Answer:
The correct answer is D
Explanation:
In an endothermic process, energy travels from the surroundings into the system. The decrease in the temperature on the outside of the bag indicates that energy has moved from the surroundings into the system.
The other answers are incorrect. A bag cannot release “cold” into the surroundings since cold refers to the absence of heat. The surroundings become colder when heat is removed. Option B is incorrect because the cooling is due to the cold pack absorbing heat energy from its surroundings. Option C is incorrect because a cold pack absorbs heat energy from the surroundings, not vice versa.
The surroundings are losing energy and the thermometer is measuring the temperature of the surroundings as the cold pack shows an endothermic process. Therefore, Option (D) is correct.
What is an endothermic reaction?Endothermic reactions are those in which the reactants absorb heat energy from their surroundings to form products. Endothermic reactions reduce the temperature of their surroundings and create a cooling effect. Physical processes can be endothermic in nature as well, for example, ice cubes absorb heat from their surroundings to form liquid water.
Endothermic reactions include the making of chemical bonds through the absorption of energy from the surroundings. On the other hand, exothermic reactions are in which the liberation of heat energy is generated from bond breakage.
The temperature of the cold pack is lower than the temperature of the surroundings. So the heat energy will be traveled from the surroundings to the cold pack.
Therefore, the temperature of the surroundings will fall as heat transfers to the cold pack.
Learn more about endothermic reactions, here:
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Please help me, Thank you!
Answer:
amount of charge
Explanation:
Oxygen and sulfur are both in Group 16, which means they have a -2 charge. They have two more electrons than protons, making the charge of the ion negative.
Hope that helps.
A client is to recieve 2.00g of a drug. The drug comes on a solution that has 500 mg per 5.0 mL. Each vial contains 10 milliliters. How many vials do you need?
Answer:
2 vials
Explanation:
The concentration (C) of the drug in the solution is:
C= 500 mg/5 mL = 100 mg/mL
Each vial with a volume (V) of 10 mL, contains the following mass of drug:
V= 10 mL ⇒ C x V = 100 mg/mL x 10 mL = 1000 mg
As you need 2.00 g, and 1 gram is equivalent to 1000 mg, the mass needed is 2.00 g x 1000 mg/1 g = 2000 mg
Thus, you have to divide the mass you need into the mass of each vial:
(2000 mg)/(1000 mg/vial) = 2 vials
Therefore, you need 2 vials.
A student takes four samples of a white crystalline solid and places each in a well plate. On top of each sample, she carefully places 20 drops of clear mystery liquids A, B, C and D. Her results for each well are as follows:
Liquid A: The solid dissolves quickly.
Liquid B: The solid appears unchanged.
Liquid C: A brownish colored liquid is produced.
Liquid D: Fizzing occurs and the well becomes warmer.
In which well does a PHYSICAL change occur?
Answer:
A
Explanation:
Sorry if wrong
Answer:
Liquid B: The solid appears unchanged.
Explanation:
A is a chemical change, because the solid dissolves away.
C is a chemical change, because the solid changes color.
D is a chemical change, because fizzing occurs.
B is the only solid that seems to remain the same.
Convert 2.072x10^43 atoms element to moles
Given :
Number of atoms of an element, n = 2.072 × 10⁴³ atoms.
To Find :
Number of moles of that element in given number of atoms.
Solution :
We know, 1 mole of any element contains 6.022 × 10²³ atoms.
So, number of moles in given number of atoms are :
[tex]n = \dfrac{2.072\times 10^{43}}{6.022\times 10^{23}}\\\\n = 3.441 \times 10^{19}\ moles[/tex]
Hence, this is the required solution.
how many formula units are in 4.5 moles of NaCl
Answer:
2.71*10^24 formula units in 4.5 moles NaCl
Explanation:
Remark
Make sure you know what a formula unit it. In this case, what it consists of is 1 ion of Na+ Combined with 1 ion of Cl- Together they combine to make NaCl which is ordinary table salt.
1 mole contains 6.02 * 10 ^23 formula units of any chemical -- in this case NaCl.
Therefore 4.50 moles have 4.5 * 6.02*10^23 formula units.
Answer:2.71*10^24
1 Produce a time line for the formation of the atmosphere,
starting with the formation of the Earth 4500 million years ago.
2 Use your research skills to find out:
a more about the ozone hole problem
b what precautions are necessary to prevent an increase in
skin cancers.
Pls help!!!!!
Answer:
1) Well I think you need to research that in G00GLE
Explanation:
2 answer
a) The thinning is most pronounced in the polar regions, especially over Antarctica. Ozone depletion is a major environmental problem because it increases the amount of ultraviolet (UV) radiation that reaches Earth's surface, which increases the rate of skin cancer, eye cataracts, and genetic and immune system damage.
b) Seek the shade, especially between 10 AM and 4 PM.
Don't get sunburned.
Avoid tanning, and never use UV tanning beds.
Cover up with clothing, including a broad-brimmed hat and UV-blocking sunglasses.
Use a broad-spectrum (UVA/UVB) sunscreen with an SPF of 15 or higher every day.
PLEASE HELP ASAP
Which letter represents the moles of a formula in the reaction?
C
E
D
A
B
Answer: b should be the answer just took this test
Explanation:
C.
[2]
Name another chemical which can be used to test for the present of water and state the
colour change.
Answer:
See explanation
Explanation:
There are two chemicals commonly used to test for water. They are;
CuSO4: Anhydrous CuSO4 is white in colour, when it absorbs moisture, its colour changes from white to blue.
CoCl2: Anhydrous CoCl2 is blue in colour. when it absorbs moisture, its colour changes from blue to pink.
In general, what is the trend in atomic radius as atomic number increases in a vertical column on the periodic table?
Answer:
In general, the trend in atomic radius as the atomic number in a vertical column of the periodic table increases is to increase.
Explanation:
The atomic radius represents the distance between the nucleus and the valence shell (that is, the outermost). By means of the atomic radius it is possible to determine the size of the atom.
In groups, the atomic radius increases with the atomic number, that is, down a column. This is because as the atomic number of the elements in a group increases, the number of occupied levels increases, while the effective nuclear charge on the outermost electron is the same. Consequently, the atomic radius increases.
In other words, when you go down in a group (column) of the periodic table, the effective nuclear charge increases, but the number of electrons added with respect to the previous element, the same group increases in a complete shell. The effect of adding new electronic shells is predominant, so they are increasingly distant from the atomic nucleus and the atomic radius is greater when you go down in a group.
So the increase in atomic radius as you go down in a group is due to the increase in electron shells.
5.0g of copper is heated from 20 Celsius to 80 Celsius. How much energy it was used to heat Cu? (Specific heat capacity of Cu is 0.092 cal/g)
Answer:
the energy used to heat Cu is 27.6 Cal
Explanation:
given data
mass m = 5 g
Specific heat capacity of Cu = 0.092 cal/g
temperature T2 = 80 Celsius
temperature T1 = 20 Celsius
solution
we get here energy used to heat Cu that is express as
Q = m × c × ΔT ....................1
so here m = mass and c = specific heat capacity
and ΔT = T2 - T1
so put value in eq 1
Q = 5 × 0.092 × (80 - 20)
Q = 27.6 Cal
so that the energy used to heat Cu is 27.6 Cal
What does x mean- like person x person?
Answer:
× = and
Explanation:
person and person
I've been stuck with this for like an hour, please help.
A 100 gram sample of HG is equal to how many moles of the metal?
Explanation:
Molar mass of Hg = 200.59g/mol.
Therefore Moles = Mass / Molar mass
= 100g / (200.59g/mol) = 0.499mol.
How many moles of nitrogen are in 9.82x10^23 formula units of nitrogen? Please show work!
Answer:
1.63 mols
Explanation:
to convert mols to formula unit, or formula unit to mols, u need the avagadros number which is 6.022*10^23 and the number of mols/formula units
so since the given is formula units, u just have to divide the number by 6.022*10^23 to get the amount of mols
9.82*10^23 / (6.022*10^23) = 1.63 mols
*be careful for sig figs
Wave motion
Vibration
What does the wave shown in the photograph transport from left to right?
Answer:
B. Energy
Explanation:
I took the quiz apix
what is an example of a chemical change that occurs during weathering
Answer:
Hydrolysis is a chemical wheathering process that may affect silicates and carbonates minerals. an example of such a reaction in which water reacts with a silicates minerals is the following: Mg2SiO4 + 4H2O ⇄ 2 Mg(OH)2 + H4SiO. olivine (forsterite) + water ⇄ brucite + silicic acid.
Explanation:
What is the movement of matter due to density differences called?
A a convection current
B a pressure belt
C a climate cycle
D an ocean current
Answer:
A convention current.
Explanation:
the difference between Ionic and Covalent bonding.
is the "flow" of electricity through a
circuit (7)
Answer:
Yes
Explanation:
Answer:
flow of electrons in a circuit or electrical system.
more a electrical system
Explanation:
An electric current is it
Question 3, please help!! 10 points
Answer:
0.68 centiseconds
Explanation:
I looked it up
Answer:
The person above is correct 6800 converted to centiseconds is .68
Explanation:
you have to divide x by 10000 to convert it into centiseconds
in this case x=6800
6800÷10000= 0.68
6 NH4Cl
How many hydrogen atoms are shown?
Answer:
24
Explanation:
6*4=24
I'd love some help please thank you
Answer:
the answer would be B
Explanation:
The move vigorously it is the higher the reactivity so if you put it in order the answer would be B
Your friend cuts his sandwiches in half diagonally because then he gets twice as much
food! What is wrong with his reasoning?
Answer:
It is still one sandwich it doesn't become twice the size just because you cut it, it just becomes one sandwich cut into two
Explanation:
as time goes on specimens in the fossil record become more
a-complex
b-common
c-confusing
d-simple
Answer:
complex
Explanation:
becaause it fits in the words equation I hoped i helped
A mixture of 1.20 mols He, 2.40 mols Ne, 4.80 mols Kr, and 0.60 mols Ar has a total pressure of 600.0 mm Hg. What is the partial pressure of the Kr? Show all work to receive full credit.
Answer: The partial pressure of the Kr is 320 mm Hg.
Explanation:
According to Raoult's Law , the partial pressure of each component in the solution is equal to the total pressure multiplied by its mole fraction. It is mathematically expressed as
[tex]p_A=x_A\times P_{total}[/tex]
where, [tex]p_A[/tex] = partial pressure of component A
[tex]x_A[/tex] = mole fraction of A
[tex]P_{total}[/tex] = total pressure
mole fraction of Krypton = [tex]\frac{\text {Moles of Kr}}{\text {total moles}}=\frac{4.80}{1.20+2.40+4.80+0.60}=0.53[/tex]
[tex]p_{Kr}=0.53\times 600mmHg=320mmHg[/tex]
Thus partial pressure of the Kr is 320 mm Hg
The partial pressure of krypton in the given mixture if total pressure is 600 mmHg is 320mmHg.
How do we calculate partial pressure?Partial pressure of any gas will be calculated by using the Rault's Law as:
p = (x)(P), where
p = partial pressure
P = total pressure = 600 mmHg
x = mole fraction
Mole fraction of krypton = moles of krypton/total moles
x = 4.80 / (1.20+2.40+4.80+0.60)
x = 0.53
Partial pressure of krypton will be calculated as:
p = (0.53)(600) = 320mmHg
Hence partial pressure of Kr is 320mmHg.
To know more about Rault's law, visit the below link:
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Marcellus is using distillation to obtain pure water from seawater. His apparatus is shown below. Put each label in the correct place on the diagram.
Answer:
I hope this photo can help you.
The asthenosphere is the part of the upper mantle just below the lithosphere that os involved in the plate tectonic movement anf isostatic adjustments during as the ice age
Answer:C
Explanation:
Answer:
It's B I promise you
9. What is the process of nuclear fusion? *
(10 Points)
O A. The process of carrying light
B. The process of two atoms fusing
O C. The process of gravity and inertia keeping the universe together
O D. The process of fusing two stars
Answer:
the process of carrying light
According to kinetic theory, all matter is made up of small particles. The particles are constantly
moving
Diagram 1 shows how the particles may be arranged in a solid.
Diagram 1
(a)
One kilogram of a gas has a much larger volume than one kilogram of a solid
Use kinetic theory to explain why.
Enter your answer
Answer:
(a) there are strong forces (of attraction) between the particles in a solid
accept molecules / atoms for particles throughout
accept bonds for forces
1
(holding) the particles close together
particles in a solid are less spread out is insufficient
1
or
(holding) the particles in a fixed pattern / positions
but in a gas the forces between the particles are negligible
accept very small / zero for negligible
accept bonds for forces
1
so the particles spread out (to fill their container)
accept particles are not close together
gas particles are not in a fixed position is insufficient
Explanation:
If you dropped the pencil one more time, do you think
it would be more likely to land near the center or near
the edge of the circle? Include evidence to support
your answer.
how would you explain that after putting in the same amount of heat, the two materials have different temperatures?
Answer:
one material is probably a conductor of heat, which means it absorbs it much better and faster while the other material isn't a conductor and it's taking time to heat up
