Answer:
Valence electrons are the electrons in the outermost shell, or energy level, of an atom. For example, oxygen has six valence electrons, two in the 2s subshell and four in the 2p subshell.
Answer question number 3
Answer:
A
Explanation:
A mixture is formed when two or more substances are physically mixed together. A compound is formed when two or more substances are chemically combined through a chemical reaction.
1. Using a triple beam balance and a graduated cylinder, a student collected data on a sample of an
element:
Mass of sample - 67.9 g
Volume of water - 52.0 ml
Volume of water and sample - 28.0 ml
a) Calculate the density of the sample. Show all work and use significant figures and units.
Answer:
d = 2.8 g/mL
Explanation:
Given data:
Mass of sample = 67.9 g
Volume of water = 28.0 mL
Volume of water + sample = 52.0 mL
Density of sample = ?
Solution;
Density is equal to the mass of substance over volume of substance.
Formula:
d = m/v
d = density
m = mass
v= volume
Now we will calculate the volume of sample.
Volume of sample = (volume of water+ sample) - volume of water
Volume of sample = 52.0 mL - 28.0 mL
Volume of sample = 24.0 mL
Now we will calculate the density.
d =67.9 g /24.0 mL
d = 2.8 g/mL
Match the terms below to the correct definitions
3. Atom
1. The mass on the periodic table.
b. Electrons
2. Region surrounding the nucleus where electrons are found.
C. Protons
3. Positively charged center of an atom.
d. Neutrons
4. Particles that differ in number between isotopes.
e. Electron
cloud
5. Vertical column in the periodic table.
1. Nucleus
6. Positively charged particles in an atom.
R. Quark
7. Negatively charged particles in the outermost energy levels of the electron cloud.
8. Table that organizes the elements by properties.
9. Atoms of the same element that have different masses.
h. Atomic
number
1. Mass number
10. Smallest known particle that makes up protons and neutrons.
j. Average
atomic mass
11. All elements in the same one of these has the same number of energy levels in
their electron cloud.
k. Isotopes
12. The smallest form of matter that still retains the properties of an element.
1. Valence
electrons
13. Negatively charged particles in an atom.
m. Group
14. The sum of protons and neutrons in an atom.
n. Period
15. Represents the identity of an element.
o. Periodic
Table
Answer:
Explanation:
1=i
4=d
5=m
6=c
8=o
9=j
10=a
13=b
14=h
15=l
Theses are the ones i knew
what is 1.23 x 10^-3 in standard notation
Answer:
=0.00123
Explanation:
Look at the attachments below
Hope this helps (:
Answer:
0.00123
Explanation:
Standard notation is the normal way of writing numbers. Examples include 1, 2, and 10. The number 1.23 x 10^-3 is written in scientific notation. The decimal goes after the first nonzero integer and it is multiplied by a power of 10. The power or exponent attached to the 10 tells you how many places over you need to move the decimal to get back into scientific notation. Examples include 1.00 x 10^2 (representing 100 in standard form because you would move the decimal two places to the right.), 2.0 x 10^1 (representing 20 in standard form because you would move the decimal one place to the right), and 3.0 x 10^-4 (representing 0.0003 in standard form because you would move the decimal four places to the left since it is a negative exponent).
The negative (-3) exponent in 1.23 x 10^-3 indicated to move the decimal three places to the left. If it was positive, you would move it three places to the right.
In 1.23 x 10^-3 move the decimal to the left 1 place to get:
0.123
two places to get:
0.0123
and a third place to get:
0.00123
The final answer is 0.00123
Which of the following is false regarding supersonic speed?
Question 10 options:
When an object reaches supersonic speed a sonic boom will occur.
When an object reaches supersonic speed it is moving faster than the speed of light.
When an object has reaches supersonic speed it breaks the sound barrier.
When an object supersonic speed it is moving faster than 343 meters/second.
Answer:
the answer is C
Explanation:
i know this one, and may YOU PLEASE MARK BRAINLIEST I ONLY NEED ONE MORE CROWN TO MOVE TO THE NEXT RANK
6. A sheet of metal is 2 cm wide, 10 cm tall, and 15 cm long. It was 4 grams. What is the
density?
Answer:
0.013g/cm^3
Explanation:
density= mass÷volume
Answer:
0.01(3) g/cm3 (cm3 means centimeter cubed, (3) means the 3 goes on forever)
Explanation:
The volume of the sheet is 300 cm3, and dividing 4 grams by 300 cm3 gets you 0.01(3) g/cm3. Hope it helps!
What accounts for the attractions in a chemical bond?
Answer:
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds.
Explanation:
How many neutrons make up one of these potassium atoms?
Answer:
20
Explanation:
Refer to your periodic table:
Which of the following has the smallest atomic radius?
Bromine
Astatine
Iodine
Fluorine
iondine
Explanation:
bromine has 185pm, astatine haa 200, iondine has 140 and lastly fluorine has 147. so iondine has the smallest atomic radius
Plowing is an example of what Energy?
a. Kinetic Energy
b. Potencial Energy
Answer:
mechanical or kinetic eg hammer and nails
cy sprints 100 meters in 13 seconds going south. what is his average velocity?
Answer:
Explanation:
This should be in physics.
d = 100 meters south
t = 13 seconds
v = d/t
v = 100 / 13
v = 7.69 m/s going south.
The point is that you have to specify the direction.
How many atoms are present in 7.50 mol of chlorine atoms? _
Answer:
4.52 x 10²⁴ atoms Cl
Explanation:
A mole is a name that means a certain number like a dozen means 12. 1 mole of chlorine atoms is 6.022 x 10²³ chlorine atoms. The unit conversion is 6.022 x 10²³/mol.
[tex]7.50molCl*\frac{6.022 x 10^{23} atomsCl}{1molCl} = 4.5165*10^{24} atomsCl[/tex]
Round to 4.52 x 10²⁴ atoms Cl for the correct number significant figures.
what makes a substance a molecule? it’s 7th grade science
Answer:
Molecular substances are made when two or more atoms join together by covalent bonds.
Explanation:
I hope this helps. I took the same class.
what unit of measure would i use to measure the width of my fingernail A millimeters
B centimeters C meters D kilometers
E grams
What is the correct name for the compound P406?
A. Phosphoric acid
B. Tetraphosphorus hexoxide
C. Phosphorus (IV) oxide
D. Phosphorus oxide
Answer:
Phosphorus trioxide
Explanation:
Answer:
Tetraphosphorus hexoxide
Explanation:
Give brainliest please
An element, X, has 2 isotopes, X-32 with an abundance of 31.5% and X-35 with an abundance
of 68.5%. What is the average atomic mass of element X?
Answer:
amu = 34.055 or 34.1
Explanation:
to calculate the average mass, first convert the percentages into decimals. Then, calculate the mass numbers. To get this number, multiply the decimal by the mass number for each isotope and, then add them together.
( 0.315 x 32 ) + (0.685 x 35 ) = 34.055
Based on the article "Will the real atomic model please stand up?," describe what Dalton's theory states about a molecule of water. Dalton's theory about compounds tells us that all water molecules have different kinds of atoms, two hydrogen atoms for every one oxygen atom.
Answer:
Follows are the solution to this question:
Explanation:
The characterization with water molecules would be that light waves are made up of 2 different types of atoms (2 hydrogen and 1 oxygen atoms), as per the Dalton theory. There are many multiple times as many atoms of hydrogen as oxygen atoms in each water molecules. For every two hydrogen atoms, all water molecules have one oxygen atom.
Answer:
Sample Response: Dalton’s theory about compounds tells us that all water molecules have different kinds of atoms, two hydrogen atoms for every one oxygen atom.
Explanation:
compound name of SO2
Why MgO will form after Mg reacting with CuO? (mcq)
Mg forms positive ions and O forms negative ions
Mg is more reactive than Cu
CuO have loose bonding
Answer:
Mg is more reactive than Cu
Explanation:
In the reaction between Mg and CuO to form MgO, MgO will form because Mg is more reactive than Cu.
This kind of reaction is called a single replacement or single displacement reaction.
The replacement of a metallic ion in solution by a metal atom higher in the activity series than the metal in solution falls into this category of reactions. The element Mg is higher than Cu in the activity series. The higher an element is in the activity series, the more reactive they are. Since Mg is more reactive, it will displace the Cu from CuO.how many atoms can you fit on the head of a pin
Answer:
According to google, "About five million million hydrogen atoms could fit. Some factors would affect that number like the area of the head and the size of atoms (as well as attractions between atoms). Some atoms are larger than others." Is this accurate? I'm not sure. Good luck! :)
Which further observation led Mendeleev to create the periodic table
Answer:
Mendeleev realized that the physical and chemical properties of elements were related to their atomic mass in a 'periodic' way, and arranged them so that groups of elements with similar properties fell into vertical columns in his table.
Explanation:
What is the relationship between the latitude and hours of daylight
Answer:
The tilt of the Earth's axis also defines the length of daylight.Daylight hours are shortest in each hemisphere winter. Between summer and winter
solistice the number of daylight hours decreases and the rate of decrease is larger the higher the latitude.The fewer sunlight hours the colder nights.
N2+H2》NH3
is it balanced or unbalanced
why is lithium used in the body?
Answer:
11
Explanation:
what happens to the molecules as water freezes PLS HELP THIS IS DO TODAY
During freezing, water molecules lose energy and do not vibrate or move around as vigorously. This allows more stable hydrogen-bonds to form between water molecules, as there is less energy to break the bonds. ... Thus water expands as it freezes, and ice floats atop water.
When water molecule freezes, the water molecules have slowed down enough that their attractions fixed them into fixed positions.
What do you mean by freezing ?The term freezing is defined as a phase transition where a liquid converted into a solid when its temperature is lowered below its freezing point.
The freezing point is the temperature at which a liquid turns solid. In the freezer, for example, water-filled ice cube trays.
Water molecules freeze in a hexagonal pattern, with molecules further apart than when the water was liquid. It is worth noting that the molecules in ice would be vibrating.
Thus, When water freezes, the water molecules slow down to the point where their attractions arrange them into fixed positions.
To learn more about the freezing, follow the link;
https://brainly.com/question/26230908
#SPJ2
Write the word equations for the following balanced chemical equations.
a. Zn + 2HCl → ZnCl2 + H2
b. 2503 2502 + O2
Answer:
21
Explanation:9+10
A dull metal object has a density of 8.8 G/ML and a volume of 20 ML calculate the mass
Answer:
Mass = 0.000176 gram
Steps:
m = V × ρ
= 20 milliliter × 8.8 gram/cubic meter
= 2.0E-5 cubic meter × 8.8 gram/cubic meter
= 0.000176 gram
Explanation:
The density of air at STP is 1.285 g/L. Which of the following cannot be used to fill a balloon that will float in air at STP?
NO can't be used to fill a balloon
Further explanationConditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.
Answer options that need to be added :
a. Ne
b. NO
c. NH₃
d. CH₄
e. HF
will float in air ⇒ element or compound to fill the balloon, its density must be less than < 1.285 g/L
We can use the ideal gas formula ta find density :
[tex]\tt \rho=\dfrac{P.MW}{RT}[/tex]
Because at STP, then the constant value is
[tex]\tt \rho=\dfrac{1~atm\times MW}{0.08205\times 273.15~K}\\\\\rho=0.0446\times MW[/tex]
So that the density is determined from the MW(molecular weight) of each element or compound
a. NeAr = 20.1797 g/mol
[tex]\tt \rho=0.0446\times 20.1797=0.9~g/L[/tex]
b. NOMW=30.006 g/mol
[tex]\tt \rho=0.0446\times 30.006=\boxed{\bold{1.338~g/L}}[/tex]
c. NH₃MW=17.0306 g/mol
[tex]\tt \rho=0.0446\times 17.0306=0.760~g/L[/tex]
d. CH₄MW=16.04 g/mol
[tex]\tt \rho=0.0446\times 16.04=0.715~g/L[/tex]
e. HFMW=20.01 g/mol
[tex]\tt \rho=0.0446\times 20.01=0.892~g/L[/tex]
Please help!
We are doing a lab and I have trouble doing the data analysis. Using my data collection, Can you guys help me using the MC delta T equation?
4.94 x c . (Tm-23.6)=C.(23-6-21.9)+123.13 x c. (23.6-21.9)
Further explanationThe law of conservation of energy can be applied to heat changes, ie the heat received/absorbed is the same as the heat released
Q in = Q out
Heat can be calculated using the formula:
Q = mc∆T
A calorimeter is a device used to measure the specific heat of material
A metal is put into a calorimeter that contains water and there will be heat transfer:
[tex]\tt \displaystyle m_mc_m (T_m-T)=m_wc_w(T-Tw)[/tex]
m = metal
w = water
T = the final temperature of the mixture
mass of metal =(Nickel) = 4.94 g
mass of calorimeter = 12.5 g
mass of water = 123.13 g (135.63 - 12.5)
The equation
Q released (metal) = Q absorbed(calorimeter+water)
Qmetal = 4.94 x c . (Tm-23.60)Q calorimeter = C.(23-6-21.9) --> C = heat capacity of calorimeterQ water = 123.13 x c. (23.6-21.9)The equation :
4.94 x c . (Tm-23.6)=C.(23-6-21.9)+123.13 x c. (23.6-21.9)
Where exactly is an orbital? I understand they are a volume where we expect to find electrons 90% of the time but I don't understand where their shapes are and fit on an atom, and the different forms of orbitals confuse me a little. Can someone explain me where they are with the help of an image? Pardon me if my question isn't very clear
Answer:
95% of the time (or any other percentage you choose), the electron will be found within a fairly easily defined region of space quite close to the nucleus. Such a region of space is called an orbital. You can think of an orbital as being the region of space in which the electron lives