The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).
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
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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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
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 type of molecule is shown below?
0
doch
H-CO-CH3
O A. Alcohol
O B. Ester
O C. Aldehyde
i
D. Ketone
Answer:
B. Ester
Explanation:
"Esters have the general formula RCOOR′, where R may be a hydrogen atom, an alkyl group, or an aryl group, and R′ may be an alkyl group or an aryl group but not a hydrogen atom."
The type of molecule is ester.
What is molecule?A molecule is a collection of more than one atom bound together by chemical bonds; based on the circumstances, the phrase will not include ions that meet this requirement.
What is ester?Esters were chemical molecules formed by mixing an oxoacid and a hydroxyl substance like alcohol as well as phenol.
It can be seen that molecule have -COO group which represent ester group. Hence, given molecule have ester group.
Therefore, the correct answer will be option (B).
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Question 6 I need help
The answer is zero also I suggest googling the questions there is a quizlet with the answers
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
Name five metal which are both dilute and memorable? class 10
Putting rock salt on the roads during a snowstorm is an example of: A. Boiling point elevation B. Vapor pressure raising C. Vapor pressure lowering D. Freezing point depression
Answer:
The correct answer is - D. Freezing point depression.
Explanation:
When rock salt is spread over snow-covered icy roads, it generates a liquid layer over it by melting from the surface thereby lowering or depression in the freezing point below the ice.
Therefore, due to this liquid layer comes into the contact with the ice present on the road and causes other ice to melts. This keeps on decreasing the volume of the ice on the road therefore, rock salts spread on the roads during a snowstorm.
What's the velocity of a ball falling with 100 joules of kinetic energy and a mass of 2 kilograms?
А. 3 m/s
B. 5 m/s
C. 7 m/s
D. 8 m/s
E. 10 m/s
Answer:
E
Explanation:
kinetic energy of linear motion
[tex]k.e = \frac{1}{2} m {v}^{2} [/tex]
kinetic energy, K.e= 100joules
mass, m = 2kg
velocity, v =?
substituting the values into the formula :
[tex]100joules = \frac{1}{2} \times 2kg \times {v}^{2} [/tex]
[tex] {v }^{2} = 100[/tex]
[tex]v = \sqrt{100 } [/tex]
[tex]v = 10m { \sec }^{ - 1} [/tex]
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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Values for the molar mass of hydrogen, oxygen, and water molecules are
given in the table below. What mass of water is formed when 2 moles of
hydrogen react with 1 mole of oxygen to form water?
Molecule
Molar mass (g/mol)
H2
2.02
02
32.00
H20
18.01
A.9.00 g
B. 36.02 g
C. 2.00 g
D. 18.01 g
Answer:
36.02g bbbbbbbbbbb hbbnjkkkj
Answer:
36.02g
Explanation:
Hope this helps!
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.
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*
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!
What tricks to use to differentiate between Ionic and Covalent bonds
Answer: first of all an ionic bonds is the electrostatic force of attraction between opposite ions and and covalent bonds is the bond between different elements mostly non metals or the sharing of electrons between elements which are mostly non metals.
Explanation: metals and non metals react to form ionic compounds
and non metals react to form covalent bonds
HOW TO DIFFERENTIATE
ionic solids the particles are charged and the forces between them are strong
covalent solids the particles are not charged and the forces between them are weak
now i would differentiate using their properties
ionic bonds / compounds
have high melting point
have low melting point
They are soluble in water
and they conduct electricity even when melted or dissolved in water
covalent bonds /compounds
they have low melting point
they have low melting point
They are insoluble
they do not conduct electricity
HOPE THIS HELPS!!!
On a heating curve, in which section(s) would you use the equation, Q=mCΔT, to calculate the total heat required?
on all sloped parts of the curve
on a sloped part only if under 0oC
on a sloped part only if over 100oC
only on plateaus or flat parts of the curve
Answer:
69.420 b=99699969
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:
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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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.
Can someone help with this please
Answer:
see explanations
Explanation:
4NH₃(g) + 5O₂(g) => 4NO(g) + 6H₂O(g)
Ci(NH₃) = 3.5mole/4L = 0.875M
Cf(NH₃) = 1.6mole/4L = 0.400M
Rate-1 => Δ[NH₃]/Δt = |(0.400M - 0.875M)/3min| = 0.158M/s
Rate-2 => 6(Δ[NH₃]/Δt) = 4(Δ[H₂O]/Δt) => 6/4(0.158M/s) = 0.237M/s
Rate-3 => 5(Δ[NH₃]/Δt) = 4(Δ[O₂]/Δt) => 5/4(0.158M/s) = 0.237M/s
_________________________________________________________
NOTE: When setting up comparative rate expressions for a given reaction, set the rates expressions as equal then swap coefficient values. Then solve for rate of interest and substitute givens.
example: for NH₃ and H₂O
set rates expressions equal => Δ[NH₃]/Δt = Δ[H₂O]/Δt then swap and insert coefficients from given rxn ...solve for rate of interest ...4NH₃(g) + 5O₂(g) => 4NO(g) + 6H₂O(g)
=> 6(Δ[NH₃]/Δt) = 4(Δ[H₂O]/Δt)
=> Δ[H₂O]/Δt = 6/4(Δ[NH₃]/Δt) = 6/4(0.237M/s) = 0.237M/s
Scientists in a lab are working on a series of experiments that involve colliding two or more atomic nuclei at very high speeds to form a new type of atomic nucleus. What are they working on?
convection
radiation
nuclear fusion
nuclear fission
Answer: Scientists are working on nuclear fusion process. Nuclear fusion is the process in which two atomic nuclei combine to form another nuclei. In the process either energy is absorbed or released due to the difference in the mass of reactants and products.
Explanation:
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
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:
How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas (O2) using the following reaction by completing the t-chart below.
Answer: 6 moles of [tex]KClO_3[/tex] will be decomposed.
Explanation:
We are given:
Moles of oxygen gas produced = 9 moles
The chemical equation for the decomposition of [tex]KClO_3[/tex] follows:
[tex]2KClO_3\rightarrow 2KCl+3O_2[/tex]
By the stoichiometry of the reaction:
If 3 moles of oxygen gas is produced by 2 moles of [tex]KClO_3[/tex]
So, 9 moles of oxygen gas will be produced by = [tex]\frac{2}{3}\times 9=6mol[/tex] of [tex]KClO_3[/tex]
Hence, 6 moles of [tex]KClO_3[/tex] will be decomposed.
40 POINTS! Will Mark Brainliest if correct answer and all work is shown!
In this reaction: Mg (s) + I₂ (s) → MgI₂ (s)
If 2.08 moles of Mg react with 3.56 moles of I₂, and 1.76 moles of MgI₂ form, what is the percent yield?
Explanation:
here's the answer to your question
Answer:
I'm not really sure. Sorry dude.
Explanation:
Sorry.
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
such as water or oxygen,
All of the matter in a what
is the same?
Answer:
A water molecule consists of two atoms of hydrogen linked by covalent bonds to the same atom of oxygen. Atoms of oxygen are electronegative and attract the shared electrons in their covalent bonds.
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 many grams are in 1.50 moles of KMnO4
Answer:
The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles KMnO4, or 158.033949 grams.
Explanation:
I belive that is correct,hope it helps:)
