Answer:
Explanation:
# moles that exist in 1.9 X 10 23 =
= # of atoms/# of Avogadro 's num
= 1.9 X 10 23 / 6.02x10 23
= 0.266 mole of Pb
now we calculate the mass
mass of lead = # mol x m.wt
= 0.266 X 106.4
= 28.30 gram
A pure copper penny contains approximately 2.9×1022 copper atoms. Use the following definitions to determine how many ______ of copper atoms are in a penny. 1doz=12 1gross=144 1ream=500 1mol=6.022×1023 Part A dozens Express your answer in dozens to two significant figures.
Complete question is;
A pure copper penny contains approximately 2.9 × 10^(22) copper atoms.
1 doz = 12
1 gross = 144
1 ream = 500
1 mol = 6.022 × 10^(23)
Use these definitions to determine the following:
A) How many dozens of copper atoms are in a penny.
B) How many gross of copper atoms are in a penny
C) How many reams of copper atoms are in a penny.
D) how many moles of copper atoms are in a penny?
All answers can be rounded to two significant figures
Answer:
A) 2.4 × 10^(21) dozens
B) 2.01 × 10^(20) gross
C) 5.8 × 10^(19) reams
D) 0.048 mol
Explanation:
A) A dozen contains 12.
Therefore, 2.9 × 10^(22) copper atoms will contain;
(2.9 × 10^(22))/12 dozens = 2.42 × 10^(21).
In 2 significant figures, we have;
2.4 × 10^(21) dozens
B) 1 gross = 144
Therefore, 2.9 × 10^(22) copper atoms will contain;
(2.9 × 10^(22))/144 gross ≈ 2.01 × 10^(20) gross
C) 1 ream = 500
Therefore, 2.9 × 10^(22) copper atoms will contain;
(2.9 × 10^(22))/500 reams = 5.8 × 10^(19) reams
D) 1 mol = 6.022 × 10^(23)
Therefore, 2.9 × 10^(22) copper atoms will contain;
(2.9 × 10^(22))/(6.022 × 10^(23)) = 0.048 mol
which of the following best describes a non metal
Answer:
-a nonmetal is a substance that lacks the characteristics of a metal.
-Seventeen elements are generally classified as nonmetals: most are gases (hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon and radon); one is a liquid (bromine); and a few are solids (carbon, phosphorus, sulfur, selenium, and iodine).
14. Which of the following will result in a chemical change?
A. Melting ice to obtain water
B. Evaporating alcohol into vapor
C. Burning coal in a furnace
D. Drying wood in a shed
Help ASAP
Answer:
C
Explanation:
a chemical change is when a substance changes into another.
wood burning turns into heat which would be considered a chemical change
What is temperature
Answer:
Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of heat, a flow of energy, when a body is in contact with another that is colder. Temperature is measured with a thermometer.
Answer:
The degree or intensity of heat present in a substance or object
You should run as an experiment several times to make sure your results are consistent. in the preceding phrase , what does consistent mean
Answer:
To get a final result of experiments, an experiment is repeated several times and the result is noted every time to make sure the results are consistent.
Here the "consistent" meaning is either "same" or "nearby". Consistent results are required in experiments that show constant relation of an experiment to the same principles and the result is not different when performed the same experiment several times.
When performing the same experiment several times, the end result of each experiment should consistent means adhered to the same principle for a successful experiment.
How many atoms are in one body-centered cubic unit cell of a metal?
A) 1.
B) 2.
C) 3.
D) 4.
Answer:
Option B - 2
Explanation:
In Crystal lattices, there are different types of unit cells namely;
- Hexagonal Closest Packed (HCP)
- Face Centred Cubic (FCC)
- Body Centred Cubic (BCC)
- Simple Centred Cubic (SC)
Now, each of them have a coordination number and also number of atoms per unit cell.
For this question, we are restricted to the body-centered cubic (bcc) unit cell which has a coordination number of 8 and contains 2 atoms per unit cell.
Answer:
B) 2.
Explanation:
They have 8 1/8 atoms on the edge that add to get 1 atom. Plus one whole atom inside. 1+1=2
A factor that does no change in an experiment is the.
a. Controlled variable
b. Data
c. Inconstant
d. Independent variable
Answer:
A. Controlled variable
Explanation:
a controlled variable or a constant variable is a variable that doesnt change during an experiment
The noble gas electron configuration for Ca2+ ion is identical with:______.
A. Ne.
B. Kr.
C. Ca.
D. Ar.
Answer:
D. Ar.
Explanation:
The electron configuration of the atom reflects how the electrons are distributed among the various atomic orbitals. Just as for neutral atoms, we use the Pauli exclusion principle and Hund’s rule in writing the ground-state electron configurations of cations and anions.
Ions formed from atoms of most representative elements have the noble-gas outer electron configuration of ns²np⁶. In the formation of a cation from the atom of a representative element, one or more electrons are removed from the highest occupied n shell. The electron configuration of calcium and its ion is as follows:
Ca: [Ar]4s² Ca²⁺ : [Ar]
Which is the formula mass of (NH4)2SO4?
0 96.07 amu
114.12 amu
O 116.17 amu
132.17 amu
Answer:
D. 132.17 amu
Explanation:
The formula mass of a compound can be determined from the formula of the compound thus, from the number each elements present. The formula mass of (NH₄)₂SO₄ is 132.17 amu.
What is formula mass?
Formula mass of a compound is the mass calculated from its formula. Each elements has a definite mass called its atomic mass expressed in g/mol or amu.
Mass number of an element is the sum of number of its protons and neutrons. The actual mass of an element is calculated with respect to the mass of 1/12th of Carbon-12 and it is called relative mass.
Here, the atomic mass of N = 14.006 amu
mass of H = 1.008 amu.
There are 4 hydrogen thus 4 × 1.008 = 4.008 u.
The mass of two units of NH₄ is = (14.006 + 4.008) × 2
= 36.028 u.
Atomic mass of sulfur = 32.6 amu
atomic mass of oxygen = 15.9 amu.
Thus for 4 oxygens = 15.9 × 4 = 63.6 u
The mass of SO₄ unit = 32.06 + 67.6 = 96.2u
Thus the total mass of (NH₄)₂SO₄ = 96.2 + 36.028
= 132.17 amu
Hence, the formula mass of (NH₄)₂SO₄ is 132.17 amu. Thus, option D is correct.
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A runner averages 8 minutes and 25 seconds per mile. What is her average velocity in miles per hour?
8 minutes and 25 seconds is the same as 8.25 in decimal form.
Divide by 60 minutes.
60 / 8.25 = 7.27 miles per hour
Best of Luck!
What is the difference between pure and applied chemistry?
Answer:
Explanation:
The major difference between pure and applied chemistry is the purpose and intent of the study.
Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.
Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application
The major difference between pure and applied chemistry is the purpose and intent of the study.
Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.
Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application.
Thus,the major difference between pure and applied chemistry is the purpose and intent of the study.
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TAn adult with the flu has a temperature of 103.0 ∘F.
Express your answer as an integer.
A brain contains 1.10×10^10 neurons.
Express your answer as an integer.
The time for a nerve impulse to travel from the feet to the brain is 0.46 s.
Express your answer as an integer.
Answer:A integer is a whole number.
An adult with the flu has a temperature of 102°F
A brain contains neurons (moving the decimal point to the right side power of 10 increases........here decimal point is moved to two places to the right side so power of 10 decreases from 10 to 8)
The time for a nerve impulse to travel from the feet to the brain is s. (moving the decimal point to the right side power of 10 increases........here decimal point is moved to two places to the right side so power of 10 decreases from 0 to -2)
Explanation: i am sorry for being 2 year late :(
i hope this answer your question if this is wrong or correct please let me know
What has 2 protons and 2 neutrons in the center of the atom
Answer:
HELIUM
Explanation:
HELIUM HAS 2 PROTON I
PLEASE PLEASE ANY CHEMISTRY EXPERT!! HELP NEEDED. See attached.
Determine whether each pair of compounds forms a homogeneous solution when combined. For those that form homogeneous solutions, indicate the type of forces that are involved.
Answer:
Explanation:
1st) one are homogenous because the have the same kind of force 9 London force ) all the hydrocarbons are nonpolar and have a London force between their molecules
so pentane dissolve in hexane (like dissolves like )
2nd ) CBr4 has a tetrahedral shape its a nonpolar compound (London bond )
but the water is polar molecules has a ( hydrogen bond ) its molecular shape (bent shape) . Both do not dissolve in each other because they have a different kinds of bond so they are not a homogenous solution .
3rd) its a homogenous because the water can dissolve the ionic bonds between the Li ( cation ) and (NO3 -1 anion ).
4th ) here we can say alcohol can dissolve in a little amount why ?
pentane has a London force bond Alcohol has two different parts first part has OH making hydrogen bond which cant dissolve in the pentane different kinds of bonds ,and the other part -CH3 has a London force bond that can dissolves easily in the pentaneso one part dissolves but the other part can't dissolve so the two compound are slightly dissolves in each other that which mean its not a homogenous solution
Convert 542 nanograms to grams.
g.
Answer:
542 nanograms to grams = 5.42E-7g
Explanation:
10. If you were running an experiment to determine the temperature at
which beans sprout the fastest, what would be the independent variable?
A.The number of beans you plant.
B.The height of the sprouts you grow
C.The amount of water you give the beans.
D. The temperature at which each bean is kept.
.
Answer:
The temperature at which each bean is kept
Explanation:
Independent variable is what YOU CHANGE
The temperature at which each bean is kept is the independent variable.
INDEPENDENT VARIABLE:
Independent variable is a variable that is changed or manipulated by the experimenter. The independent variable, which is also called manipulable variable, causes the dependent variable to respond, which is measured or recorded. In an experiment to determine the temperature at which beans sprout the fastest, the independent variable is the temperature at which each bean is kept is the independent variable.Learn more: https://brainly.com/question/17498238?referrer=searchResults
From the following list of elements, select the elements that are likely to form a cation. Choose one or more: A. oxygen B. chlorine C. calcium D. barium E. cesium F. rubidium G. lead H. scandium I. phosphorous From the following list of elements, select those that will always form ionic compounds in a 1:2 ratio with the halogens. Choose one or more: A. phosphorous B. lead C. chlorine D. cesium E. rubidium F. scandium G. barium H. oxygen I. calcium
Answer:
(i). The elements that are likely to form a cation
(C). calcium, (D). barium, (E). cesium, (F). rubidium, (G). lead and (H). scandium
(ii). The elements those that will always form ionic compounds in a 1:2 ratio with the halogens
(B). lead, (G) barium and (I). calcium
Explanation:
Given that,
The following list of elements,
A. oxygen B. chlorine C. calcium D. barium E. cesium F. rubidium G. lead H. scandium I. phosphorous
We know that,
Cation is defined as, an element which is able to donate electron easily and obtained positive ion.
All metal elements able to form cations.
We need to find the elements that are likely to form a cation
Using given list
(C). calcium
(D). barium
(E). cesium
(F). rubidium
(G). lead
(H). scandium
(II). The following list of elements,
A. phosphorous B. lead C. chlorine D. cesium E. rubidium F. scandium G. barium H. oxygen I. calcium
We know that,
All given metal ions can form ionic compound with halogens as 1:2 ratio because all given metals can form +2 charge.
We need to calculate the elements those that will always form ionic compounds in a 1:2 ratio with the halogens
Using given list.
(B). lead
(G) barium
(I). calcium
Hence, (i). The elements that are likely to form a cation
(C). calcium, (D). barium, (E). cesium, (F). rubidium, (G). lead and (H). scandium
(ii). The elements those that will always form ionic compounds in a 1:2 ratio with the halogens
(B). lead, (G) barium and (I). calcium
A average marathon runner run the 26.1 miles in 4 hrs 30 minutes. What is the runners average pace in miles/minutes.
Explanation:
4hr 30 m = 270 min
270/ 26.1 = 10. 34
1 mile per 10.34 mins
how is the caloric value of a food sample determined?
A food sample's caloric value is calculated. By dividing the total weight throughout grams of a particular food by the nutritionists' calculated energy values.
What is calorie?The calorie is an amount of energy that derives from the outmoded caloric concept of heat. Two primary interpretations of "calorie" are frequently used due to historical factors.
The quantity of energy needed to elevate the temperature from one water molecule through one degree Celsius is known as a big calorie, food caloric intake, dietary calorie, simply kilogram calorie. A food sample's caloric value is calculated. By dividing the total weight throughout grams of a particular food by the nutritionists' calculated energy values.
Therefore, a food sample's caloric value is calculated. By dividing the total weight throughout grams of a particular food by the nutritionists' calculated energy values.
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What state of matter is ice in a glacier?
Gas
Liquid
Solid
Transitive
Answer: solid
Explanation:Ice is the solid state of water, a normally liquid substance that freezes to the solid state at temperatures of 0 °C (32 °F) or lower and expands to the gaseous state at temperatures of 100 °C (212 °F) or higher.
The Urbana wastewater treatment plant discharge permit limits the discharge of ammonia/ammonium (NH3/NH4 ). To meet this permit, the ammonium is converted to nitrate (NO3 - ) by biological nitrification in trickling filter towers. The solution entering the nitrification towers contains 15 mg/L of NH4 as N. Write a balanced reaction for the oxidation of NH4 to nitrate,
Answer:
Explanation:
The conversion of ammonium ion into nitrate ion is a two step process which is written below .
2 NH₄⁺ + 3 O₂ = 2NO₂⁻ + 4 H⁺ + 2H₂O
2NO₂⁻ + O₂ = 2 NO₃⁻
This is a two step reaction . These steps are managed by different class of bacteria.
What characteristics identify a substance?
Answer:
All substances can be characterized by their unique sets of physical and chemical properties.
Which of these is a chemical property?
boiling point
odor
ability to rust
color
Answer:
ability to rust
Explanation:
i'm like 90% sure thats correct
For what types of numbers is scientific notation especially
useful? I. very large numbers II. very small numbers
a ll only
b Neither I nor ||
Cl and II
d l only
The correct answer is C: I and ||
Scientific notation is used for very large and very small numbers.
It is more comfortable sometimes to express numbers in scientific notation. The parts of a scientific notation for number are: coefficient, base and exponent.
The larger or smaller the exponent, the more convenient it is to express the number in scientific notation.
Hence, very large and very small numbers are best expressed in scientific notation.
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Based on your observations of the laboratory assignment(s) that produced gases, can you conclude
that the same gas was produced in each assignment? Briefly explain.
Answer:
With the use of same chemicals, same gas will be produced while the use of different chemicals, different gases will be produced.
Explanation:
The same gas was produced in each assignment if the same chemicals are mixed with each other while different gases were produced in each assignment when different chemicals are allowed to mix. If every time, same chemicals and same concentration of chemicals are mixed together, the result will be the same means production of same gas but if different chemicals are allowed to mix, then the product will be the production of different gases.
what are we referring to when we talk about the position of an object
Explanation:
The location of a body with reference to a given point.
. A certain medication is set to deliver through an IV at a rate of 3.0 mg/min. What is this rate in mg/s?
Answer:
[tex]rate=0.05\frac{mg}{min}[/tex]
Explanation:
Hello,
In this case, considering that 1 min equals 60 seconds, we need to perform the unit conversion as shown below in order to compute the rate on mg/s:
[tex]rate=3.0\frac{mg}{min}*\frac{1min}{60s} \\ \\rate=0.05\frac{mg}{min}[/tex]
Best regards.
What is 2.1 x 10^6 + 6.2 x 10^7 in scientific notation
Answer:
2100000 + 62000000
Explanation:
You move the decimal place to the right or left acording to the exponent (right if the exponent in positive, left of the exponent in negative.) Ex: if you're solving for 6.2*10^7 you move the decimal 7 places to the right.
Hope this helped,
-Kiddoo :)
13. Adding up all of the
of all of the individual atoms within one molecule of a compound will determine the molecular mass of the compound.
A. atomic numbers
B. electrons
C. atomic masses
D. protons
A recipe calls for 12 ounces of cocoa powder. All you have are measuring cups. If cocoa powder weighs 0.652 grams per cm3, how many cups of cocoa powder will you need? (1 Tbsp = 15 mL; 1 cup = 16 Tbsp; 1 mL = 1 cc3; 28.4 g = 1 oz.)
Answer:
1 and a half cups
Explanation:
12 ounces is equivalent to 1.5 cups