Select the correct answer.
Which of the following might cause chemical contamination when used near food?
A.
furniture polish
B.
steel can
Ос.
glass container
OD. plastic bag
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if an atom has 15 protons and a mass of 31 how many neutrons will it have
Answer:
16 neutrons
Explanation:
now that protons are equal to electrons, there are 15 electrons. The mass is equal to 31.0, which is the ≡ of protons and ≡ neutrons added together. To find the number of neutrons, subtract the atomic # from the total mass #. 31-15=16 this would be equal to 16 now that the atomic has 31 and the mass is 15 subtract them ... you would get 16 neutrons inside the nucleus.
hope this helped ((((: if it did then please mark brainliest and have a wonderful day d:
Answer:
16
Explanation:
To find the neutrons, it's always mass-atomic number. Since the atomic number for an atom is always the protons, it's really mass-protons.
31-15=16
what is Brownian motion
Answer: the erratic random movement of microscopic particles in a fluid, as a result of continuous bombardment from molecules of the surrounding medium. Brownian motion, or pedesis, is the random motion of particles suspended in a medium. This pattern of motion typically consists of random fluctuations in a particle's position inside a fluid sub-domain, followed by a relocation to another sub-domain. Brownian motion, also called Brownian movement, any of various physical phenomena in which some quantity is constantly undergoing small, random fluctuations. It was named for the Scottish botanist Robert Brown, the first to study such fluctuations (1827).
Hope this helps...... Stay safe and have a Merry Christmas!!!!!!!!! :D
Explanation:
Answer:
to and fro motion is called brownian motion
How much water would need to be added to 1092 mL of a 54.7 M NaCl solution to make a 0.25 M solution?
Answer:
237.8L of water would need to be added.
Explanation:
The first thing to do is to identify that the equation to be used is M1V1=M2V2. (This equation works because it turns everything into moles which can then be compared).
Then figure out what information you have and what is being found. In this case:
M1 = 54.7 M
V1 = 1092 mL = 1.092 L
M2 = 0.25 M
V2 = unknown
Then solve the equation for whatever you are trying to find.
M1V1=M2V2
V2=M1V1/M2
Now you need to plug everything in.
V2=(54.7M*1.091L)/0.25M
V2=238.93L
That means that the solution needs a volume of 238.7L to gain a molarity of 0.25M but the starting solution already had a volume of 1.092 L meaning that to find the amount of solvent that needs to be added you just subtract the starting volume by the volume that the solution needs to be.
238.93L - 1.091L = 237.8L
Therefore the answer is that 237.8L needs to be added to a 1.092L 54.7M NaCl solution to make the concentration 0.25M.
I hope this helps. Let me know if anything is unclear.
what substance has a mass of 9.5 grams and a volume of 2.1 cm^3?
SUBSTANCE.
Explanation:
Given parameters:
Mass = 9.5g
Volume = 2.1cm³
Unknown:
What kind of substance is this = ?
Solution:
To determine the kind of substance given, we need to find its density from the given parameters.
The density of a substance can tell us about such body.
Density is an intensive property and it is the mass per unit volume.
Density = [tex]\frac{mass}{volume}[/tex]
Now insert the parameters and solve;
Density = [tex]\frac{9.5}{2.1}[/tex] = 4.52g/cm³
The substance will most likely be a solid.
Which of the following bonds would be the most polar without being considered ionic? a. Mg-o b. C-O C. N-O d. Si-O
Answer:
the answer is c hope this helps
Explanation:
N-O is the most polar without being considered ionic. Hence, option C is correct.
What is an ionic bond?An ionic bond is formed by the complete transfer of some electrons from one atom to another.
Bonds between carbon and other elements such as oxygen or nitrogen are polar. The polarity of a bond depends upon the electronegativities of the bonded atoms.
Hence, option C is correct.
Learn more about ionic bonds here:
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Is it balanced or unbalanced
Describe the process of dimensional analysis and explain why it is so useful in chemical problem solving.
Answer:
Dimensional Analysis (also called Factor-Label Method or the Unit Factor Method) is a problem-solving method that uses the fact that any number or expression can be multiplied by one without changing its value. It is a useful technique.
how many moles is 8.72x10^24 atoms? can you solve the equation too?
Answer:
14.49 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{8.72 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 14.48504...[/tex]
We have the final answer as
14.49 molesHope this helps you
Write a report on waves
Answer:
The epic emotional journey of a suburban African American family as they navigate love, forgiveness and coming together in the wake of a tragic loss.
Explanation:
hope thsi helps if so please brainliest
Merry Christmas
What do the rows in the Periodic Table tell us?
Answer:
The rows tell you how many shells there are of the atom.
What is electrons configuration for arsenic ?
Answer:
[Ar] 3d¹⁰ 4s² 4p³
Explanation:
so...... ur welcome
Which state of matter has neutral particles that bounce off one another as they collide? A: Gas B: Liquid C: Plasma D: Solid
Answer:
Gas
Explanation:
Help plz:))) I’ll mark u brainliest ASAP 10 points
Answer: I believe it’s the second one
(F)
Explanation:
Which of the following has a tetrahedral molecular geometry?
NH3
CCl4
H2O
CO32-
Answer:
CCl₄
Explanation:
The molecule with a tetrahedral molecular geometry is CCl₄.
We know this according the valence shell electron pair repulsion theory.
To have a tetrahedral shape, a molecule must be made up of 4 bond pairs and no lone pairs.
This is clearly exhibited in the compound given;
The central atom has 4 valence electrons which is completed bonded by 4 chlorine atom.
There is no lone pair but we have 4 bond pairs and a tetrahedral shape is formed.
11.
A sample of TNT, C-H5N306, has 7.30 1021 nitrogen atoms. Determine the numbers of
hydrogen atoms in this sample of TNT.
021
Answer:
1.22 × 10^22 H atoms
Explanation:
From this question, TNT has the chemical formula: C-H5N306. The number of nitrogen atoms in the TNT substance is said to be 7.30 × 10^21 atoms.
The number of hydrogen atoms in the same TNT substance can be got using mole ratio. Based on the chemical formula, the mole ratio of hydrogen to nitrogen is 5:3 i.e. H5N3.
This means that;
Number of atoms of hydrogen = 5/3 of the number of atoms of nitrogen.
Hence, number of H atoms = 5/3 × 7.30 × 10^21
number of H atoms = (7.30 × 5/3) × 10^21
number of H atoms = (36.5/3) × 10^21
number of H atoms = 12.1666 × 10^21
number of H atoms = 1.2166 × 10^22 atoms.
Approximately, number of H atoms in TNT is 1.22 × 10^22 atoms.
A chemical reaction in a lab experiment actually produces 1.23mol of BeBr2. The theoretical yield is 220g. To two decimal places, what is the percentage yield
Answer:
Percent yield = 94.62%
Explanation:
Given data:
Actual yield of BeBr₂ = 1.23 mol
Theoretical yield of BeBr₂ = 220 g
Percent yield = ?
Solution:
Theoretical yield in moles:
Number of moles = mass/molar mass
Number of moles = 220 g/168.82 g/mol
Number of moles = 1.30 mol
Percent yield:
Percent tiled = actual yield / theoretical yield × 100
by putting values,
Percent yield = 1.23 mol / 1.30 mol × 100
Percent yield = 0.9462 × 100
Percent yield = 94.62%
Which salt solution is most likely to be colored?
Answer:
K2CrO4 (aq)
Explanation:
previous nect
Which type of rock forms when an existing rock changes under extreme pressure and intense heat?
A
igneous
B
sedimentary
C
metamorphic
Answer:
c
Explanation:
metamorphic rocks
Answer:
C. Metamorphic
Explanation:
Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2
What mass of carbon monoxide is needed to react with 1.80g Fe2O3
Mass of carbon monoxide : 0.95 g
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂
MW Fe₂O₃ : 159,69 g/mol
mol Fe₂O₃ :
[tex]\tt \dfrac{1.8}{159.69}=0.0113[/tex]
mol ratio Fe₂O₃ : CO = 1 : 3, so mol CO :
[tex]\tt 3\times 0.0113=0.0339[/tex]
mass CO (MW = 28,01 g/mol) :
[tex]\tt m=mol\times MW\\\\m=0.0339\times 28.01\\\\m=0.950~g[/tex]
Example of market structures of monopoly
Answer: A monopoly is the absence of competition in the market.
Explanation:
In such circumstances, the market creates a monopoly of one producer who takes huge capital and dictates prices. An example of a monopoly on the market is the existence of only one company that makes up the entire economic branch. In such circumstances, the monopolist can increase the product's price without losing the entire sale, i.e., operating successfully. In that situation, the monopolist remains the only one on the market, and the competition has no access to the market.
A 2.52 L container of oxygen gas at 28.6 °C is heated to 45.9 °C. Assuming that the volume of the container can vary, what is the new volume of the gas?
Answer:
4.04433566 L (433566 repeating)
Explanation:
2.52 is divided by 28.6 is 0.0881118 (881118 repeating). multiply 0.0881118 (881118 repeating) by 45.9 to get 4.04433566 L (433566 repeating).
hydrocarbon structures methopane
The cost of table of sugar C12 H22 O11 is RS 24 per kg calculate it cost mole
Answer:
One mole of sugar is a considered as atomic mass. The atomic mass of sugar is 342 g. Rate of 1 kg of sugar is 40 Rs. Thus, the rate of 342 gram of sugar= 40x342/1000 = 13.68 Rupees
Explanation:
A complex absorbs photons with an energy of 4.10×10^−19 J. What is the wavelength of these photons? If this is the only place in the visible spectrum where the complex absorbs light, what color would you expect the complex to be?
Answer:
483 nm corresponds to blue light hence the complex will appear orange.
Explanation:
Using the formula;
E= hc/λ
Where;
E = energy of the photon
h = Plank's constant (6.6*10^-34Js)
c = Speed of light (3*10^8 ms-1)
λ = wavelength
λ = hc/E
λ = 6.6*10^-34 * 3*10^8/4.10×10^−19
λ = 4.83 * 10^-7 or 483 nm
483 nm corresponds to blue light
Using the colour wheel approach, if a complex absorbs blue light, then it will appear orange.
17 Which changes decrease the rate of reaction between magnesium and air?
1.heating the magnesium to a higher temperature
2.using a higher proportion of oxygen in the air
3.using magnesium ribbon instead of powdered magnesium
A 1, 2 and 3
B 1 only
C 2 only
D 3 only
Using magnesium ribbon instead of powdered magnesium decrease the rate of reaction between magnesium and air.
What is rate of reaction?Rate of reaction tells about the duration of the completion of the reaction.
Rate of any reaction is directly proportional to the concentration and surface area of the reactant, temperature, catalyst, no. of collision, activation energy, etc.
So, if we magnesium in the ribbon instead of powdered magnesium the surface area of the reactant side decreases which results in the decrease of the rate of reaction.
Hence, option (D) is correct i.e. rate of reaction decreases on using magnesium ribbon instead of powdered magnesium.
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3 elements that have similar properties
Answer:The elements in the first column of the Periodic Table (other than hydrogen) are known as Group 1A metals, or alkali metals. When you compare the chemical properties of these elements (lithium, sodium, potassium, rubidium, cesium, and francium), what you'll notice is that they are all remarkably similar.
Explanation:
Lithium, sodium, and potassium are the three elements from group number 1 of the periodic table that has similar chemical and physical properties, these group 1 metals are also known as alkali metals.
What is the atomic number?The total number of protons present in an atom is known as the atomic number of that atom. The atomic number has no correlation either with the number of neutrons or the number of electrons present inside an atom.
Group 1 metals, often known as alkali metals, are a trio of elements from the periodic table that have similar chemical and physical characteristics. They are lithium, sodium, and potassium.
Thus, Lithium, sodium, and potassium are the three elements from group number 1 of the periodic table that has similar chemical and physical properties.
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A system gains 687 kJ of heat, resulting in a change in internal energy of the system equal to 156 kJ. How much work is done?
1. Work was done by the system.2. Work was done on the system.
Answer:
w = -531 kJ
1. Work was done by the system.
Explanation:
Step 1: Given data
Heat gained by the system (q): 687 kJ (By convention, when the system absorbs heat, q > 0).Change in the internal energy of the system (ΔU°): 156 kJStep 2: Calculate the work done (w)
We will use the following expression.
ΔU° = q + w
w = ΔU° - q
w = 156 kJ - 687 kJ
w = -531 kJ
By convention, when w < 0, work is done by the system on the surroundings.
NEED HELP ASAP!!
(04.04 LC)
Which statement is true about the products of cellular respiration?
They contain oxygen.
They contain glucose.
They become the products of photosynthesis.
They become the reactants of photosynthesis.
Answer:
They contain oxygen
hope it helps
100
80
100 mL
water vapor
Which statement describes what will happen if a student
pushes the plunger
to compress the water vapor?
A. The total number of water particles will increase.
B. The amount of energy in the water particles will decrease.
C. The amount of empty space between the water particles will
decrease.
O D. The total volume of the water particles will increase.
I will mark brainliest
Answer: c (the amount of empty space between the water particles will decrease)
Explanation: i got it right:)