Answer:
Atoms must have equal numbers of protons and electrons. In our example, an atom of krypton must contain 36 electrons since it contains 36 protons.
Explanation:
Hope this helps and I hope u have an Amazing day!!
what is meant by valency of an element ? give an example
Answer:
valency of an element is a combining power of an element.
for example oxygen has six valance electron but its valency is 2.
hope it helps.
Which statement best explains why an object appears green in sunlight?
The object absorbs most white light and refracts most green light.
The object refracts most white light and absorbs most green light.
More green light is absorbed while more red and blue light is reflected.
More green light is reflected while more red and blue light is absorbed
Answer:
b i think because i think so
Christopher berg land holds the world record for most distance run on a treadmill in day. He ran 247.54 km. How many miles per hour did Chris have to run to accomplish this?
note: Can you please explain how to do this and not just give the answer?
Answer:
6.408924056 miles/hour.
Explanation:
First we have to convert 247.54 km to miles. The conversion factor will be 1 km = 0.621371 miles. To do this I set up my stoichiometry.
247.54km | 0.621371miles = 153.8141773 miles
| 1 km
Now we have 153.8141773 miles per 1 day. The conversion factor will be 1 day = 24 hours.
153.8141773 miles | 1 day 6.408924056 miles/hour.
1 day | 24 hours
(if you need to know what I did with the stoichiometry just ask! I'll be happy to help!)
how long did it take for a car to travel 20 meters with a speed of 10m/s
Answer:
2 second
Explanation:
yes
what is the mass of 1.20 x 10^25 atoms of He
Answer:
79.7 g He
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
1.20 × 10²⁵ atoms He
Step 2: Identify Conversions
Avogadro's Number
Molar Mass of He - 4.00 g/mol
Step 3: Convert
[tex]1.20 \cdot 10^{25} \ atoms \ He(\frac{1 \ mol \ He}{6.022 \cdot 10^{23} \ atoms \ He} )(\frac{4.00 \ g \ He}{1 \ mol \ He} )[/tex] = 79.7077 g He
Step 4: Check
We are given 3 sig figs. Follow sig fig rules and round.
79.7077 g He ≈ 79.7 g He
How do two nonmetal atoms become more stable and form
compounds?
A) sharing valence electrons
B) Nonmetal atoms do not make compounds with
each other
C) fusing nuclei
D) permanently transferring electrons
Check it
Two non-metals become more stable by sharing valence electrons and forming covalent compounds.
What is covalent compound?
Covalent compound is defined as a type of compound which is formed by the mutual sharing of electrons to form electron pairs between the two atoms.These electron pairs are called as bonding pairs or shared pair of electrons.
Due to the sharing of valence electrons , the atoms are able to achieve a stable electronic configuration . Covalent bonding involves many types of interactions like σ bonding,π bonding ,metal-to-metal bonding ,etc.
Sigma bonds are the strongest covalent bonds while the pi bonds are weaker covalent bonds .Covalent bonds are affected by electronegativities of the atoms present in the molecules.Compounds having covalent bonds have lower melting points as compared to those with ionic bonds.
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SF2 and CH4 have similar, but not identical bond angles. Explain this observation and explain why they are slightly different.
Answer:
In CH4 bond angle is 109.5 but it is slightly less than 109.5 in SF2 both compounds have same hybridization SP3 but bond angle of SF2 is less due to presence of two lone pairs
Explanation:
a material will float on the surface of a liquid if the material has a density less than that of the liquid. given that the density of water is approximately g/ml, will a block of material having a volume of and weighing lb float or sink when placed in a reservoir of water?
The density of water is approximately 1.0 g/mL. So, the block will float in water because it is less dense than water.
What is density?Density is a scalar quantity. It is calculated as the mass divided by the volume.
The density of water is approximately 1.0 g/mL
The volume of 1.2 x 10^4 in^3
and weighing 350 lb
D = m / v where D is density, m is mass and v is volume
Converting 1.2 x 10⁴ into 10³
1.2 x 10⁴ in ³ (16.39 mL/ 1 in3) = 196,980 mL
Converting 350 lb into grams
350 lb (454 grams/1 lb) = 158,900 grams
D = m / v = 158,900 grams / 196,980 mL
D = 0.807 g/mL
Thus, due to its lower density than water, the block will float in the water.
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The question is incomplete. Your most probably complete question is given below:
A material will float on the surface of a liquid if the material has a density less than that of the liquid. Given that the density of water is approximately 1.0 g/mL, will a block of material having a volume of 1.2 x 10^4 in^3 and weighing 350 lb float or sink when placed in a reservoir of water?
Which best represents the law of conservation of mass?
: 6 ORE
mass of reactants > mass of products
O mass of reactants < mass of products
mass of reactants = mass of products
O mass of reactants mass of products
-
Answer:
D. mass of reactants → mass of productsExplanation:
The only difference between the options are the sign. The sign between the two is an arrow to represent the change.
(I know this because we're learning about it in class and it's an arrow not an equal, greater, or less than sign)
If you wanted to take a solid nugget of silver and make it flow so that it can be shaped, how could you do it? you could...
Answer:
It should be heated
Explanation:
To change the solid nugget of silver to liquid so that it can be shaped, the solid mass should be heated to the melting point.
This change is a phase change from solid to liquidWhen the melting point of a substance is reached, the fixed lattice structure collapses. This allows for the particles to slide and flow relative to one another.Therefore a phase change from solid to liquid is attained by heating of the solid to melting point.
\identify which reaction is likely to have the greatest positive enthalpy change. p(g) 5cl(g)→pcl5(g) p(g) 3cl(g)→pcl3(g) pcl3(g)→p(g) 3cl(g) pcl5(g)→p(g) 5cl(g)
The greatest positive enthalpy change has PCl₅(g) → P(g) + 5Cl(g)
An enthalpy change is difference between the enthalpy after the chemical reaction has completed.
An enthalpy change of phosphorus(V) chloride (PCl₅) molecule is energy needed for breaking up one molecule of phosphorus(V) chloride into one phosphorus and five chlorine atoms.
In a chemical reaction, chemical bonds are forming and breaking and this cause the transformation of one group of chemical substances to another.
Energy is needed to break chemical bonds in molecules (positive enthalpy change), while during formation of molecule, energy is released (negative enthalpy change)
The stronger are the bonds, more energy is needed and enthalpy change is more positive.
PCl₅ has more bonds to break than PCl₃.
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What happens when a wave hits an object?
the wave is reflected
the wave continues on
the wave is interfered with
the wave stops
Answer:
the wave is reflected. it starts heading towards the other direction
Explanation:
Which substance is considered to be neutral on the pH Scale? *
2 points
battery acid
pure water
bleach
ocean water
Answer:
Pure Water
Explanation:
Battery acid is well and acid
Bleach is a base
Ocean water is impure so it could lean either way
Please help me with this question please.....
Answer:
gain electrons
Explanation:
"atoms gain electrons, they acquire a negative charge "
235
234
2) Uranium is used in nuclear reactors and is a rare element on earth. Uranium has three common
isotopes. If the abundance of U is 0.01%, the abundance of U is 0.71%, and the abundance of
U is 99.28%, what is the average atomic mass of uranium?
238
Answer:
Average atomic mass of uranium = 237.97 amu
Explanation:
Given data:
Abundance of U-234 = 0.01%
Abundance of U-235 = 0.71%
Abundance of U-238 = 99.28%
Average atomic mass of uranium = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass) / 100
Average atomic mass = (234×0.01)+(235×0.71)+(238+99.28) /100
Average atomic mass = 2.34 + 166.85+23628.64 / 100
Average atomic mass = 23797.83 / 100
Average atomic mass = 237.97 amu.
Miguel?? Where are you
Answer:
in the movie ' Coco '.........
60 POINTS! PLEASE ANSWER!
Which are examples of elements? Select all that apply
CO2
C
H2O
Au
PLEASE HELP QUICK Lab - Limiting Reactant and Percent Yield
Data (Trial 1) (5 Points)
Observations during Reaction:
3CuCl2(aq) + 2Al(s) → 3Cu(s) +2AlCl3(aq)
Measured Mass (g)
N/A
N/A
Molar Mass ( )
134.45
26.98
N/A
N/A
Actual Moles (mol)
N/A
N/A
Analysis: The limiting reactant is _ because . . .
Data (Trial 2) (5 Points)
Observations during Reaction:
3CuCl2(aq) + 2Al(s) → 3Cu(s) +2AlCl3(aq)
Measured Mass (g)
Filter paper alone Filter paper + Cu
Cu alone
N/A
Molar Mass ( )
134.45
26.98
63.55
N/A
Actual Moles (mol)
N/A
Analysis: The limiting reactant is _ because . . .
Theoretical yield of copper based on the limiting reactant; (insert the answer from above)
_ _: _ _ moles = _ g
Percent yield: _ _%
Limiting Reactant and Percent Yield - Lab Report
Purpose (5 Points)
Hypothesis (5 Points)
Analysis
(5 Points) If you put a piece of zinc into a solution of copper (I) sulfate and allow the single replacement reaction to go to completion, how will you know which of the reactants is the limiting reactant? Write the balanced equation, including the states of matter of the reactants and products, to help support your answer.
CuSO4(___) + Zn (__) → Cu(__) + ZnSO4 (___)
Is it balanced? __________ If not, fix it.
(5 Points) What is the difference in actual yield and theoretical yield?
Solid Silicon can be reacted with Nitrogen gas at a high temperature to form silicon nitride (Si3N4).
1.20 moles of Silicon are added to 1.00 moles of Nitrogen gas.
(5 Points) Balance the equation and indicate the phases.
Si (___) + N2 (___) → Si3N4 (___)
(5 Points) What is the limiting reactant? You must show your work.
(5 Points) How many moles of silicon nitride will be made? You must show your work.
(5 Points) What is the benefit of having a limiting reactant in a reaction?
(5 Points) In a manufacturing process why would you prefer not to have a limiting reactant?
(5 Points) Can you tell from the masses of the reactants which one of the reactants will be the limiting reactant? Defend your answer (use an equation within your defense).
4.95 g of ethylene (C2H4) are combusted with 3.25 g of oxygen.
(5 Points) Balance the equation. (ethylene plus oxygen yields carbon dioxide and water)
C2H4 + O2 → CO2 + H2O
(5 Points) What is the limiting reactant? You must show your work.
(5 Points) If the actual yield of Carbon dioxide is 2.50 g, what is the percent yield for the reaction? You must show your work.
Silver nitrate reacts with iron (III) chloride to give silver chloride and ferric nitrate. In a particular experiment, it was planned to mix a solution containing 25.0 g of silver nitrate with another solution containing 45.0 grams of iron (III) chloride.
(5 Points) Balance the equation.
AgNO3 + FeCl3 → AgCl + Fe(NO3)3
(5 Points) What is the limiting reactant? You must show your work.
(5 Points) What is the theoretical yield of grams of AgCl that could be obtained? You must show your work.
(10 Points) When 56.6 g of solid calcium and 30.5 g of nitrogen gas undergo a reaction that has a 93.0% yield, what mass of calcium nitride forms? Make sure you balance the equation to help solve the question and show all of your work.
Ca(s) + N2 (g) → Ca3N2 (s)
Answer:
im stuck on it too unfortunatley
Explanation:
One difference between molecular formula and molecular weight.
Answer: The formula mass (formula weight) of a molecule is the sum of the atomic weights of the atoms in its empirical formula. The molecular mass (molecular weight) of a molecule is its average mass as calculated by adding together the atomic weights of the atoms in the molecular formula.
Hope this helps.... Stay safe and have a great weekend!!!!! :D
Willie has fewer than normal bacteria in his gut microbiome. How will this affect his health?
Answer:
Indegestion I believe as there isn't as much bacteria to break down his food.
Explanation:
Tbh, dont complain if you don't like a food, because when you chew it, its gonna turn into some white mush anyways, and when it comes out, its brown.
Dont blame me, blame your tooth.
Using the table below, identify the unknown material that has a mass of 15,06 g and a
volume of 0.78 ml
Substance Density (g/cm) Substance Density (g/cm")
Ice (00 0.917 Human fat 0.94
Water (4.0°C) 1.0000 Cork 0.22-0.26
Gold
19.31
Table sugar 159
Helium (250) 0.000 164 Balsa wood 0.12
Air (250) 0.001 185 Earth 5.54
Ole
Water
Gold
Hellum
O Air
lo
The unknown material : gold
Further explanationDensity is a quantity derived from the mass and volume
Density is the ratio of mass per unit volume
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
mass of unknown the material : 15.06 g
volume = 0.78 ml
The density :
[tex]\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{15.06}{0.78}=19.31~g/ml[/tex]
materials that match the density: gold
WILL GIVE BRAINLIEST ANSWER!!!
I have 345 mL of a 1.50 M NaCl solution. If I boil the water until the volume of the solution is 250. mL, what will the molarity of the solution be?
Answer: 2.07 M
Explanation:
(1.5m) (345ml)
---------------------
250 ML = 2.07M
15. What is the wavelength of a 1.32 x 10^-6 eV wave?
The wavelength of a 1.32 x 10-⁶ eV wave is 0.939m or 9.39 × 10⁸nm.
How to calculate wavelength?The wavelength of a wave can be calculated using the following formula:
wavelength = speed ÷ frequency
However, the frequency of the wave needs to be calculated first using the formula as follows:
E = hf
Where;
E = energy of the waveh = Planck's constant (6.626 × 10-³⁴J/s)f = frequency1 electronvolt = 1.602 × 10-19 joule
Hence, 1.32 × 10-⁶ eV is equivalent to 2.11487 × 10-²⁵J.
2.11487 × 10-²⁵J = 6.626 × 10-³⁴ × f
f = 2.11487 × 10-²⁵ ÷ 6.626 × 10-³⁴
f = 3.2 × 10⁸Hz
Wavelength = 3 × 10⁸ ÷ 3.2 × 10⁸
Wavelength = 0.9375 × 10⁰
Wavelength = 0.94m
Therefore, the wavelength of a 1.32 x 10-⁶ eV wave is 0.939m.
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What are the most common metric units used in science?
Answer its a
Explanation:
in 2 hours a bicyclist traveled 75 kilometers. What was the bicyclist's average speed?
Answer:
37.5 miles per hour....
To verify the law of Conservation of mass in a chemical reaction.
Write the formulae of the following-
a) Magnesium hydroxide
b) Hydrogen sulphide
c) Calcium oxide
d) Barium chloride
e) Sodium carbonate
f) Ammonium sulphate
g) Aluminium oxide
h) Magnesium bicarbonate
i) Aluminium phosphate
j) Silver nitrate
Answer:
To verify the law of Conservation of mass in a chemical reaction.
Write the formulae of the following-
a) Magnesium hydroxide
b) Hydrogen sulphide
c) Calcium oxide
d) Barium chloride
e) Sodium carbonate
f) Ammonium sulphate
g) Aluminium oxide
h) Magnesium bicarbonate
i) Aluminium phosphate
j) Silver nitrate
A cup of coffee(140g) cools from 75 degrees Celsius down to comfortable room temperature 20 degrees Celsius. How much energy does it release to the surroundings.
Energy releases to the surroundings = -32.2 kJ
Further explanationHeat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
mass of coffee(m) = 140 g
∆T = temperature difference :
final temperature - initial temperature = 20-75=-55°C
specific heat coffee= specific heat water = 4.18 J/g° C
The heat releases :
[tex]\tt Q=140\times 4.18\times -55\\\\Q=-32186~J\approx -32.2~kJ[/tex]
What is the difference between atomic elements and molecular elements?
When Philip analyzed unknown substance x, he found that it contained only one kind of atom what is substance x