Answer:
55
Explanation:
mass number=protons+neutrons
=25+30
=55
Is this true Bc I’m not sure
Answer:
????? questions there no question
Answer:
what
Explanation:
HELP!!!! ASAP!!!!
Complete the following sentences. Energy is required to _______ bonds in a molecule and released when bonds are _______.
Answer:
create and destroyed
Explanation:
its just simple science
Answer:
Create bonds
Broken
Explanation:
Energy is required to created bonds in a molecule and released when bonds are broken.
Energy is needed in chemical reactions to do work.
During bond dissociation, energy is released as a by product.In some cases, they energy is very useful for other processes. Also, when bonds are being formed, the attraction between chemical species stored up chemical energy.When heated, calcium carbonate decomposes according to the equation given below:
CaCO3 --> CaO + CO2
If 50.0 g of CaCO3 react but only 20.0 g of CO2 are recovered, what is the percent yield of this reaction?
90.9%
40.0%
66.7%
250%
Answer:
Percent yield = 90.9%
Explanation:
Given data:
Mass of CaCO₃ = 50.0 g
Mass of CO₂ produced = 20.0 g
Percent yield = ?
Solution:
Chemical equation:
CaCO₃ → CaO + CO₂
Number of moles of CaCO₃:
Number of moles = mass/molar mass
Number of moles = 50.0 g/ 100.1 g/mol
Number of moles = 0.5 mol
Now we will compare the moles of CO₂ with CaCO₃.
CaCO₃ : CO₂
1 : 1
0.5 : 0.5
Mass of CO₂: Theoretical yield
Mass = number of moles × molar mass
Mass = 0.5 mol × 44 g/mol
Mass = 22 g
Percent yield:
Percent yield = ( actual yield / theoretical yield ) × 100
Percent yield = (20.0 g/ 22.0 g) × 100
Percent yield = 0.909 × 100
Percent yield = 90.9%
High percent yield generally indicates a carefully run experiment.
O True
False
in my opinion it's true!!!
A container of nitrogen gas contains 0.55 mol at 7.0 atm and 45°C, and it has a volume of 2.0 L. What volume
will 1.20 mol of nitrogen have at 7.0 atm and 45°C?
Answer:
4.4 L
Explanation:
Given data:
Initial number of mole = 0.55 mol
Initial volume = 2.0 L
Final volume = ?
Final number of moles = 1.20 mol
Temperature and pressure = constant
Solution:
Formula:
V₁/n₁ = V₂/n₂
V₂ = V₁×n₂/n₁
V₂ = 2.0 L ×1.20 mol/ 0.55 mol
V₂ = 2.4 L.mol / 0.55 mol
V₂ = 4.4 L
The volume of the gas is 31.3 L.
Using the formula;
PV = nRT
P = pressure of the gas
V = volume of the gas
n = Number of moles of the gas
R gas constant
T = temperature
To obtain the volume;
V = nRT/P
V = 1.20 mol * 0.082 atmLmol-1K-1 * 318 K/7.0 atm
V = 31.3 L
Learn more about volume:
Can anyone help me ? Tell me if it is right
Answer:
yes
Explanation:
Which describes a chemical property of
copper
Answer:
Atomic number 29
Atomic mass 63.546 g.mol -1
Electronegativity according to Pauling 1.9
Density 8.9 g.cm-3 at 20°C
Melting point 1083 °C
Copper has a melting point of 1083.4 +/- 0.2°C, boiling point of 2567°C, specific gravity of 8.96 (20°C), with a valence of 1 or 2. Copper is reddish colored and takes a bright metallic luster. It is malleable, ductile, and a good conductor of electricity and heat.
Name the following compound: LiBr
Lithium Bromate
Lithum Bromide
Lithium Bromine
Lithium Bromite
HELP!!
H2SO4 is _____.
a base
an acid
a neutral
(The 2 is small and so is 4)
Answer:
Acid
Explanation:
acid
Answer:
An acid
Explanation:
H2OSO4 is Sulfuric Acid
GIVING BRAINLY
this equation describes a chemical reaction : aluminum + iron oxide → aluminum oxide + iron
Which of the following statements about the chemical equation is true? * view attachment for answer choices*
Answer:
C. Iron oxide is a mixture of iron and oxygen
baking soda and vinegar lab demo part 2 mass! 7th grade please help!
Answer:
just watch the video, what does it start with, write that down for each trial, then what does it end with, then starting mass - ending mass is the change mass
what is the gel-like part of the eye?
Answer:
vitreous
Explination:
The vitreous is the gel-like fluid that fills your eye. It's full of tiny fibers that attach to your retina (the light-sensitive layer of tissue at the back of the eye). As you get older, the fibers of your vitreous pull away from the retina.
Answer:
The vitreous
Explanation:
In order for photosynthesis to take place, energy in the form of ______ is required.
A. Sound
B. Light
C. Electricity
D. Kinetic
1. Which of the following is NOT a main tissue type? *
Answer:
there is nothing follow that
Explanation:
In an experiment, the gram atomic mass of magnesium was determined to be 14.7. Compared to the accepted value of 24.3, the percent error for this determination was
39.5
1.65
24.7
98.4
Answer:
The answer is 39.5 %Explanation:
The percentage error of a certain measurement can be found by using the formula
[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\[/tex]
actual mass = 24.3
error = 24.3 - 14.7 = 9.6
We have
[tex]p(\%) = \frac{9.6}{24.3} \times 100 \\ = 39.506172839...[/tex]
We have the final answer as
39.5 %Hope this helps you
Melting chocolate (a change of state) is an example of a
An ionic compound is formed when:
A) an aluminum ion bonds to a calcium ion
B) a cation bonds to an
anion
C) a neutral compound gains an electron
D) at atom gains an electron
Answer:
b is the answer .............
Answer:
The asnswer is c
Explanation:
Gope it helps
A 2.0 sample of N2 occupy 50.0L at 15 degrees Celsius and 640mmHg. What volume will the gas occupy at 45 degrees Celsius and 160mmHg?
Answer:
220.8L
Explanation:
Given parameters:
Initial volume = 50L
Initial temperature = 15°C = 288K
Initial pressure = 640mmHg
Final temperature = 45°C = 318K
Final pressure = 160mmHg
Unknown:
Final volume = ?
Solution:
Using the combined law;
[tex]\frac{p_{1}v_{1} }{T_{1} }[/tex] = [tex]\frac{p_{2}v_{2} }{T_{2} }[/tex]
p,v and T are pressure, volume and Temperature
[tex]\frac{640 x 50}{288}[/tex] = [tex]\frac{160 x v_{2} }{318}[/tex]
160 x 288 x v₂ = 640 x 50 x 318
v₂ = 220.8L
Need Help ASAP
Calculate the pH of:
a) 0.1 M HF Ka = 7.2 x 10-4
b) 1 x 10-3 M HNO3
c) 1 x 10-8 M HCl
a. pH=2.07
b. pH=3
c. pH=8
Further explanationpH=-log [H⁺]
a) 0.1 M HF Ka = 7.2 x 10⁻⁴
HF= weak acid
[tex]\tt [H^+]=\sqrt{Ka.M}\\\\(H^+]=\sqrt{7.2.10^{-4}\times 0.1}\\\\(H^+]=8.5\times 10^{-3}\\\\pH=3-log~8.5=2.07[/tex]
b) 1 x 10⁻³ M HNO₃
HNO₃ = strong acid
[tex]\tt pH=-log[1\times 10^{-3}]=3[/tex]
c) 1 x 10⁻⁸ M HCl
[tex]\tt pH=-log[1\times 10^{-8}]=8[/tex]
How many electrons are in the outer shell of a Li +1 ion?
Answer:
3 electrons
Explanation:
That means there are 3 electrons in a lithium atom. Looking at the picture, you can see there are two electrons in shell one and only one in shell two.
2CO2 + 3H2O + 4Br2
C =
O =
H =
Br =
Explanation:
2CO2 + 3H2O + 4Br2
C = 2
O = 5
H = 6
Br =8
A solution has a pH of 2. Which best describes the solution? A strong acid, a strong base, a neutral solution, a weak base
Answer:
The best solution is Strong acid
Explanation:
add me on snap Andy142512
A solution that has a pH of 2 is a strong acid solution.
Explanation:
The pH of the solution is defined as the negative logarithm of the hydrogen ions concentration in an aqueous solution.[tex]pH=-\log[H^+][/tex]
If the pH of the solution is less than 7 is said to be an acidic solution.If the pH of the solution is equal to 7 is said to be a neutral solution.If the pH of the solution is greater than 7 is said to be an alkaline solution.So, from this, we can conclude that solution with a pH of 2 which is less than 7, hence strong acidic solution.
Learn more about the pH of the solution here:
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the left-right inversion one word answer
Answer:
Lateral Inversion
Explanation:
1.How far can you travel if you drive 4 hours and can average 120 Km/hr?
a.30 Km
b.480 Km
c.80 Km
Answer:
B
Explanation:
D=S×T
=120km/h×4hrs
=480km
Answer:
the answer is b
Explanation:
this is the answer :)
the _ lobe is important in processing visual information.
a. parietal
b. frontal
c. temporal
d. occipital
Answer:
It's D
Explanation:
How do mammals protect their young?
Answer:
Explanation:
Baby pigs, dolphins, bats and elephants all drink milk! Because the babies rely on their mother's milk to live, the mammal mommies have to care for their young. ... Through copying their mothers, baby mammals learn everything they need to survive
Answer:
by be young
Explanation:
wow just use you brain
Mark & Sally were in lab and they were working on a chemical reactions experiment. They mixed 2 liquids together and a white sold color appeared. What can Mark & Sally conclude as their observation?
A chemical change
B physical change
Answer:
A chemical change
Explanation:
From the observation, a chemical change has ensued.
A chemical change is one in which new kind of matter is formed. It is always accompanied by energy changes . This process is not easily reversible.
This process depicted by Mark and Sally is chemical change. This reaction is a precipitation reaction since an insoluble solid has been formed. In chemical changes the process is not reversible.Make the following conversion.
60 dkm = _____ km
6,000
0.060
60,000
0.60
Answer:
0.6
Explanation:
What is a scientific model? How is a scientific model helpful to the brain for relaying a scientific
concept?
Answer: A scientific model is a physical and mathematical and conceptual representation of a system of ideas, events or processes.
ANd also for your second question i dont know what you mean?
Explanation:
Scientists work to recognize and comprehend patterns in our world by applying their scientific expertise to provide predictions about the patterns.
What is the main purpose of scientific model?In a range of scientific specialties, from chemistry and physics to biology and the Earth sciences, research models are employed to explain and forecast the behavior of real things or systems. The ability to depict things that are too little or enormous, explain either past or present, and forecast the future are all advantages of employing model beyond nature.
Why are scientific models important?Models can help you visualize something is difficult to see or understand. Models can help in scientific predictions, process comprehension, and concept communication. Because it frequently includes a variety of hypotheses or facts, an evolutionary theory varies from other general explanations. A science simulation may be used to verify a scientific theory or to demonstrate a scientific model.
To know more about Scientific model visit:
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Which is equal to a temperature of 50 degrees F? 18 degrees C, 46 degrees C, 10 degrees C, 32 degrees C?
Answer:
10 degrees C
Explanation: