Answer:
lighter atoms especially hydrogen
Explanation:
At the heart of the stars, nuclear fusion merges lighter atoms especially hydrogen together in the nucleus of atoms to create new elements.
During nuclear fusion small atomic nuclei combines to form larger ones with the release of a large amount of energy.
The energy released provides the needed temperature for another set of hydrogen atoms to fuse. This process is in turn yields another set of helium atom which releases a lot of energy.
A chain reaction progresses which leads to the formation of new elements.
Base changes phenolphthalein to pink it is true or false
Answer:
It’s false
Explanation:
it could be true if the question mentioned alkaline solution
Answer:
True
Explanation:
Phenolphthalein is colorless in the presence of an acid and turns pink in the presence of a base.
What is the volume of 4.78g of O2 gas at STP?
Answer:
Explanation:
The trick here is to realize that if you know the volume of a gas at STP, you can use the fact that
1
mole of any ideal gas occupies
22.7 L
under STP conditions to calculate how many moles of gas you have in your sample.
Under STP conditions:
1 mole of an ideal gas = 22.7 L
−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
In your case, you know that your sample of gas occupies
2.28 L
under STP conditions, which are currently defined as a pressure of
100 kPa
and a temperature of
0
∘
C
.
This means that your sample will contain
2.28
L
⋅
molar volume of a gas at STP
1 mole gas
22.7
L
=
0.10044 moles gas
Now, the molar mass of the gas is the mass of exactly
1
mole of the gas. In your case, you know that you get
3.78 g
for every
0.10044
moles, which means that you have
1
mole
⋅
3.78 g
0.10044
moles
=
37.6 g
Since this is the mass of
1
mole of gas, you can say that the molar mass of the gas is
molar mass = 37.6 g mol
−
1
−−−−−−−−−−−−−−−−−−−−−−−
Which instrument is used to measure mass?
Answer:
Balance
Explanation:
hope i helped
Marble chips react with dilute hydrochloric acid to produce carbon dioxide gas. The rate of this reaction can be changed by changing the size of marble chips.
Describe experiments to investigate what effect using smaller marble chips has on the rate of this reaction.
Answer:
See explanation
Explanation:
We know that surface area is an important determinant factor in the study of reaction rate. This is the reason why finely divided marble chips react faster than lumps of marble in the reaction between marble chips and dilute HCl.
Now imagine that i have a lump of marble and i have finely divided marble. Then i also have a solution of 0.5 M dilute HCl. If i introduce 1g of the lump of marble into 250 ml solution of the 0.5 M HCl in one beaker and introduce 1g of finely divided marble into another 250 ml solution of 0.5 M HCl in a separate beaker, we will notice that the finely divided marble chips reacts faster as evidenced by the quicker effervescence of CO2 gas from the later compared to the former.
Hence, smaller marble chips reacts faster with dilute HCl than a lump of marble.
Answer:
yes the above given answer is absolutely correct I agree with u man on the above.
How many molecules of water of water are in a 821.3 g sample
Answer: 2.744 x 1025 molecules
Consider the double replacement reaction given below: HgNO3(aq) + KBr(aq) → HgBr (??) + KNO3(??)The state of matter for HgBr would be
Answer: The state of maater for HgBr is solid.
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
A double displacement reaction in which one of the product is formed as a solid is called as precipitation reaction.
The balanced chemical equation is:
[tex]HgNO_3(aq)+KBr(aq)\rightarrow HgBr(s)+KNO_3(aq)[/tex]
66 A student wants to design a controlled experiment to solve the following problem: When placed in a freezer, will hot water or cold water reach 0°C faster?
The student plans to place two containers with equal masses of water (one hot and one cold) in the same freezer in the classroom.
a List three conditions the student should keep constant for the hot-water and cold-water setups when planning this experiment. [3]
b For each condition you name, give a scientific reason why the condition needs to be the same for both the hot-water and cold-water setups
Answer:
Explanation:
is guiZ
Balance the following equations:C(s) +CO2(g)- CO(g)
Answer:
C(s)+CO₂(g)→2CO(g)
Explanation:
Basically you’re adding the compounds until they’re equal on both sides
During the naval battles of the South Pacific in World War II, the U.S. Navy produced smoke screens by spraying titanium tetrachloride into the moist air where it reacted according to the equation:
TiCl4 + H2O TiO2 + HCl
a. How many moles of H2O are needed to react with 6.50 moles of TiCl4? (13.0)
b. How many moles of HCl are formed when 8.44 moles of TiCl4 react? (33.8)
Explanation:
The reaction given is;
TiCl4 + H2O --> TiO2 + HCl
The reaction is not balanced, upon balancing it is given as;
TiCl4 + 2H2O → TiO2 + 4HCl
a. How many moles of H2O are needed to react with 6.50 moles of TiCl4?
From the reaction;
1 mol of TiCl4 requires 2 mol of H2O
6.50 mol of TiCl4 would require x mol of H2O
1 = 2
6.5 = x
x = 6.5 * 2 / 1 = 13.0 mol
b. How many moles of HCl are formed when 8.44 moles of TiCl4 react?
From the equation of the reaction;
1 mol of TiCl4 reacts to form 4 mol of HCl
8.44 mol of TiCl4 reacts to form x mol of HCl
1 = 4
8.44 = x
x = 8.44 * 4 / 1 = 33.76 mol
If I have one mole of sulfur, how many grams would it weigh?
Answer:
32.06 grams
Explanation:
One mole of sulfur is equal to 32.06 grams of sulfur.
Answer:ok
Explanatio
heres the answer 32.065 grams because 1 mole is equal to 1 moles Sulfur
5. Geologists think that the inner and outer cores of Earth consist of
iron and nickel.
Answer:
is this true/false? if so its true.
Explanation:
Which of the following is true about homogeneous mixtures?
They consist of two or more phases; They are always liquids; They are known as solutions; They have compositions that never vary
Answer:
Option 3: They are known as solutions
Explanation:
Examples of homogenous mixtures include:
soapy watertea or coffee that's breweda mixture of water and alcoholbloodairquartznitrogenI hope this helps :)
1. Which of these is NOT found in the nucleus of an atom?
neutrons
protons
electrons
the mass of the atom
Answer:
Electrons
Explanation:
Answer:
Electrons are not found in the nucleus for they are orbiting the atom.
True or false for these!!!! Please help
What is the percent yield of this reaction if 22.o g of Mgl2 is produced by the reaction of 25.0 g of Mg with 25.0 g of l2?
% yield = 80.719
Further explanationGiven
22.0 g of Mgl₂
25.0 g of Mg
25.0 g of l₂
Required
The percent yield
Solution
Reaction
Mg + I₂⇒ MgI₂
mol Mg = 25 g : 24.305 g/mol = 1.029
mol I₂ = 25 g : 253.809 g/mol = 0.098
Limiting reactant = I₂
Excess reactant = Mg
mol MgI₂ based on I₂, so mol MgI₂ = 0.098
Mass MgI₂ (theoretical):
= mol x MW
= 0.098 x 278.114
= 27.255 g
% yield = (actual/theoretical) x 100%
% yield = (22 / 27.255) x 100%
% yield = 80.719
The phase that occurs beyond the critical point is:
A. Liquid
B. Solid
C. Gas
D. All of the above
Answer:
C. Gas
Explanation:
A supercritical fluid occurs beyond the temperature of critical point, wherein the state matter transitions from liquid to gaseous phase interchangeably. Whereas, triple point occurs when all three states of matter: solid, liquid nd gas; coexist.
Hence the answer to the question is Gaseous phase/
I hope you found this helpful.
What is the charge of an electron?
A-negative
B-neutral
C-positive
D-none of these
How do I balance "Lithium hydroxide + hydrogen acetate --> lithium acetate + water"
Answer:
LiOH+CH3COOH=C2H3LiO2+H2O balanced equation
Explanation:
lithium hydroxide-> LiOH
hydrogen acetate->CH3COOH
lithium acetate->C2H3LiO2
water->H2O
LiOH+CH3COOH=C2H3LiO2+H2O
Li=1,O=3,H=5,C=2 --> Li=1,O=3,H=5,C=2
the two sides have same numbers so it is balanced.
3. All the deer in Horry County represent which of the following?
species
biome
population
community
Answer:
community
Explanation:
Answer:
The correct answer is population. I took the test and got it right.
The nucleus of a fluorine atom has a charge of?
A. +19
B. 0
C. +9
D. +1
Answer: B
Explanation: A fluorine atom has nine protons and nine electrons, so it is electrically neutral. (neutral =0)
The nucleus of a fluorine atom has a charge of zero as the atom has equal number of positive and negative charges.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
Learn more about atom,here:
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The combination of all the forces on an object is called?
Answer:
net force
Explanation:
6.900x10^10 ÷ 4.000x10^8
Answer:
1.725e+18
Explanation:
PLZ HELP ME IM FAILING!
Everything you need to know about the question is on the photo
Answer:
C. NH₄Cl
Explanation:
The compound with the element ratio 1 : 4 : 1 from the given choices is NH₄Cl.
An element is a pure substance made up of distinct number of atoms. Elements are unique and are different from other elements because of the nature of their atoms.
We often delineate an element using chemical symbols.
In the compound NH₄Cl;
There are 3 elements:
Number of atoms
N 1
H 4
Cl 1
How many gallons of water would be in a container that is 256 millimeters X 20 inches X.045 meter.
10
If velocity is positive, which would most likely yield a negative acceleration?
O O OO
A final velocity that is faster than an initial velocity.
A time that is less than a half hour.
An initial velocity that is faster than a final velocity.
A time that is greater than a half hour.
Answer:
An initial velocity that is faster than a final velocity
Explanation:
The relationship between velocity and acceleration is given as follow;
Acceleration = Change in velocity / Time
Change in Velocity = Final Velocity - Initial Velocity
From the formular, time is not able to affect the sign of the acceleration.
A negative acceleration is also referred to as deceleration and this occurs when there is a drop in velocity.
A drop in velocity occurs when the initial velocity is faster than the final velocity.
How does adaption allow mice with the mutation to survive better in some areas
Answer: Mutations can cause instant adaptations, while natural selection is the process by which adaptations occurs over a series of generations. Adaptations are changes or processes of changes by which an organism or species becomes better suited for its environment. A mutation is an alteration of the DNA sequence.
What might the student have done that caused this
error? List all possible causes.
Answer:
The capillary tube was too close to the bottom of the beaker.
The ruler may have moved.
Water got into the capillary tube.
The temperature was not allowed to equilibrate in the 2-4 minutes.
Explanation:
The boiling point of ethanol is 78.3 degrees Celsius. The boiling point of
ethanol on the Kelvin scale is approximately... *
Answer:
K = 351.3
Explanation:
The relationship between the Celsius scale and kelvin scale is;
K = 273 + C
Since the Celsius temperature = 78.3
The kelvin temperature is given as;
K = 273 + 78.3
K = 351.3
How many molecules are in 2.91 X 1022 atoms of He
Answer:
Explanation:
1 mole of oranges contains 6.02 x1023 oranges. 1 mole of helium gas contains 6.02 x1023 helium atoms. 1 mole of water contains 6.02 x1023 water molecules.
...
Answer:
25194.56
Explanation:
You'll need a scientifuc calculator
2.91*10^22*1 = 2.91E22
2.91E22-/6.02*10^23=25194.56
6.02*10^22 Is the Mole number
The CO2 that builds up in the air of a submerged submarine can be removed by reacting it with sodium peroxide. 2 Na2O2 (s) + 2 CO2 (g) → 2 Na2CO3 (s) + O2 (g)
If a sailor exhales 150.0 mL of CO2 per minute at 20oC and 1.02 atm, how much sodium peroxide is needed per sailor in a 24 hr period?
Answer: The sodium peroxide needed per sailor in a 24 hr period is 674 grams.
Explanation:
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 1.02 atm
V = Volume of gas = 150.0 ml = 0.15 L
n = number of moles of carbon dioxide = ?
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature =[tex]20^0C=(20+273)K=293K[/tex]
[tex]n=\frac{PV}{RT}[/tex]
[tex]n=\frac{1.02atm\times 0.15L}{0.0821 L atm/K mol\times 293K}=0.006moles[/tex]
[tex]2Na_2O_2(s)+2CO_2(g)\rightarrow 2Na_2CO_3(s)+O_2(g)[/tex]
According to stoichiometry:
2 moles of carbon dioxide require = 2 moles of sodium peroxide
Thus 0.006 moles carbon dioxide require= [tex]\frac{2}{2}\times 0.006=0.006[/tex] moles of sodium peroxide
Mass of sodium peroxide needed for 24 hour=[tex]moles\times {\text {Molar mass}}=0.006mol\times 78g/mol\times 24\times 60=674g[/tex]
Thus sodium peroxide needed per sailor in a 24 hr period is 674 grams.
The amount (in grams) of sodium peroxide needed per sailor in a 24 hr period is 673.92 g
Determination of the mole of CO₂Volume (V) = 150 mL = 150 / 1000 = 0.15 L Temperature (T) = 20 °C = 20 + 273 = 293 KPressure (P) = 1.02 atmGas constant (R) = 0.0821 atm.L/Kmol Mole of CO₂ (n) =?Using the ideal gas equation, we can obtain the mole of CO₂ as follow:
n = PV / RT
n = (1.02 × 0.15) / (0.0821 × 293)
n = 0.006 mole
How to determine the mole of Na₂O₂ required2Na₂O₂ + 2CO₂ → 2Na₂CO₃ + O₂
From the balanced equation above,
2 moles of CO₂ required 2 moles of Na₂O₂.
Therefore,
0.006 mole of CO₂ will also require 0.006 mole of Na₂O₂.
How to determine the mass of Na₂O₂ required Mole of Na₂O₂ = 0.006 mole Molar mass of Na₂O₂ = (23×2) + (16×2) = 78 g/mol Mass of Na₂O₂ =?Mass = mole × molar mass
Mass of Na₂O₂ = 0.006 × 78
Mass of Na₂O₂ = 0.468 g per minute
Mass of Na₂O₂ required for 24 h = 0.468 × 24 × 60 = 673.92 g
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