Answer:
a. The pressure in the flask open to the atmosphere during the vaporization of the unknown liquid is equal to the prevailing atmospheric pressure equivalent to 0.957734 atm
Explanation:
The mass of the empty flask and stopper, m = 53.256 g
The volume of the unknown liquid she adds = 5 mL
The temperature of the water in which she heats up the flask = 98.8 °C = 371.95 K
The mass of the flask and the condensed vapor = 53.780 g
The volume of the flask, V = 231.1 mL
The atmospheric pressure, P = 728 mm Hg
a. We note that the student stoppers the flask after all the liquid has evaporated. Therefore, given that the flask was open to the atmospheric pressure as the liquid evaporates, the pressure of the vapor in the flask is equal to the prevailing atmospheric pressure, or 728 mmHg
Using a calculator, 728 mm Hg is equivalent to 0.957734 atm.
What would it mean if a forecaster claimed, “There will be east winds of 25 to 30 mph."
Answer: It would mean that there is wind originating from the east and blowing west at 25 - 30 mph
Mass = 22g Volume = 2cm3 What is the Density?
Answer:
11g/cm^3
Explanation:
The density of a substance can be found By
density= Mass/volume
From the question
mass = 22 g
volume = 2 cm³
22/2=11
We have the final answer as
11 g/cm³
Answer:
11g/cm^3
Explanation:
It is because the constant formula density is
Density=Mass/ Volume.
Therefore we have
Density=22g/2cm^3
Which is = 11g/cm^3
how did the idea of what a cell was develop overtime
Answer:
experiments
Explanation:
I am not sure but heres my take
Answer:
It was only after the invention of electron microscope that the idea developed
N3- ion name pls help!!
Answer:
N with a charge of (-3) is nitride
Explanation:
What types of elements [metals/nonmetals] are found in each of the compounds?
Not a simple answer please
Explanation:
List of All Elements That Are Nonmetals
Hydrogen (sometimes)
Carbon.
Nitrogen.
Oxygen.
Phosphorus.
Sulfur.
Metals:-
Gold.
Silver.
Iron.
Copper.
Nickel.
Aluminum.
Mercury( Liquid metal)
Titanium.
Fluorine.
what is a chemical equation
Answer:
"Symbolic representation of a chemical reaction in the form of symbols and formulae"
Answer:
A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulas.
Explanation:
Example- Zinc metal reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas. This equation is written as: Zn+H2SO4→ZnSO4+H2.
Which of the following statement is not true?
Answer: 2
Explanation: Greenhouse gases are very important in keeping our planet just right. If we have too many Greenhouse gases it would be too hot, but we can't eliminate all of them or it will be too cold
A solution of 12M HCl is diluted so that it goes from 550mL to a total volume of 1000mL. What is the new concentration of the solution?
Answer:
6.6M
Explanation:
C=concentration
V=Volume
C1V1=C2V2
rearrange formula to find C2
(C1V1)/V2= C2
(12M x 550mL)/1000mL= C2
6600M*mL*/1000*mL* =C2 (cancel units)
6.6M=C2
You are given a 1.55 g mixture of calcium nitrate and calcium chloride. You dissolve this mixture in 20 mL of water and add an excess of 0.300 M silver nitrate. You collect and dry the resulting precipitate and determine it has a mass of 0.535 grams. Calculate the percent calcium chloride in the original mixture.
Answer:
13.4 (w/w)% of CaCl₂ in the mixture
Explanation:
All the Cl⁻ that comes from CaCl₂ (Calcium chloride) will be precipitate in presence of AgNO₃ as AgCl.
To solve this problem we must find the moles of AgCl = Moles of Cl⁻. As 2 moles of Cl⁻ are in 1 mole of CaCl₂ we can find the moles of CaCl₂ and its mass in order to find mass percent of calcium chloride in the original mixture.
Moles AgCl - Molar mass: 143.32g/mol -:
0.535g * (1mol / 143.32g) = 3.733x10⁻³ moles AgCl = Moles Cl⁻
Moles CaCl₂:
3.733x10⁻³ moles Cl⁻ * (1mol CaCl₂ / 2mol Cl⁻) = 1.866x10⁻³ moles CaCl₂
Mass CaCl₂ -Molar mass: 110.98g/mol-:
1.866x10⁻³ moles CaCl₂ * (110.98g/mol) = 0.207g of CaCl₂ in the mixture
That means mass percent of CaCl₂ is:
0.207g CaCl₂ / 1.55g * 100 =
13.4 (w/w)% of CaCl₂ in the mixtureHow are a moon and an asteroid different? (2 points)
a
A moon revolves around an asteroid, while an asteroid rotates around its axis.
b
A moon revolves around a planet, while an asteroid revolves around a star.
c
A moon revolves around a star, while an asteroid rotates around its axis.
d
A moon rotates around its axis, while an asteroid revolves around a planet.
Answer:
B
Explanation:
Asteroid - A rock that rvolves arounf the sun / star.
Moon - A natural satillite that revolves around earth/ planet.
Plutonium is a radioactive material, exposure to which is hazardous to human health, and is one of the few materials that can be used to make a nuclear weapon. The time it takes for half of any initial quantity of plutonium to decay into stable non-radioactive products is roughly:
Answer:
24,000 years
Explanation:
Compute the percentage of error to the nearest tenth in the student’s calculation if the actual specific heat value for aluminum is 0.9J:g*C.
Complete Question:
1. A block of aluminum with a mass of 140 g is cooled from 98.4°C to 62.2°C with a release of 4817 J of heat. From these data, calculate the specific heat of aluminum.
a. Compute the percentage of error to the nearest tenth in the student's calculation if the actual specific heat value for aluminum is 0.9 J/g°C
Answer:
Percent error = 55.56 %
Explanation:
Given the following data;
Mass = 140 grams
Initial temperature = 62.2°C
Final temperature = 98.4°C
Quantity of heat = 4817 Joules.
To find the specific heat capacity;
Heat capacity is given by the formula;
[tex] Q = mcdt[/tex]
Where;
Q represents the heat capacity or quantity of heat. m represents the mass of an object. c represents the specific heat capacity of water. dt represents the change in temperature.dt = T2- T1
dt = 98.4 - 62.2
dt = 36.2°C
Making c the subject of formula, we have;
[tex] c = \frac {Q}{mdt} [/tex]
Substituting into the equation, we have;
[tex] c = \frac {4817}{140*36.2} [/tex]
[tex] c = \frac {4817}{5068} [/tex]
Specific heat capacity, = 0.95 J/g°C
b. To find the percentage error;
Given the following data;
Actual specific heat capacity = 0.9 J/g°C
Experimental specific heat capacity = 0.95 J/g°C
Percent error can be defined as a measure of the extent to which an experimental value differs from the theoretical value.
Mathematically, it is given by this expression;
[tex] Percent \; error = \frac {experimental \;value - actual \; value}{ actual \;value} *100[/tex]
Substituting into the formula, we have;
[tex] Percent \; error = \frac {0.95 - 0.9 }{ 0.9} *100[/tex]
[tex] Percent \; error = \frac {0.5}{0.9} *100[/tex]
[tex] Percent \; error = 0.5556 *100[/tex]
Percent error = 55.56 %
Which observation is true about the result of mixing kernel corn and oil?
A. The kernel dissolved in the oil.
B. The kernel corn floated above the oil
C. The kernel corn did not dissolve completely.
D. The kernel corn settled down at the bottom of the glass.
Answer:
A.The kernel dissolved in the oil.
Jess is baking a cake. Part of the recipe has Jess mix butter and water. He notices that the two substances don't mix. He is confused because water and butter are both covalent compounds. Explain why the butter and water are NOT mixing in the bowl.
Answer:
butter and water don't mix because water is polar and butter is nonpolar
Explanation:
for them to be able to mix they would need to be both polar or both nonpolar.
Which statement about elements is true?
All substances are made up of elements.
There are approximately 50 elements.
An element is made up of different types of atoms.
Most elements are nonmetal.

Answer:
first one is right.
there are 117 elements, so 2nd option is wrong.
elements are made up of one type of atoms, so 3rd is also wrong.
most elements are metal. so 3rd is wrong
Which of the following pictures is a chemical change, and which is a
physical change? Explain in the boxes next to the picture.
Plz explain
Answer:
left is chemical because its chemicals, and right is physical because the ice cream is melting and thats physical
Explanation:
how are the functions of a flower's stamen and pistil related to reproduction?
Answer: the essential parts of a flower
Explanation:
are engaged with seed creation. In the event that a blossom contains both useful stamens and pistils, it is known as an ideal bloom, regardless of whether it doesn't contain petals and sepals. On the off chance that either stamens or pistils are deficient with regards to, the blossom is called imperfect.
Most of the world’s energy comes from what three sources?
These energy sources are called ______________fuels and they are _____________________ resources.
Answers:
Most of the world’s energy comes from what three sources?
Oil, coal, and gas.
These energy sources are called fossil fuels and they are non-renewable resources.
Fuel type: oil
How it's formed: from the remains of ancient marine organisms
Its uses: transportation, industrial power, heating and lighting, lubricants, petrochemical industry, and use of by-products
Fule type: coal
How it's formed: when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial
Its uses: electricity generation, metal production, cement production, chemical production, gasification, and other industrial uses
Fuel type: gas
How it's formed: decomposed organic matter mixed with mud, silt, and sand on the seafloor
Its uses: heating & cooling buildings, cooking foods, fueling vehicles, and electricity generation
Which types of chemical reactions are
considered opposites of one another?
Answer:
Hi
Explanation:
Decomposition reactions are really the opposite of combination reactions. In decomposition reactions, a single compound breaks down into two or more simpler substances (elements and/or compounds).
Explanation:
Decomposition chemical reactions
Decomposition reactions are really the opposite of combination reactions. In decomposition reactions, a single compound breaks down into two or more simpler substances (elements and/or compounds).
The decomposition of water into hydrogen and oxygen gases
and the decomposition of hydrogen peroxide t form oxygen gas and water
are examples of decomposition reactions.
How is it possible for scientists to know the composition of stars without traveling to the star?
Answer:
One of the most common methods used today to determine the composition of stars is spectroscopy.
Explanation:
Spectroscopy is the study of the interaction between matter and electromagnetic radiation as a function of the wavelength or frequency of the radiation.
Write the formula for Zn+2 (SO4)-2
Answer:
Zn2 + SO4 = Zn2(SO4)2
Explanation:
What do glycine, leucine, and lysine all have in common?
They are the building blocks of proteins.
They have an important role in the heart.
They have a role in the functioning of the stomach.
They store equal amounts of energy in their bonds.
Answer:
a, they are the building blocks of proteins.
Explanation:
hope this helps!
~mina
Answer:
A. They are the building blocks of proteins.
(Photo for proof at the bottom.)
Explanation:
Glycine, leucine, and lysine are all amino acids. There are 20 different kinds of amino acids, including the 3 mentioned here. Different amino acids bond together to form different structures, depending on how many there are. Generally, 50 or more amino acids bonded together makes a protein. But there are some exceptions. Amino acids (including glycine, leucine, and lysine) are the building blocks of proteins.
Here's a photo of Edge incase you're doubtful.
Please click the heart if this helped.
What happens as you decrease the temperature of a solution?
A.
The number of solute particles increases.
B.
The number of solute particles decreases.
C.
The rate of dissolution increases.
D.
The rate of dissolution decreases.
E.
The temperature has no effect on the rate of dissolution.
Answer:
D is the answer
Explanation:
What is true of an Arrhenius base?
O A. An Arrhenius base produces OH" ions.
O B. An Arrhenius base accepts OH ions.
O c. An Arrhenius base accepts H+ ions.
O D. An Arrhenius base produces H+ ions.
Answer:
produce OH-
Explanation:
18) What is the following number representing: 10m/s West *
3 points
Force
Acceleration
Mass
Area
Pressure
Velocity
Speed
Impulse
Momentum
Speed
Explanation:
The distance travelled by a body per unit time
Which substance cannot be separated or broken down into simpler substances by chemical means?
table salt
gold wire
candle wax
water vapor
Answer: Gold Wire
Explanation:
Out of all of these options only gold wire is an element, elements are pure and cannot be broken down by any chemical means
hope it helped, good luck :)
how to obtain pure aluminium oxide from sodium aluminate. pls help.
Answer:
By Bayer process.
Explanation:
In the Bayer process, bauxite ore is heated in a pressure vessel along with a sodium hydroxide solution (caustic soda) at a temperature of 150 to 200 °C. At these temperatures, the aluminium is dissolved as sodium aluminate (primarily [Al(OH)4]−) in an extraction process.
The particles of a substance lose energy and change from
a disordered structure with large distances between the particles to
a loosely ordered state.
Which change of state is described?
Answer:
A Liquid
Explanation:
structure with large distance (gas) than goes to a loosely ordered state (liquid)
I hope this helps
What is so important about DNA? Select all correct answers.
A. DNA is found in all organisms and carries instructions to build those organisms
B. DNA found in one organism probably shares similar instructions found in another species
C. DNA is composed of only four bases that repeat in a sequence that is different for each
species
D. Some organisms don't actually have DNA
E. The DNA of each organism is made out of different types of chemicals
Answer:
A and C
Explanation:
DNA is what makes up you and me and DNA is composed of four bases adenine, guanine, thymine, and cytosine. The others are not true.
What do all electrolytes have in common?
They have low melting points.
They are polar molecules.
They have mobile ions in solution.
They are compounds of carbon.
