Answer:
The answer is 7.23 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{4.35 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 7.225913...[/tex]
We have the final answer as
7.23 molesHope this helps you
Students measuring the mass of a metal block record 2.985 g, 3.051 g, 3.102
g, and 3.211 g. Which other measurement of the block's mass would be most
precise?
A. 2.804 g
B. 3.1159
C. 3.418 g
D. 3.509 g
Answer:C - 3.115 g
Explanation:Correct
A student used the Dumas method to determine the molar mass of a volatile material. They placed the container into the ice bath BEFORE all of the material was vaporized. What will happen to their final calculations?
A. The Molar Mass will be too low.
B. The Molar Mass will not be effected.
C. The Molar Mass will be too high.
Answer: the molar mass will be too high
Explanation:
When mixing an acid with water, which of the following must always be done?
A.
Never mix an acid with water, it will explode.
B.
Always add the acid to the water slowly, taking a moment to stir between drops.
C.
Always heat the acid before mixing with water.
D.
Always shake both solutions before mixing.
Answer:
B
Explanation:
Answer:
B. Always add the acid to the water slowly, taking a moment to stir between drops
How many atoms in:
1. NiO -
2. CuO -
3. BaO -
(Pls help ill give brainliest!)
Answer:
I think it might be:
NiO=2
CuO=4
BaO=2
Explanation:
Hope this helps.
The density of ice at its freezing point is 0.917 g/cm3. What is the mass of 2.5 cm3 of ice at this temperature?
A. 1.6 g
B. 2.3 g
C.2.7 g
D.3.4 g
Answer:
The answer is option BExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volume
From the question we have
mass = 0.917 × 2.5 = 2.2925
We have the final answer as
2.3 gHope this helps you
Answer:. 2.3 g
Explanation:
does boron or lithium have a greater first ionization energy ?
Answer:
beryllium has a higher ionization energy because its radius is smaller. boron has a higher ionization energy because its radius is smaller.
What's the ABBREVIATED electron configuration for cobalt?
Answer:
Cobalt/Electron configuration
Explanation:
[Ar] 3d7 4s2
Where is type of precipitation is most likely to form during a thunderstorm
Answer:
hail, btw have a nice day
Answer:
Hail
Explanation:
I got it right on my test
How do you differentiate a neutral solution like water and a strong acid solution like battery acid?
Answer:
If the pH of a solution is less than 7, the solution is called acidic; if the pH is about 7, the solution is neutral; if the pH is greater than 7, the solution is is called basic. In an acidic solution, then, the concentration of hydrogen ions is greater than the concentration of hydroxide ions.
Explanation:
Not sure about the context of the question, but you can check with a ph scale tester.
Is buoyancy a physical or chemical property?
What is the independent variable based on the hypothesis below?
"If acid rain is in water, then fish populations will increase"
Answer:
Acid rain
Explanation:
The independent variable in the hypothesis statement is the acid rain. An independent variable is usually the cause in an experiment.
This variable give rises to the effects observed as the dependent variable.
In the presence of the acid rain, the fish population will increase.
The dependent variable is the fish population or number of fishes.
The independent variable is the acid rain as it is the cause of the effect observed on the fish population.
Group 17 is called the halogen family, and the group to its right is called the noble gases. How are these elements alike and how are they different?
Explanation:
The halogen family and noble gases are similar in just one particular way, they are groups of non-metals. All members of these two groups are categorized as non-metals.
Here are some of the differences between them;
Halogens have 7 electrons in their outermost shell whereas noble gases have 8 electrons in theirs. Halogens are highly reactive elements, noble gases are non-reactive. Halogens are made up of electronegative elements where as noble gases are neither electropositive nor electronegative.hi can someone help me with these 2 :)
Answer:
a and d
Explanation:
ANSWER THIS TO BE MARKED BRAINILEST Water in a beaker measures 250 milliliters. A rock is completely submerged in the water. The water level now reads 375 milliliters. What is the volume of the rock in cubic centimeters? Explain your answer
Answer:
125 cubic meters
Explanation:
Subtract 375-250=125 cubic meters
Whats faster light or sound? PLEASE HELPY ME
Answer:
The answer is that light is faster than sound.
Explanation:
A good example is of lightning and thunder during a thunderstorm.
mark me brainliest!
Do all irreversible reactions go to completion? If so why?
Answer:
True
Explanation:
All irreversible reactions go to completion because the process cannot proceed in the backward direction.
A reversible reaction is one that does not go into completion in one direction.
An irreversible direction completely uses up the reactants to form the products and goes into completion.
These reactions can only proceed in one direction and not both.
The combination of all the organ systems working together make up a(n) _______________________.
1.organ system
2.organism
3.organ
4.cell
Answer:
2
Explanation:
Elements with atomic numbers 7 and 83 have how many valence electrons? *
5 and 5 valence electrons
4 and 8 valence electrons
2 and 2 valence electrons
7 and 83 valence electrons
Explanation:
element with atomic numbers 7 and 83 have 5 and 5 valence electrons
9. Gasoline burns easily if ignited
a) Chemical property
b) Chemical change
c) Physical property
O d) Physical change
Answer:
I think it is chemical change
can someone please help me i don't know these question bc my family celebrates thanksgiving differently. plz and thank you :3
Easy: How many turkeys are consumed on Thanksgiving day in America?
Medium: How long did the first Thanksgiving Celebration last?
Hard: When was the first NFL football game on Thanksgiving?
Fun: Who was the first president to pardon a turkey?
Answer:
Easy 46 million turkeys
Medium three days
Hard: 1934
Fun: The first President on record issuing a "pardon" to his turkey was Ronald Reagan.
Explanation:
hop tis helped
Marissa blows up balloons for a party. She decides how big or small to make each balloon. Why does the air she blows into each balloon take up all the space inside the balloon
Please give formulas of how you solved I only need help on a but if you can do all that I would appreciate that.
Answer:
3.1 moles of ammonia
18.67× 10²³ molecules
Mass = 52.7 g
Explanation:
Given data:
Number of atoms of hydrogen = 5.68×10²⁴ atoms
A) Number of molecules of ammonia = ?
Solution:
First of all we will calculate the number of moles of hydrogen.
1 mole = 6.022× 10²³ atoms
5.68×10²⁴ atoms × 1 mol / 6.022× 10²³ atoms
0.94×10¹ mol
9.4 moles of hydrogen
Moles of ammonia:
3 moles of hydrogen are present in one mole of ammonia.
9.4 moles of hydrogen = 1/3×9.4 =
3.1 moles of ammonia
Number of molecules of ammonia:
1 mole contain 6.022× 10²³ molecules.
3.1 mol × 6.022× 10²³ molecules / 1 mol
18.67× 10²³ molecules
c) Mass of sample = ?
Mass = number of moles × molar mass
Mass = 3.1 moles × 17 g/mol
Mass = 52.7 g
What element has the following electron configuration? 1s 22s 22p 63s 23p 64s 2
Answer:
answer is D
Explanation:
Strontium-90 is one of the products of the fission of uranium-235. This strontium isotope is radioactive, with a half-life of 28.1 yr. Calculate how long it will take for 0.900 g of the isotope to be reduced to 0.170 g by decay.
Answer:
67.6 years is the time the isotope take to decay from 0.900g to 0.170g
Explanation:
The radioactive decay follows first order law:
Ln [A] = -kt + ln[A]₀
Where [A] is concentration after time t,
k is decay constant:
k = ln 2 / t(1/2)
k = ln2 / 28.1 years
k = 0.02467 years⁻¹
[A]₀ = Initial concentration.
We can replace concentration and use the mass of the isotope:
Ln [A] = -kt + ln[A]₀
Ln [0.170g] = -0.02467 years⁻¹t + ln[0.900g]
-1.667 = -0.02467 years⁻¹t
t =
67.6 years is the time the isotope take to decay from 0.900g to 0.170gThe time required for the sample to reduce to 0.170 grams has been 67.75 years.
Half-life can be defined as the times required by the substance to reduce to half of its initial concentration.
The half-life can be expressed as:
Amount left = Initial amount [tex]\times[/tex] [tex]\rm \dfrac{1}{2}^\dfrac{time}{Half-life}[/tex]
From the given:
0.17 g = 0.9 [tex]\rm \times\;\dfrac{1}{2}^\dfrac{t}{28.1}[/tex]
[tex]\rm \dfrac{0.17}{0.9}[/tex] = [tex]\rm \dfrac{1}{2}^\dfrac{t}{28.1}[/tex]
0.188 = [tex]\rm (0.5)^\dfrac{t}{28.1}[/tex]
Taking log on both the sides,
log 0.188 = [tex]\rm \dfrac{t}{28.1}\;\times[/tex] log 0.5
2.411 = [tex]\rm\dfrac{t}{28.1}[/tex]
t = 2.411 [tex]\times[/tex] 28.1 years
Time = 67.75 years.
The time required for the sample to reduce to 0.170 grams has been 67.75 years.
For more information about half-life, refer to the link:
https://brainly.com/question/24710827
In the reaction 2Li(s) + 2H20(1) 2LIOH(aq) + H2(g), which compound is in
the liquid state?
A. H20
B. LiOH
C. Li
O D. H2
Answer:
liquid state is an intermediate phase between solid and gas phase
Answer is A. H20
Answer:
H2O
Explanation:
As H2 is a gas, and the question asks for the liquid state, it'd be H2O.
What is the oxidation number of an element? PLz help. Will give brainliest to correct answer. explanation helpful but not required. Dont answer unless you know
Answer:
its eathe a or c a 50/50 chance
Answer:
Explanation:
its B
(please mark as brainliest if it's correct)
What is the independent variable when testing to see how the viscosity of a liquid affects its flow rate
Answer:
Viscosity
Explanation:
The viscosity of the liquid is the independent variable. The flow rate is the dependent variable in this hypothesis.
The statement given is called the hypothesis. It is a form of scientific guess into a phenomenon.
An independent variable is the cause. A dependent variable is the effect produced. In this hypothesis, the cause of the various flow rate of the liquid is the viscosity. It is therefore the independent variable. The flow rate is the dependent variable.Question 2 (1 point) The chemical formula for an ionic compound represents the a b number of ions in each molecule. total number of ions in the crystal lattice. number of atoms in each molecule simplest ratio of ions that results in an electrically neutral compound.
The chemical formula for an ionic compound represents the simplest ratio of ions that results in an electrically neutral compound. That is option D.
What is an ionic chemical compound?An ionic chemical compound is defined as the type of chemical compound that contains both the oppositely-charged ions of a metal and a nonmetal are attracted reacting with each other to form an ionic bond.
When represented as a chemical formula, it is the simplest ratio of ions that results in an electrically neutral compound.
Learn more about ionic compound here:
https://brainly.com/question/28851190
#SPJ6
which of the following would form an ionic bond?
a.strontium and oxygen
b. sulfur and oxygen
Fill in the coefficients that will balance the following reaction:
(Note: Use 1 as coefficient where appropriate.)
CH4 +
O2 →
CO2 +
H2O
Answer:
CH4 + 2 O2 → CO2 + 2 H2O
Explanation:
There are one mole of O2 on the left side and on the right side there are three moles of O2. And to fix it you would need to make it two moles of O2 to have four molecules of O2 on the left side. Then you would make two moles of H2O to have a total of four moles of O2 on the right. Therefore, CH4 + 2 O2 → CO2 + 2 H2O is the answer.
Answer:
1,2,1,2
Explanation:
hope this helped!