex] M) × (8.4 × [tex]10^{-3}[/tex] M)] ÷ [(5.82 × [tex]10^{-2}[/tex])^2
= 2.08 * [tex]10^{-2}[/tex]
= 2.1 × [tex]10^{-2}[/tex]
∵ [tex]K_{eq}[/tex] = 2.1 × [tex]10^{-2}[/tex]
Thus, option A is the correct answer.
Which is the formula mass of (NH4)2SO4?
96.07 amu
114.12 amu
116.17 amu
132.17 amu
Answer:
132.17amu
Explanation:
(14.01+1.01 multiplied by 4)=18.05×2=36.1
36.1+32.07= 68.17
16.00×4=64
68.17+64=132.17
Answer:
132.17 amu
Explanation:
just took the test. got 100
What was the main aim of Cavendish’s work?
Answer:
The Cavendish experiment, performed in 1797–1798 by English scientist Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory and the first to yield accurate values for the gravitational constant
Explanation:
I think that's correct
use the the dot strict on the right to and the periodic table to determine the element represented.
sodium (Na)
potassium (K)
neon (Ne)
argon (Ar)
Answer:
Pottasium
Explanation:
because it is the nineteenth element
Answer:
The answer is B. Potassium.
Explanation: Potassium has 19 electrons that are organized like the image if you count the electrons on each obital. This answer is correct on edge 2020. Hope this helps!
A gas that was cooled to 200 Kelvin has a volume of 65.8 L. If its initial volume was 132.4 L, what was its initial temperature?
Answer:
Initial temperature, T1 = 99.4 Kelvin
Explanation:
Given the following data;
Initial volume, V1 = 65.8 LitresFinal temperature, T2 = 200 KelvinFinal volume, V2 = 132.4 LitresTo find the initial temperature (T1), we would use Charles' law;
Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Charles' law is given by the formula;
[tex] \frac {V}{T} = K [/tex]
[tex] \frac {V_{1}}{T_{1}} = \frac {V_{2}}{T_{2}} [/tex]
Making T1 as the subject formula, we have;
[tex] T_{1} = \frac {V_{1}T_{2}}{V_{2}} [/tex]
Substituting the values into the formula, we have;
[tex] T_{1} = \frac {65.8 * 200}{132.4} [/tex]
[tex] T_{1} = \frac {13160}{132.4} [/tex]
Initial temperature, T1 = 99.4 Kelvin
Given: CNO2
a) Draw the Lewis structures (Do not forget to show the calculation of the number of available valance electrons)
b) Name the geometry shape
c) Indicate the polarity (polar or non-polar)
Answer:
since there are no lone pairs on the central atom, this would be a trigonal planar molecule. It's polar because the shape of it does not cancel its polarity (you can think of it as not having a balanced electronegativity pull, since the nitrogen is pulling on one side, and the oxygens are pulling on the other. It would be nonpolar if the there were 3 Oxygens).
Sorry this take a little bit long. I was a little confused by the odd valence number
Match each lab incident to the item of PPE that will protect you from it. Each item of PPE will only be used once.
While picking up a buret, an unknown solution left by a previous solution drips onto your hand._______________
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor _______
While checking on a stirring solution, the solution splashes up towards your face. _______
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench, __________
A. Gloves
B. Lab coat
C. Goggles
D. Closed-toe shoes
While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes
While checking on a stirring solution, the solution splashes up towards your face - Goggles
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat
Explanation:
The full form of PPE is 'Personal Protective Equipment'.The PPE items we use in labs are : Lab coat: Protection of clothing and skin from accidental spilling of hot liquid or toxic substances. Gloves: Protection from hands from chemicals, hot objects, sharp tools, or electricityGoggles: Protection of the eye from any chemicals, toxic vapor, chemical debrisFace shield: Protection of the face from any chemicals, toxic vapor, chemical debrisClosed-toe shoes: Protection from feet from chemicals, hot objects, sharp tools, or electricitySo, according to the question. the matches will be:
While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves
While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes
While checking on a stirring solution, the solution splashes up towards your face - Goggles
While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat
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What is the change in enthalpy of the first reaction below, given the enthalpies of the other two reactions?
Here's the reactions:
There was a formatting issue with the specific chemistry symbols, there all correct in the picture below
2C(s) + O2(g) → 2CO(g)
C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol
CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol
There was a formatting issue with the specific chemistry symbols, there all correct in the picture below
Answer:
∆H0 = -222kJ/mol
Explanation:
Using Hess's law, we can find the ΔH of a reaction from the sum of another related reactions as follows:
Using the reactions:
(1) C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol
(2) CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol
Twice (1):
2C(s) + 2O2(g) → 2CO2(g) ∆H0= 2*-394 KJ/mol = -788kJ/mol
The inverse reaction of (2):
-(2) CO2(g) → CO(g) + 1/2 O2(g) ∆H0= 283 KJ/mol
Twice this reaction:
2*-(2) 2CO2(g) → 2CO(s) + O2(g) ∆H0= 2*283 KJ/mol= 566kJ/mol
Now, the sum of 2*(1) - 2*(2) produce:
2C(s) + 2O2(g) + 2CO2(g)→ 2CO2(g) + 2CO(g) + O2(g) ∆H0= -788kJ/mol + 566kJ/mol
Subtracting the molecules that ar in both sides of the reaction:
2C(s) + O2(g) → 2CO(g) ∆H0 = -222kJ/mol
Which condition will probably not increase
the rate of reaction?
a. Adding water to dilute the reaction
mixture
b. Increasing the temperature
c. Adding a catalyst
d. Removing an oxide coating on a
metal
Answer:
i think A.
Explanation:
bc B. makes the molecules hight temp = move faster = more collisions = higher rate, C. it's use is to make reactions rates increase, D. somthung abt more surface area and easier collisions
For the reaction 2A + 4B ----> 2C + 2D, at a particular instant in time, the rate of the reaction is 0.0352 M/s. What is the rate of change of B? Show Work!
A. 0.0088 M/s
B. -0.0088 M/s
C. -0.141 M/s
D. -0.0352 M/s
E. 0.141 M/s
Explanation:
The given chemical equation is:
[tex]2A + 4B -> 2C + 2D[/tex]
The rate of the reaction is 0.0352 M/s.
During the course of the reaction, the rate of reactants decreases, and the rate of products increases.
The rate of disappearance of B is shown below:
[tex]rate=-\frac{1}{4} \frac{d[B]}{dt}[/tex]
So, rate of change of B is :
[tex]rate of change of B =- rate * 4\\=-0.0352 M/s * 4\\=-0.1408M/s\\\\=-0.141M/s[/tex]
Option C.
In the given reaction, rate of change of reactant B is equal to -0.141 M/s.
What is the rate of reaction?Rate of any chemical reaction defines the speed of the completion of that reaction.
In the question given reaction is:
2A + 4B ----> 2C + 2D
Rate of reaction = 0.0352 M/s.
Rate of the reaction with respect to the reactant B is written as:
Rate = [tex]${\rm{ - }}\frac{{\rm{1}}}{{\rm{4}}}\frac{{\left[ {{\rm{dB}}} \right]}}{{{\rm{dT}}}}$[/tex], where negative sign shows the disappearance of reactant B.
Rate of change of B i.e. [tex]$\frac{{{\rm{dB}}}}{{{\rm{dT}}}}$[/tex] = 4 × (-rate)
[tex]$\frac{{{\rm{dB}}}}{{{\rm{dT}}}}$[/tex] = 4 × (-0.0352) = -0.1408 = -0.141 M/s
Hence, -0.141 M/s is the rate of change of B.
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Please hurry this is due tomorrow morning
A student is studying the ways different elements are similar to one another. Diagrams of
atoms from four different elements are shown below.
Which two atoms are of elements in the same group in the periodic table?
F Atom 1 and Atom 2
G Atom 1 and Atom 4
H Atom 2 and Atom 3
J Atom 3 and Atom 4
