A phase change from a solid to a gas is called:
Answer:
sublimation
Explanation:
calculate the maximum mass of ethanol that could be obtained from 30.0g of glucose
Answer:
15.3g
Explanation:
C6H12O6 → 2C2H5OH + 2CO2
1 mol C6H12O6 = 180g
1 mol CH3-CH2-OH = 46g
From 180g glucose ethanol can get = 92g
30g glucose ethanol gives us = (92*30)/180 = 15.33g
Which fossil fuel is the remains of ancient plants?
A. Coal
B. Petroleum
C. Natural Gas
A. Coal
Others are animal remains
The fossil fuel which is the remains of ancient plants is: A. Coal.
Non-renewable energy can be defined as a type of energy that is mainly generated through artificial sources or from the remains of ancient plants.
Hence, a non-renewable energy cannot be replenished or renewed like the renewable energy sources.
Basically, some examples of a non-renewable energy include:
Natural gas.Petroleum.Coal.Other fossil fuels.Coal deposits are typically petrified peat swamps and peat is generated from decaying plants.
Also, coal has been discovered to be a fossil fuel that contain the remains of ancient plants, based on radioactive dating.
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4. Magnesium is the limiting reactant in this experiment. Calculate the theoretical yield of MgO for each trial.
5. Determine the percent yield of MgO for your experiment for each trial.
6. Determine the average percent yield of MgO for the two trials.
Answer: The average percent yield of MgO is 98.59 %.
Explanation:
The chemical equation follows:
[tex]2Mg(s)+O_2(g)\rightarrow 2MgO(s)[/tex]
For Trial 1:The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given mass of Mg = 0.411 g
Molar mass of Mg = 24.3 g/mol
Plugging values in equation 1:
[tex]\text{Moles of Mg}=\frac{0.411g}{24.3g/mol}=0.0170 mol[/tex]
By the stoichiometry of the reaction:
If 2 moles of Mg produces 2 moles of MgO
So, 0.0170 moles of Mg will produce = [tex]\frac{2}{2}\times 0.0170=0.0170mol[/tex] of MgO
We know, molar mass of [tex]MgO[/tex] = 40.3 g/mol
Putting values in equation 1, we get:
[tex]\text{Mass of }MgO=(0.0170mol\times 40.3g/mol)=0.685g[/tex]
The percent yield of a reaction is calculated by using an equation:
[tex]\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100[/tex] ......(2)
Given values:
Actual value of the product = 0.675 g
Theoretical value of the product = 0.685 g
Plugging values in equation 1:
[tex]\% \text{yield}=\frac{0.675g}{0.685g}\times 100\\\\\% \text{yield}=98.54\%[/tex]
Hence, the % yield of the product is 98.54 %
For Trial 2:Given mass of Mg = 0.266 g
Molar mass of Mg = 24.3 g/mol
Plugging values in equation 1:
[tex]\text{Moles of Mg}=\frac{0.266g}{24.3g/mol}=0.011 mol[/tex]
By the stoichiometry of the reaction:
If 2 moles of Mg produces 2 moles of MgO
So, 0.011 moles of Mg will produce = [tex]\frac{2}{2}\times 0.011=0.011mol[/tex] of MgO
We know, molar mass of = 40.3 g/mol
Putting values in equation 1, we get:
[tex]\text{Mass of }MgO=(0.011mol\times 40.3g/mol)=0.443g[/tex]
The percent yield of a reaction is calculated by using an equation:
[tex]\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100[/tex] ......(2)
Given values:
Actual value of the product = 0.437 g
Theoretical value of the product = 0.443 g
Plugging values in equation 1:
[tex]\% \text{yield}=\frac{0.437g}{0.443g}\times 100\\\\\% \text{yield}=98.64\%[/tex]
Hence, the % yield of the product is 98.64 %
Average of a measurement is calculated by given formula:
[tex]Average=\frac{M_1+M_2}{2}[/tex]
where,
[tex]M_1[/tex] = percentage yield for Trial 1 = 98.54 %
[tex]M_2[/tex] = percentage yield for Trial 2 = 98.64 %
Putting values in above equation, we get:
[tex]Average=\frac{98.54+98.64}{2}=98.59\%[/tex]
Hence, the average percent yield of MgO is 98.59 %.
that B) My color is sickle: I have a drop of water in my body when I was given heat, white powder was formed So who am i Lets identify. Write my chemical molecular formula
Explanation:
i don't understood your question ⁉️
and what do u mean by my color is sickle
Give reasons. a. Troposphere is affected maximum by human activities.
Answer:
it is where the ozone layer is locate which is affected by human activities
If 16.4 grams of calcium nitrate is heated as shown in the reaction:
2Ca(NO3)2 -> 2CaO + 4NO2 + O2.
Calculate the volume of nitrogen dioxide produced at STP.
Answer:
7.2
Explanation:
you first have to find the number of moles of nitrogen dioxide by using the number of moles for calcium nitrate and the mole to mole ratios
number of moles of calcium nitrate=mass/mm
=16.4/102
=0.16g/mol
then you use the mole to mole ratios
2 : 4
0.16: x
2x/2=0.64/2
x=0.32g/moles of nitrogen dioxide
then you use the formula for the volume
v=22.4n
=22.4×0.32
=7.2
I hope this helps
hii pls help me to balance the equation and state the symbols thanksss
Ca(s)+ H2O (l)----->H2 +Ca(oH)2
Ca(s)+2H2O(l)----->H2(g)+Ca(oH)2
I hope this helps
sorry if it's wrong
Consider two gases, A and B, which are in a container at room temperature. What effect will the following changes have on the rate of the reaction between these gases?
The temperature is decreased at a constant volume.
A. Increase
B. Decrease
Answer:
A. The rate of reaction will increase or go up
B. The rate of reaction will decrase or go down.
Explanation:
Increasing the temperature will make the gas particles move faster. Faster movement will increase rate of collision between particles to cause a reaction. Decreasing the temperature will cause the opposite to happen.
19. If 23.4 grams of hydrogen gas were produced by the reaction below, how many grams of aluminum chloride were produced? (2 points) 2 Al + 6 HCl yields 2 AlCl3 + 3 H2 516 g AlCl3 774 g AlCl3 1030 g AlCl3 1550 g AlCl3
Answer:
1040
Explanation:
you can use the mole to mole ratios of aluminum chloride and hydrogen gas,you first have to find the number of moles of hydrogen gas..the number of moles of hydrogen gas are 11.7(23.4/2)
2AlCl3+3H2
2 : 3
x :11.7
3x/3=23.4/3
x=7.8g/mol
then find the number of grams of aluminum chloride
m=n×mr
=7.8×133.341
=1040g
I hope this helps and sorry if it's wrong
How many grams of solute is there in 250 mL of a 0.10M CaCl2 solution ?
Answer:
2.775 g
Explanation:
Given that;
Number of moles = concentration × volume
Concentration = 0.10M
Volume =250 mL
Number of moles = 250/1000 × 0.10
Number of moles = 0.025 moles
Also;
Number of moles = mass/molar mass
Molar mass of CaCl2= 111 g/mol
Mass = Number of moles × molar mass
Mass = 0.025 moles × 111 g/mol
Mass= 2.775 g
calculate the mass of magnesium needed to make 25g of magnesium oxide
Explanation:
here's the answer to your question about
state the modern periodic law
Answer:
The modern periodic law states that the physical and chemical properties of the elements are the periodic function of the atomic numbers and electronic configurations. ... This repetition occurs if the arrangement of the elements is in order of their increasing atomic numbers.
Which of the following would not be considered matter?
clouds
trees
rain
air
light
Answer:
light
Explanation:
Have a nice day
Answer:
light
Explanation:
The presence of which gas makes the planets Uranus and Neptune appear blue?
a. helium
b. hydrogen
c. methane
d. nitrogen
Answer:
C. METHANE
Explanation:
The blue color of both the ice giants can be contributed to the presence of methane in their upper atmospheres. Methane absorbs most of the red light incident on the planets which makes them appear blue in color.
PLZ HELP Matthew wants to study how the body responds when the skin is broken. He learns that particles in the blood clump together at the site of the wound to stop the bleeding while the skin heals. Which of the following body systems is involved in carrying the blood to the site of the wound?
A. Cardiovascular
B. Skeletal
C. Respiratory
D. Muscular
Answer:
A, Cardiovascular system
cardiovascular system
C4H9OH have several isomers. Draw structure and IUPAC names of its three isomers.
Answer:
.
Explanation:
why is the Dna molecule able to open up and close?
Answer:
The breaking of the hydrogen bonds due to the force relieves the torsional stress stored in a double helix. As a result, the nucleotide strands rotate more freely about the axis of a helix and start unwinding. ... The DNA unzipping and the DNA unwinding result in a structural transformation from dsDNA to ssDNA.
True or false, the four units that must always be used when using the ideal gas law are liters, atm, Kelvin, and grams
Answer:
False grams is not used
Explanation:
IDEAL GAS LAW
The ideal gas law states that PV = NkT, where P is the absolute pressure of a gas, V is the volume it occupies, N is the number of atoms and molecules in the gas, and T is its absolute temperature.
It is necessary to use Kelvin for the temperature and it is conventional to use the SI unit of liters for the volume. However, pressure is commonly measured in one of three units: kPa , atm , or mmHg . Therefore, R can have three different values.
PLZ HELP ME WITH MY WORK
For his science fair project, Martin studied the growth of trumpet vines. He grew 20 trumpet vines. All of the conditions were the same, except that he grew 10 in a flower bed without support and 10 in a flower bed near a trellis. The stems of the vines near the trellis twisted around the trellis, and these Yines grew tall and seemed much healthier than the vines grown without a trellis. In fact, four of the vines grown without a trellis died. Which characteristic of living things were the trumpet vines displaying as the stems twisted around the trellis?
A. Movement
B. Response to a stimulus
C. Use of energy
D. Reproduction
Answer:
it's B
Explanation:
Climbing plants require an external support to grow vertically and enhance light acquisition. Vines that find a suitable support have greater performance and fitness than those that remain prostrate. Therefore, the location of a suitable support is a key process in the life history of climbing plants
A sample of lithium sulfate, (Li2SO4), has 2.94 x 1023 atoms
of lithium. How many moles of lithium sulfate is the sample?
Answer:
0.245 moles
Explanation:
moles of lithium = 2*moles of Li2SO4
so moles of LI2SO4=2.94*10^23/(2*6*10^23)=0.245
One mole of lithium sulphate contains 1.2 .022 × 10²⁴ atoms. Thus, the number of moles of this compound which contains 2.94 × 10²³ Li atoms is 4.08 moles.
What is one mole?Any substance containing 6 .022 × 10²³ number of atoms is called one mole of that substance. This number is called Avogadro number. Hence, one mole of every elements or molecules contains Avogadro number of atoms.
Similarly, one mole of any compound contains 6 .022 × 10²³ molecules. The weight of one mole of a compound is called its molar mass. The mass of one mole of an element is called its atomic mass.
Hence, one mole of lithium sulphate contains 2 × 6 .022 × 10²³ atoms of lithium. Therefore, the number of moles of lithium sulphate containing 2.94 × 10²³ Li is :
Find more on Avogadro number:
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A solution, such as pure water, with a pH of 7 contains which of the following?
a. Dissolved CO2
b. Equal amounts of hydrogen ions and hydroxide ions
c. Smokestack pollutants such as sulfur dioxide
d. Sodium hydroxide
Answer:
B
Explanation:
Pure water always has equal concentrations of hydrogen and hydroxide ions.
Which statement describes a condensation reaction?
A. monomers break away when one forms a double bond monomers break away with the addition of a water molecule.
B. Two monomers combine when one adds to the double bond of another.
C. Two monomers form a new bond with the loss of a water molecule .
The statement that describes a CONDENSATION reaction is that two monomers form a new bond with the loss of a water molecule . That is option C.
CONDENSATION REACTION involves the combination of two or more molecules(monomers) of water. In reaction, a new bond is usually formed.
The characteristics of a condensation reaction includes:
formation of complex molecules (combination of two smaller monomers),water is usually given off as by product it requires a catalyst for a complete reaction to occurA reaction is called a condensation reaction because a small molecule such as water is released as a byproduct.
A typical example of a condensation reaction is the condensation of amino acids to form dipeptide. The −OH from the carboxyl group of one amino acid combines with a hydrogen atom from the amine group of the other amino acid to produce water.
Therefore, the statement that describes a CONDENSATION reaction is that two monomers form a new bond with the loss of a water molecule. That is option C
Learn more about condensation here:
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what is mean by measurement
Answer:
Measurement is defined as the act of measuring or the size of something. An example of measurement means the use of a ruler to determine the length of a piece of paper. ... Extent, quality, or size as determined by measuring; dimension. A waist measurement of 32 inches.
Explanation:
The comparison o unknown quantity with known standard quantity is called measurement.
The seedlings that we planted on the newspaper cuttings or cotton wool did not grow very well at all, even though they had sunlight and water. What could they not get from the newspaper or cotton wool that plants normally get from soil?
A(n) _____ is a hydrocarbon in which one or more hydrogen atoms is replaced by a -COOH and a -NH2 group. aldehyde carboxylic acid alcohol amino acid
Answer:
Amino Acid
Explanation:
It's part of the Amino group, which are substituted hydrocarbons.
When NH₂ and COOH replaces hydrogens on the same carbon atom in a molecule, an Amino acid is formed.
What group is a COOH?
COOH : a Carboxylic Acid group!
Which of the following elements would you expect to be most reactive, based
on the number of valence electrons it has?
Answer:
C. Lithium
Explanation:
This image describes the trend in reactivity. Group 1 metals are always the most reactive so yeah :)
What is the name of this molecule?
H3C - C ≡ C - CH3
Answer: 1,2,3, or 4-butyne?
Explanation:
The given molecule is
H3C - C ≡ C - CH3
The numbering order is shown below:
H3C - C ≡ C - CH3
1 2 3 4
So, the alkyne group is in the second position.
The carbon chain has four carbons.
Hence, the IUPAC name of the given compound is:
2-butyne.
from the equation 2PbO + C = 2Pb + CO2, detemine which one is reactant is oxidised and which is reduced.
Answer:
Explanation:
C is oxidised because C up to C+4
PbO is reduced because PbO from Pb2+ down to Pb0
Answer:
lead (Pb) is reduced carbon is oxidized
which of the following statements is true about alkali?
A) bases that soluble in water
B) shows a pH value less than 7
C) Ionises in water to form hydroxonium ions
D) Reacts with carbonate salt to release carbon dioxide gas
Answer:
it should be letter c
Explanation:
I hope this help
