Answer:
the answer is d
Explanation:
1125 J of energy is used to heat 250 g of iron to 55 °C. The specific heat capacity of iron is 0.45 J/(g·°C).
What was the temperature of the iron before it was heated?
55 °C
55 °C
35 °C
35 °C
45 °C
45 °C
20 °C
Answer:
45 °C.
Explanation:
From the question given above, the following data were obtained:
Heat (Q) = 1125 J
Mass (M) = 250 g
Final temperature (T₂) = 55 °C
Specific heat capacity (C) = 0.45 J/gºC
Initial temperature (T₁) =?
The initial temperature of the iron can be obtained as illustrated below:
Q = MC(T₂ – T₁)
1125 = 250 × 0.45 (55 – T₁)
1125 = 112.5 (55 – T₁)
Divide both side by 112.5
1125/112.5 = 55 – T₁
10 = 55 – T₁
Collect like terms
10 – 55 = –T₁
–45 = –T₁
Multiply through by –1
45 = T₁
T₁ = 45 °C
Therefore, the initial temperature of the iron is 45 °C
why is unit of pressure called a derived unit ?? 2) how do you measure the volume of milk?
1. Unit of pressure called a derived unit because it is a combination of base units (kg·m^-1·s^·2).
2. We measure the volume of milk by a instrument called Milk Lactometer.
What is the atomic number of the atom in the diagram above please ?
Answer:
5
Explanation:
The atomic number is the number of protons in an atom. Protons are the positively charged particles in the nucleus. The number of protons define the identity of an element. An element with 5 protons is Boron, no matter how many neutrons may be present.
The atomic number of the atom shown in the diagram is 5.
What is the atomic number?The atomic number of an element refers to the number of protons in the nucleus of its atoms. It uniquely identifies an element and determines its chemical properties.
In the diagram, there are 5 proton numbers in the nucleus of the atom. In other words, this means that the atomic number of the atom is 5.
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HELP PLEASE 15 POINTS
The rate law for a reaction is found to be rate = k[X]4. By what factor does the rate increase if [X] is doubled?
The dehydration of a secondary alcohol, like cyclohexanol, is a mechanism that occurs Choose... . First, the alcohol is protonated to Choose... , creating Choose... intermediate. Then, a Choose... is removed, moving the electrons from that bond to make a Choose... bond.
Answer:
Mechanism
explanation:
have a great day!
What effect does temperature have on reaction rate?
A. An increase in temperature does not change the reaction rate,
B. An increase in temperature keeps the reaction from stopping.
C. An increase in temperature speeds up the reaction rate.
D. An increase in temperature slows the reaction down.
What amount of SeC16 is needed to produce 4.45 mol of chlorine gas in the
reaction Seclo +0 218) —SeO, +3Cl2te)?
2.85 mol
0.95 mol
5.70 mol
8.55 mol
1.49 mol
Answer:
1.48 moles of SeCl6 are needed
Explanation:
Based on the reaction:
SeCl6 + O2 → SeO2 + 3Cl2
1 mole of SeCl6 reacts producing 3 moles of Cl2.
To solve this question we need to use the conversion factor:
1mol SeCl6 = 3mol Cl2
As we want to produce 4.45 moles of Cl2, we need:
4.45 mol Cl2 * (1mol SeCl6 / 3mol Cl2) =
1.48 moles of SeCl6 are neededElements in the same period Question 7 options: A) form bonds with the same type of elements. B) have the same number of protons. C) have the same number of valence electrons. D) have the same principal quantum number.
D is the answer .. I have send u pic also
An example of basic research is A) the development of new plastics that can be recycled. B) the study of the relationship between the amount of automobile emissions gases in the atmosphere and the decomposition of atmospheric ozone. C) the study of the composition of the atom. D) the design of new batteries for electric cars. E) the study of natural compounds in sea animals to look for new molecules that can be used for medicine.
Answer:
C) the study of the composition of the atom.
Explanation:
A research can be defined as a systematic investigation or careful consideration of study with respect to a particular problem using scientific methods such as collection of data, documenting critical information, analysis of data, and the establishment of facts in order to reach new conclusions.
Similarly, a basic research is an approach to research that's typically theoritical and it's aimed at developing a theory, searching for the truth or gain a better understanding about a phenomenon, subject, or basic laws on nature.
In this context, an example of basic research is the study of the composition of the atom.
An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.
Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.
Water is super soluble and this solubility is incredibly helpful for life. Tell me how this solubility helps maintain different processes when it comes to life.
Answer: Water is SUPER soluble and regarded as an universal solvent because it is polar in nature and dissolves most inorganic solutes and some polar organic solutes to form aqueous solutions.
Explanation:
WATER is a substance which is composed of the elements such as hydrogen and oxygen that are combined in the ratio of 2:1. The physical properties of water include:
--> it is a colourless, odourless and tasteless liquid and
--> the boiling point of water is 100°C(this is due to the presence of hydrogen bonding).
The solubility of a solute in a solvent at a particular temperature is the maximum amount of solute in moles or grams that will saturate 1000 dm³ or grams of the solvent.
Water is regarded as a universal solvent BECAUSE it is capable of dissolving many substances. This solubility helps maintain different processes in life such as acting as the solvent which helps cells transport and use substances like oxygen or nutrients.
Chemistry!! Help me! And explain step by step!
1st part is ure answer --> 2M
Given mass -> 58 grams
mass of NaCl -> 58.44 approx -> 58 any
moles given-> 1 moles
[tex]Molarity = \frac{moles}{vol \: in \: lts} [/tex]
[tex]Molarity = \frac{1}{0.5} = \frac{10}{5} \\Molarity = 2M[/tex]
Plz help I will give brainliest
Answer:
1. Fr
2. cl
3.H20
4.2 mole
5. 3
6. c
Which equation describes a physical change? i. H2O(s) ⟶ H2O(l) ii. Na+(aq)+Cl−(aq) +Ag+(aq)+NO3−(aq) ⟶ AgCl(s)+Na+(aq)+NO3−(aq) iii. CH3OH(g)+O2(g) ⟶ CO2(g)+H2O(g) iv. 2H2O(l) ⟶ 2H2(g)+O2(g) v. H+(aq)+OH−(aq)⟶ H2O(l)
Answer:
The answer is "Option i"
Explanation:
In this question, only option (i) is correct, and others were wrong which can be defined as follows:
In option (ii):
[tex]Na^+\ (aq)+Cl^- \ (aq) +Ag^+ \ (aq)+NO_3^- \ (aq) \to AgCl\ (s)+Na^+ \ (aq)+NO_3^-\ (aq) \\\\[/tex]
It is the complete ionic equation.
In option (iii):
[tex]CH_3OH\ (g)+O_2\ (g) \to CO_2\ (g)+H_2O\ (g)[/tex]
It is the combustion reaction but a not balanced equation.
In option (iv):
[tex]2H_2O\ (l) \to 2H_2\ (g)+O_2\ (g)[/tex]
It is the decomposition equation.
In option (v):
[tex]H^+\ (aq) +OH^-\ (aq)\to H_2O\ (l)[/tex]
It is the complete ionic equation.
Under certain conditions, the substance mercury(II) oxide can be broken down to form mercury and oxygen. If 24.1 grams of mercury(II) oxide react to form 22.3 grams of mercury, how many grams of oxygen must simultaneously be formed? Grams oxygen
Answer:
1.76 g
Explanation:
2HgO(s) ==> 2Hg(l) + O2(g)
Number of moles of Hg = 22.3 g/ 201g/mol
= 0.11 moles
From the reaction equation;
2 moles of Hg is formed alongside 1 mole of oxygen
Hence;
0.11 moles of Hg forms 0.11 moles × 1/2
= 0.055 moles of oxygen
Mass of oxygen formed = 0.055 moles of oxygen × 32g/mol = 1.76 g
What is the formula for the compound iodine trichoride?
Answer:
Cl 3 I
Explanation:
Molecular Weight. 233.36. Appearance. Red-orange to brown powder or chunks. Melting Point. 63 °C
Heat transfer takes place when:
A. there is a temperature difference.
B. conduction or convection occurs, but not radiation.
OC. thermal energy is present.
D. None of these
Answer:
A. There is a temperature difference
Explation:
Whenever there is a temperature difference, heat transfer occurs. Heat transfer may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice chest.
Answer:
A.) there is a temperature difference
Explanation:
I got it correct on founders edtell
what is the reactant(s) in the chemical equation below
3CO(g) + Fe2O3(s) 2Fe(s) + 3CO2(g)
Answer:
the reactants are carbon dioxide ,iron, oxygen
PLZ HELP ME WITH MY WORK
How many different elements are there in the molecule C8H11NO2,?
A. 21
B. 2
c. 11
D. 4
Answer:
option C 11
is the correct answer
Any individual offspring produced through a sexual reproduction is always,
Answer:
Any individual offspring produced through asexual reproduction is always: genetically identical to its parent. made up of cells with a cell wall. different from all of its siblings
ASAP
Which of the following describes a characteristic of water that makes it cohesive in nature?
A - It has a partial negative charge on hydrogen and a partial positive charge on oxygen.
B - It has a linear molecular structure with H-O-H arranged in a straight line.
C - It has a vast electronegativity difference between its constituent atoms.
D - It requires a high amount of heat to raise or drop its temperature.
The answer is C.
The vast difference in electronegativity of the oxygen and hydrogen in water, the O-H bond is polar.
The characteristic of water that makes it cohesive in nature is that It has a vast electronegativity difference between its atoms. So, option C is correct one.
Why water is cohesive in nature?The water molecule contains two hydrogen atoms and oxygen atom.
The electronegativity of hydrogen atoms and oxyegen atom is 2.1 and 3.44
Due to high electronegativity of oxygen ,it can attract the bonded pair of electron of hydrogen and form a strong bond and make it cohesive in nature.
What are major characteristics of water?The water molecule have unique characteristics among all some are given below.
Water is polar, with partial positive charge on two hydrogen and partial negative charge on one oxygen.
Water is act as solvent and dissolves the polar and ionic substance.Water has high heat of vaporization.Water has cohesive and adhesive properties.Water has high heat capacity.learn about water molecule Here,
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Select the correct answer.
Which statement accurately describes natural selection?
A.
It ensures that 100 percent of beneficial traits will pass on to the next generation.
B.
It ensures that all individuals with harmful traits are unable to reproduce.
C.
Individuals with beneficial traits are more likely to successfully reproduce than those with harmful traits.
D.
Individuals are all equally likely to successfully reproduce, but the genome will mutate to erase harmful traits.
Answer:
D .
Explanation:
Individuals are all equally likely to successfully reproduce, but the genome will mutate to erase harmful traits.
The number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be
Options:
814 g
0.125 g
0.278 g
337 g
The number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be 0.125g.
How to calculate mass?The mass of a substance can be calculated by multiplying the number of moles by its molar mass.
However, the number of moles of helium must be calculated as follows:
PV = nRT
Where;
P = pressureV = volumen = no of molesR = gas law constantT = temperature0.985 × 0.785 = n × 0.0821 × 301
0.773 = 24.7n
n = 0.773 ÷ 24.7 = 0.031moles
mass of He = 0.031 × 4 = 0.125g
Therefore, the number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be 0.125g.
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Color of the CuCl2 hydrate before heating:
hydrated cucl2 have blue-green colour
A 100 g sample of potassium chlorate, KCIO3(s), is completely decomposed by heating:
2 KCIO3(s) 2 KCl(s) + 3 O2(g)
The oxygen is collected at 89 kPa and 23°C. Calculate the volume, in litres, of oxygen that would be
produced during the decomposition of this sample.
How can you calculate the instantaneous rate of a reaction from a graph of concentrations over time?
Enolase, an enzyme that catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate: Group of answer choices demonstrates a base-catalysis step, where a proton is removed from the substrate. demonstrates an acid-catalysis step, where a proton is added to the substrate. requires two Mg2 cofactors and as such demonstrates metal-ion catalysis. stabilizes the intermediate and transition
Answer:
Requires two Mg²⁺ cofactors and as such demonstrates metal-ion catalysis
Explanation:
Electrostatic catalysis or metal ion catalysis is a catalytic mechanism that makes use of metalloenzymes, such as enolase along with a metal ion which is bound tightly, including, Mo⁶⁺, Ni³⁺, Co³⁺, Mn²⁺, Zn²⁺, Cu²⁺, and Fe²⁺, to undertake a catalysis
For maximal activity, enolase requires the presence of 2 equivalent metal ions in each site which is active
Therefore, the correct option is; requires two Mg²⁺ cofactors and as such demonstrates metal-ion catalysis
Organisms do not adapt as a result of competition for resources.
Answer:
The given statement is False.
The organisms adapt as a result of competition for resources. Different places have different organisms suited for that particular places.
The animals living at a particular place compete for the resources available and the nature selects the organism that has won the competition for resources.
The organisms are evolved as a result of competition for resources
Answer:
I just wanted to say the other person is totally right.
this statement is false.
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 %.
Which of these solutions is acidic?
Answer:
Option a is a solution acidic ([OH⁻] = 7.0x10⁻⁹ M).
Explanation:
To know if a solution is acidic we need to calculate the pH and it must be lower than 7. A value of pH equal to 7 is a neutral solution and a solution with a pH value higher than 7 is a basic solution.
a. For the [OH⁻] = 7.0x10⁻⁹ M we have:
[tex] pOH = -log[OH^{-}] = -log(7.0 \cdot 10^{-9}) = 8.15 [/tex]
Now, the pH is:
[tex] pH + pOH = 14 [/tex]
[tex] pH = 14 - pOH = 14 - 8.15 = 5.85 [/tex]
This solution is acidic (pH < 7)
b. [H₃O⁺] = 8.5x10⁻⁸ M
[tex] pH = -log(8.5 \cdot 10^{-8}) = 7.07 [/tex]
This is not an acidic solution. Is a neutral one (pH around to 7).
c. [OH⁻] = 2.5x10⁻⁶ M
[tex] pOH = -log[OH^{-}] = -log(2.5 \cdot 10^{-6}) = 5.60 [/tex]
Then, the pH is:
[tex]pH = 14 - pOH = 14 - 5.60 = 8.40[/tex]
Hence, this is not an acidic solution. It is basic (pH > 7).
Therefore, option a is a solution acidic ([OH⁻] = 7.0x10⁻⁹ M).
I hope it helps you!
PLZ HELP What human body system includes the stomach, intestines, and teeth?
A. Respiratory system
B. Digestive system
C. Skeletal system
D. Muscular system SUBMIT
Answer:
B
Explanation:
the digestive system
