Answer:
there is 7 periods and 18 groups
Explanation:
when 3.18 g of copper (||) oxide were carefully heated in a stream of dry hydrogen, 2.54 g of copper and 0.72 g of water were formed determine the number of moles of hydrogen atoms which combine with one mole of oxygen atoms
Answer:
the number of moles of atom is 0.91584
Which statement best describes what would happen to an ecosystem once the sun is removed?
A. The functions within the ecosystem will eventually stop & everything will die off.
B. The ecosystem will continue to thrive; it does not need the sun's energy to work.
C. The ecosystem will look for a different source of energy to use.
D. The ecosystem will instantly stop working.
Answer:
A. The functions within the ecosystem will eventually stop & everything will die off.
Explanation:
Everything is dependent on the sun --starting from the bottom of the food chain, the producers. However, we wouldn't die instantly because "Earth retains heat fairly well, so humans wouldn't freeze instantly."
What is the approximate energy of a photon having a frequency of 4 x 10^7 Hz? (h = 6.6 x 10^-34 J . s)
Answer:
2.64 ×[tex]10^{-26}[/tex] J
Explanation:
I think you should mark it a physics question instead but anyway.
---------------------------------------------------------------------------
The Planck equation should be applied:
E = hv , while E is energy of proton; h is Planck constant; and v is frequency.
E = 6.6 × [tex]10^{-34}[/tex] × 4 × [tex]10^{7}[/tex]
= 6.6 × 4 × [tex]10^{-27}[/tex]
= 2.64 ×[tex]10^{-26}[/tex] J
A 30 kg wrecking ball was dropped from different heights.
30 kg Wrecking ball
Height dropped
Speed at impact
Energy at impact
Distance Object is moved
Trial 1
5m
9.9 m/s
1470 J
0 cm
Trial 2
7m
11.71 m/s
2058 J
3 cm
Trial 3
15m
17.15 m/s
4410 J
55 cm
Trial 4
25m
22.14 m/s
7350 J
120 cm
What is the relationship between drop height and energy at impact?
What did the Curies conclude about radioactivity based on their studies?
A. The amount of radioactivity is an extensive property because it varies as the amount of material varies.
B. The amount of radioactivity is an extensive property because it remains constant as the amount of material varies.
C. The amount of radioactivity is an intensive property because it varies as the amount of material varies.
D. The amount of radioactivity is an intensive property because it remains constant as the amount of material varies.
Answer:
c
Explanation:
A species of kangaroo has a diploid chromosome number of 16. After meiosis, to develop the kangaroo’s sperm or egg, the haploid number would be
. When fertilization occurs, the zygote would again have 16 chromosomes.
Answer:
Just to prove that the persons answer on top of mine is correct :D
Explanation:
Answer:
Explanation:
8
what is a chemical change? and what is a physical change?
In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
A chemical change is a change where something new can be formed and normally can not be changed back. Examples of a chemical change are precipitates being formed, gases being formed, quick temperature change rust, bubbling, foaming, burning, etc. A physical change is a change where nothing new is formed and normally can be changed back. For example you painted a wooden block red. If you want, you can always change the color again. Nothing chemically or permanantly happened to it. More examples of a physical change are; color change, change of state, luster, shape, size, hardeness, etc.
:)
Which sentence is a scientific statement?
A.
There is a substance around us that cannot be detected.
B.
Kids should go to school for 12 years.
C.
Experimentation is the best way to obtain knowledge.
D.
Unicorns once existed on Earth.
E.
There are no living things on the Moon.
B. Kids should go to school for 12 years.
What is a scientific statement?Scientific statements are those statements that must be falsifiable which means that able to be proven false while on the other hand, tautology is a statement that is true. The sun revolves around the earth” is an example of scientific statement because this statement can be falsifiable in the light of evidences and researches. Hypothesis is a statement that may be true or false. We can verify it by doing experiments.
So we can conclude that option B is the sentence that represents a scientific statement.
Learn more about scientific here: https://brainly.com/question/17216882
#SPJ1
A silver ring reacts with compounds containing sulfur in the air to form silver sulfide, a black substance that makes up the tarnish on the surface of silver objects. To remove the tarnish from the ring, students placed it in a pan lined with aluminum foil and added hot water. Baking soda was added to the hot water and stirred. Students made observations about the process. Which observation of this process provides evidence of a chemical reaction?
Question 4 options:
A Hot water heated the aluminum foil.
B The liquid solution changed color.
C The pan was lined with aluminum foil.
D The hot water cooled.
Answer:
c lined with aluminum foil
is methane used as fule
gas true or false
Answer:
its true methane is used as a fuel gas
Explanation:
what would you need to do to calculate the molarity of 10g of NaCl in 2kg of water?
A. convert the 10 g of NaCl to Kg of NaCl
B. Convert the 10g of NaCl to moles of NaCl
C. Convert the 2kg of water to liters of water
D. Convert the 2kg of water to moles of water
Answer:
B) we will convert the 10 g of NaCl into moles.
Explanation:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
we will convert the 10 g of NaCl into moles.
Number of moles of NaCl:
Number of moles = mass/molar mass
Number of moles = 10 g/ 58.44 gmol
Number of moles = 0.17 mol
1 Kg = 1 L
Molarity = 0.17 mol / 2 L
Molarity = 0.085 mol/L
Molarity = 0.085 M
Answer:
B. Convert the 10g of NaCl to moles of NaCl
If 56 grams of nitrogen is mixed with 56 grams of oxygen, what is the pressure of each gas if the total
pressure is 1320 Torrs?
Answer:
pN₂ = 695 torr; pO₂ = 625 torr
Explanation:
Step 1: Calculate the moles of each gas
The molar mass of N₂ is 28.01 g/mol.
56 g × 1 mol/28.01 g = 2.0 mol
The molar mass of O₂ is 32.00 g/mol.
56 g × 1 mol/32.00 g = 1.8 mol
Step 2: Calculate the total number of moles
n = nO₂ + nN₂ = 1.8 mol + 2.0 mol = 3.8 mol
Step 3: Calculate the partial pressure of each gas
We will use the following expressions.
pN₂ = P × X(N₂)
pN₂ = 1320 torr × (2.0 mol/3.8 mol)
pN₂ = 695 torr
pO₂ = P × X(O₂)
pO₂ = 1320 torr × (1.8 mol/3.8 mol)
pO₂ = 625 torr
The model below shows a part of a human body's muscular system.
Muscles are organs that make movement possible. Which organ system is responsible for controlling muscular movement?
A. Endocrine system
B. Skeletal system
C. Nervous system
D. Digestive system
Answer:
you must go to jones im doing the same test
Explanation:
How many grams of NaCl would be required
to react with 346 mL of 0.607 M AgNO3
solution?
Answer:
Mass = 12.27 g
Explanation:
Given data:
Mass of NaCl are required = ?
Volume of AgNO₃ = 346 mL (346 mL× 1L/ 1000 mL = 0.346 L)
Molarity of AgNO₃ = 0.607 M
Solution:
Chemical equation:
NaCl + AgNO₃ → NaNO₃ + AgCl
Number of moles of AgNO₃:
Molarity = number of moles / volume in L
0.607 M = number of moles / 0.346 L
number of moles = 0.607 M × 0.346 L
number of moles = 0.21 mol
now we will compare the moles of NaCl and AgNO₃.
AgNO₃ : NaCl
1 : 1
0.21 : 0.21
Mass of NaCl:
Mass = number of moles × molar mass
Mass = 0.21 mol × 58.44 g/mol
Mass = 12.27 g
(30 points) Ahhhhhhh can someone help me :'))
I'm not smart and I don't understand how to solve this problem:
Octane, one of the major components of gasoline, burns in air according to this unbalanced equation:
C₈H₁₈ (l) + O₂ (g) ----> CO₂ (g) +H₂O
The formula balanced is: 2 C₈H₁₈ (l) + 50 O₂ (g) ----> 16 CO₂ (g) + 18 H₂O
a) What volume of O₂ at STP is needed to burn 702g (1.00L) of octane?
b) What volume of O₂ at 18°C and 0.975 atm is needed to burn 702g of octane?
Answer:
a. 137.93 dm3
b. 150.61 L
Answer:
C₈H₁₈
Explanation:
7. Which part moves the blood away from the heart?
10 bonta
O a. capillaries
b. veins
a carteries
O d. blood vessels
Answer:
Veins
Explanation:
Veins, which usually look blue, return blood to the heart.
If 125.0g of nitrogen is reacted with 125.0g of hydrogen, what is the theoretical yield of the reaction? What is the excess reactant? What is the limiting reactant? Show your work.
The theoretical yield of the reaction : 151.64 g
The limiting reactant : N₂
The excess reactant : H₂
Further explanationReaction
N₂+3H₂⇒2NH₃
A method that can be used to find limiting reactants is to divide the number of moles of known substances by their respective coefficients(mol ratio), and the smaller become a limiting reactant
mass of N₂=125 g
mol N₂(MW=28 g/mol) :
[tex]\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{125}{28}=4.46[/tex]
mass H₂ = 125 g
mol H₂(MW= 2 g/mol) :
[tex]\tt mol=\dfrac{125}{2}=62.5[/tex]
From the equation, mol ratio N₂ : H₂ = 1 : 3
Limiting reactant : N₂ : H₂ =
[tex]\tt \dfrac{4.46}{1}\div \dfrac{62.5}{3}=4.46\div 20.8[/tex]
N₂ : limiting reactant
H₂ : excess reactant
mol NH₃ based on limiting(N₂) (from equation N₂ : NH₃ = 1 : 2)
[tex]\tt mol~NH_3=\dfrac{2}{1}\times 4.46=8.92[/tex]
mass NH₃ (MW=17 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=8.92\times 17=151.64[/tex]
Which diagram shows an element?
Why does salt sprinkled on icy roads cause the ice to melt?
Answer:
The actual reason that the application of salt causes ice to melt is that a solution of water and dissolved salt has a lower freezing point than pure water. When added to ice, salt first dissolves in the film of liquid water that is always present on the surface, thereby lowering its freezing point below the ices temperature. Ice in contact with salty water therefore melts, creating more liquid water, which dissolves more salt, thereby causing more ice to melt, and so on.
How many grams are in 56 L of chlorine gas?
Answer:
Since 1 L equals to 1000 microlitres, and 1 microlitre equals to 1 gram, there are 56 * 1000 = 56000 grams of chlorine gas in 56 L of chlorine gas.
Explanation:
Hope this helped!
What object do you think will take up
more space? Why do you think this?
Answer:
solids
Explanation:
BC they r heavier than liquid and gas
What is causing the Hot Springs to be so hot? What is causing Hot Springs to be so acidic?
Answer:
Hot springs are hot because of geothermal heat. The Hot springs are acidic because hydrogen sulfide and carbon dioxide get in touch with water they evaporate which causes acid.
Explanation:
HELP
1) A 400g sample of alcohol (c = 2.43 J/g°C) at 16°C is mixed with 400g
of water (c = 4.19 J/g°C) at 85°C. What is the final temperature of the
mixture?
Answer:
Explanation:
Given data:
Mass of alcohol = 400 g
Specific heat capacity of alcohol = 2.43 J/g°C
Initial temperature of alcohol = 16°C
Mass of water = 400 g
Specific heat capacity of water = 4.19 J/g°C
Initial temperature of water = 85°C
Final temperature of mixture = ?
Solution:
Equation:
m₁c₁ (T₂-T₁ ) = m₂c₂(T₂-T₁)
by putting values,
400 × 4.19 × (T₂ - 85°C) = 400 × 2.43 × (T₂ - 16°C)
1676 × (T₂ - 85°C) = 972 × (T₂ - 16°C)
Diffraction is a wave property that electrons possess
- true
- false
Answer:
The given statement is "True". A further explanation is provided below.
Explanation:
Diffraction occurs mostly with general noise, with electro-magnetic radioactive material, such as visible region, x-ray, but mostly gamma rays, and with very small moving molecules, such as atomic nuclei, as well as electrons, that also have wavelike characteristics. Yet another side effect of diffraction is because there are no dramatic or rapid shadows.Therefore this obvious response is the right one.
50 POINTS..!!! NEED RHE ANSWER ASAP..!!! consider the original wave at the top of the illustration. compare the original wave to the other four. which wave represents a wave with the same volume but a lower pitch?
a). wave a
b). wave b
c). wave c
d). wave d
Answer:
my best guess is b
Explanation:
typically the lower the pitch the longer the wave line inbetween the inclines are
Match each item with the correct statement below.
a.
Intramolecular force
d.
Intermolecular forces
b.
tetrahedral
e.
London dispersion Forces (LDFs)
c.
linear
____ 1. An intermolecular force that occurs between two molecules of Br2 is formed by?____
____ 2. Is a force that occurs within molecules and compounds.
____ 3. Dipole – dipole, Hydrogen Bond, and London dispersion Forces are examples of what type of force?
____ 4. Is the molecular shape of HI.
__ 5. the molecular shape of CH4
1. LDFs
2. Intermolecular Forces
3. Intramolecular Forces
4. Linear
5. Tetrahedral
Edit: I'm new to this site and idk how to use it properly. I'm not sure about 2 and 3 currently because these forces are between molecules as well so INTERmolecular would be used twice (?)
Can someone please help me with this?-- 18 pts!
What is true about the latent heat of condensation for a substance?
Select all that apply.
The latent heat of condensation will have the same absolute value as the latent heat of vaporization.
The latent heat of condensation will have the same absolute value as the latent heat of solidification.
The latent heat of condensation is a characteristic property that can be used to identify a substance.
The latent heat of condensation will be negative.
The latent heat of condensation is the same for all substances under the same conditions.
The latent heat of condensation will be positive.
Happy Holidays!!
Answer:
latent heat of condensation will have the same absolute value as the latent heat of vaporization. The latent heat of condensation will be negative. The latent heat of condensation is a characteristic property that can be used to identify a substance.
Explanation:
Answer:
energy absorbed or released by a substance during a change in its physical state (phase) that occurs without changing its temperature.
Explanation:
1. True or false, phosphorus-33 is an isotope
Explanation:
it's answer is false
hope it helps you
formula of preparation of sodium hydroxide
The chemical formula of sodium hydroxide is NaOH, and its molar mass is 40.01 g/mol. It is the alkali salt of sodium, and its structure is shown below:
It is an ionic compound consisting of sodium cation (Na+) and hydroxide (OH-) anion.
what do you understand by valency electron and valency shell?
Answer:
total no. of electron present in Valency shell is called valency electron ___________________valency shell is that in which last electron is present