Explanation:
When an object undergoes a physical change (solid to liquid, decrease in temperature etc.), the mass of the object remains constant.
When water freezes, the water molecules vibrate closer to one another and there is less space between the molecules.
The same number of water molecules now occupy a smaller volume, therefore their density increases.
The correct answer is the 3rd option.
At the time when the water should be freezed so here the density should be decreased.
What is density?The density refers to the mass of the unit volume with respect to the material substance.
The formula for density should be d = M/v
So here d means the density
And, m means mass
V means the volume
So it should be expressed in units with respect to the units of grams per cubic centimeter.
Hence the last option is correct.
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These two finches share a common ancestor from South America. What is the most likely way that one ancestral finch species will develop into two distinct species?
A The ancestral species was genetically engineered to become two new species
B Groups of the ancestral species became isolated and adapted to different environments.
C. Two individual birds acquired many spontaneous mutations.
D. The ancestral species mated with other species and the offspring resulted in two new species.
Answer:
The correct answer is - B. Groups of the ancestral species became isolated and adapted to different environments.
Explanation:
Two finches Warbler Finch and Woodpecker Finch are two distinct finches are finches from the Galapagos Islands. Both of these finches have a common ancestor from South America.
The most likely explanation of developing two distinct species from an ancestral finch is by bein isolated and developed or adapted according to the challenges and environmental conditions and ultimately become different species after several generations.
I need help really bad with this!!!
For the following:
Highlight each subscript in RED.
Highlight each coefficient in BLUE.
H2O 5Cl2 2Mg 3H2O2
For the following
List the chemical symbols of each element.
Give the number of atoms of each element.
HCl CO2 Na2SO4
Balance the following chemical equations.
1. Cu2O + C → Cu + CO2
2. H2O2 → H2O + O2
Al + Fe3N2 → AlN + Fe
4. Ag2S → Ag + S8
5. ZnS + AlP → Zn3P2 + Al2S3
6. Fe(OH)3 → Fe2O3 + H2O
Given the two chemical equations, highlight in RED the one that is balanced.
7. a. 2Na + Cl2 → 2NaCl
b. 2Na + 2Cl2 → 2NaCl
8. a. C3H8 + 5O2 → 3CO2 + 4H2O b. 2C3H8 + 5O2 → 3CO2 + 8H2O
9. a. 2NH3 + 5O2 → 2NO + 3H2O b. 4NH3 + 5O2 → 4NO + 6H2O
10. a. Y(NO3)2 + GaPO4 → YPO4 + Ga(NO3)2
b. 2Y(NO3)2 + 2GaPO4 → 2YPO4 + Ga(NO3)2
Answer:
Did u get the answers
Explanation:
Help with chemistry please
Which chemical reaction involves the most oxygen atoms?
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Balance
Measured in Newtons
Measured in grams
Property of matter
Spring Scale
Weight
Both
Mass
Cugan 100
drag and drohte
Answer:
The scale reads the tension in the string. The tension in the string is 100 N. This is the force the string must exert up on either of the 100-N weights at either end of the string.
Nothing is moving, nothing is accelerating, so the net force on the spring is zero. Likewise, the net force on either of the 100-N weights is also zero. But that is another question. The spring scale does not measure the net force. The spring scale simply measures the tension, the magnitude of the force exerted by the string.
Explanation:
What is this equation balanced?
CH4 + 2O2 =》CO2 + 2H2O
Answer:
the balanced chemical reaction is provided above .
Explanation:
the given reaction is reaction of methane with oxygen ( or burning of methane in presence of oxygen )
it is highly exothermic, because high amount of heat is evolved in this reaction
The water gained 900 J of energy, what was the energy change of the metal?
Answer:
it lost 900J of energy I will assume and that would mean the change in energy is -900J
Explanation:
Of sulfuric acid, carbonic acid, nitric acid, and hydrochloric acid, which one is considered a weak acid
Answer:
nitric acid is considered as a weak acid
The strong acids are hydrochloric acid, nitric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, perchloric acid, and chloric acid. The only weak acid formed by the reaction between hydrogen and a halogen is hydrofluoric acid
If there is 3% freshwater available on earth, approximately what percentage of it is in ice?
How many oxygen atoms are contained in a sample of aluminum nitrate, Al(NO3)3, with a
mass of 4.285 x 10-21 g? (molar mass of Al(NO3)3 is 213 g mol-l)
a 109
b. 54
c. 9
d. 3
the answer is 9
Explanation:
Explanation: In 1 formula unit of Al(NO3)3 , there are (clearly!) 9 atoms of oxygen, 3 nitrogen atoms, and 1 aluminum atom.
Which of these bonds should be classified as ionic?
A.
Na-O
B.
C-S
C.
H-Cl
D.
Be-S
Answer:
Na-O
Be-S
Explanation:
ionic bonds= metal and non metal
Answer:
Na-O
Explanation:
i solved it in study island and i got this answer correct
HELP PLEASE <3 !!!!!!
Consider the reaction below.
2NH318) N26 + 3H20)
What is the most likely effect to the forward reaction if there is an increase in pressure on this reaction?
O The reactant surface area increases.
O The reaction rate decreases.
O The reaction is not affected at all.
O The reaction stops completely.
Answer:
B. The reaction rate decreases
Explanation:
I just took the pre test and got a 100
Is it technically correct to call ionic compounds molecules?
Answer:
uh yeah I think so technically
Answer:
no
Explanation:
Which of the following could be the speed of an object at rest?
0 m/s
-4 m/s
20 m/s
1 m/s
Answer:
0 m/s
Explanation:
An object at rest stays at rest unless acted upon therefore it can only be 0.
Please actually help me.
Thank you!
Answer:
I say 20 is ur best option
3. __CH4 + __O2-> __CO2 + __H2O
4. __K + __H2O-> __KOH + __H2
Answer:
3: 1 CH4+ 2 O2-> 1 CO2 + 2 H2O
4: 2 K+ 2 H2O -> 2 KOH+ 1 H2
Explanation:
need help with this question plsssss
Answer:
234
Explanation:
Using the table for electrode potential differences (Figure 2) identify the possible composition of the screws responsible for the corrosion observed in the contact area with the copper wire.
320 grams of brass released 5000 J of heat. If it has an initial temperature of 50°C, what is its temperature after releasing the heat? The specific heat capacity of brass is 376 J/kg. *
Answer:
ok:
Explanation:
We have:
[tex]q = mc\Delta T[/tex]
we know that q = -5000 J (it is negative since you release energy)
m = 320 g
and c = 376 J/kg.
We need to be careful before plugging them in. Since the units are J/kg for c, but we are talking about grams for m, we need to convert. I will just divide c by 1000 to get c = 0.376 J/g
We can now plug in:
(-5000 J) = (320 g) * (0.376 J/g) * [tex]\Delta T[/tex]
We can solve that [tex]\Delta T[/tex] = -41.5555
So the final temperature is [tex]T - \Delta T[/tex] which equals around 8.4°C.
HELPPP ASAP PLEASE .
Answer:
ok .
Explanation:
.
What is the temperature (in °C) of a room where the gas has a volume of 0.635 L at 1 atm?
the empirical formula for a compound used as a green paint pigment is C2H3As3Cu2O8. The molar mass of its molecular formula was found to be 1013 grams. What is the molecular formula?
Answer:
Molecular formula = C₄H₆As₆Cu₄O₁₆
Explanation:
Given data:
Empirical formula = C₂H₃As₃Cu₂O₈
Molar mass of compound = 1013 g/mol
Molecular formula = ?
Solution:
Molecular formula = n (empirical formula)
n = molar mass of compound / empirical formula mass
Empirical formula mass of C₂H₃As₃Cu₂O₈ is 506.897 g/mol
by putting values.
n = 1013 / 506.897
n = 2
Molecular formula = n (empirical formula)
Molecular formula = 2 (C₂H₃As₃Cu₂O₈)
Molecular formula = C₄H₆As₆Cu₄O₁₆
Why is it difficult for hydrogen atoms to stick together
Answer:
So, the energy of two hydrogen atoms is lower when the two atoms are together than when the two atoms are apart; that is why they stay together.
Explanation:
Calculate the density of a sample with a mass of 31.6g and a volume of 9.5mL include units in your final answer
Answer:
3.33 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question we have
[tex]density = \frac{31.6}{9.5} \\ = 3.326315...[/tex]
We have the final answer as
3.33 g/mLHope this helps you
Which elements have two valence electrons?
A. Carbon
B. Magnesium
C. Fluorine
D. Sodium
Answer:
Magnesium
Explanation:
Magnesium is in group 2 of the periodic table. The group in which an element is found in tells us the number of valence eletrons it has.
HOPE THIS HELPED
Among the given elements, the element that have two valence electrons is Magnesium. The correct answer is option B.
Valence electrons are the electrons that are present in the outermost shell of an atom that are involved in chemical bonding. The number of valence electrons an atom has is determined by the group number it belongs to on the periodic table.
Magnesium belongs to group 2A on the periodic table, which means it has two valence electrons.
Carbon belongs to group 4A and has four valence electrons, while Fluorine belongs to group 7A and has seven valence electrons. And Sodium belongs to group 1A and has one valence electron.
Therefore, option B. Magnesium is the elements that have two valence electrons.
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how many atoms of oxygen are in 3.45g of Na2SO4
Answer:
HERE
Explanation:Therefore, there will be
6.022
×
10
23
oxygen atoms in
1
mole, or
18 g
of water.
what do water, air and rocks have in common
14. A researcher Is curious to find out what effect classical music has on people's level of relaxation
(as measured by heart rate). She suspects that listening to classical music will make people feel
more calm and relaxed. The researcher lets one group listen to classical music for one hour and
then do a relaxing activity, like reading or drawing for another hour. She lets the other group sit in a
qulet room for two hours (they hear no music). After two hours, she monitors the heart rate of each
participant to measure their level of relaxation.
What is the error in thls experiment design?
A. There are two independent variables: classical music and an additional relaxing activity
B. There are two independent variables: the amount of time and heart rates
C. There are two dependent variables: classical music and an additional relaxing activity
D. There are two dependent variables: the amount of time and heart rates
Answer:
It should be "B"
Explanation:
:) :) :) :) :) :)
Which characteristic is used to classify galaxies?
1. the size of the galaxy
2. the shape of the galaxy
3. the presence of dust and gas between stars
4. the presence of active star formation sites
Answer:
2. the shape of the galaxy
Explanation:
There are four classifications of galaxies and these are: spirals, barred spirals, ellipticals and irregulars. It was Edwin Hubble, an American Astronomer who identified them. They were given such names owing to their shapes. For example, the spiral galaxy looks like it is rotating while the barred spiral galaxy also looks rotating yet it has a bar at the center. Elliptical galaxies have an elliptical shape, similar to that of an elongated circle or an egg. Irregular galaxies don't stick to a particular shape.
Answer:
b
Explanation:
Calculate the new pressure if a 2300 mL of a gas at a pressure of 1.88 atm is allowed to contract to a volume of 2.21 L.
Answer:
V₂ = 0.958 atm
Explanation:
Given data:
Initial volume = 2300 mL (2300/1000 = 2.3 L)
Initial pressure = 1.88 atm
Final volume = (2.21 L + 2.3L) = 4.51 L
Final pressure = ?
Solution;
The given problem will be solved through the Boyle's law,
"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"
Mathematical expression:
P₁V₁ = P₂V₂
P₁ = Initial pressure
V₁ = initial volume
P₂ = final pressure
V₂ = final volume
Now we will put the values in formula,
P₁V₁ = P₂V₂
1.88 atm × 2.3 L = P₂ × 4.51 L
V₂ = 1.88 atm × 2.3 L / 4.51 L
V₂ = 4.32 atm.L / 4.51 L
V₂ = 0.958 atm