Answer:
The correct answer is - alpha particle and positron.
Explanation:
In this question, it is given that, 38^88Sr decays to 34^84Kr, which means there is an atomic number decrease by 4, 38 to 34, and atomic mass decreases by 4 as well 88 to 84.
A decrease in the atomic mass is possible only when there is an emission of the alpha particle as an alpha particle is made of 2 protons and 2 neutrons. If an atom emits an alpha particle, there is a change in atomic number as it decreases by two, and its mass number decreases by four.
So after the emission of an alpha particle, the new atom would be
38^88Sr=> 36^84X => 34^84Kr
so there is also two positron emission that leads to decrease in atomic number by one with each emission:
38^88Sr=> 2^4He+ 36^84X => 36^84X + 2(1^0β+) => 34^84Kr
Positron decay is the conversion of a proton into a neutron with the emission of a positron that causes the atomic number is decreased by one, which causes a change in the elemental identity of the daughter isotope.
Consider the terms elements, compounds, and mixtures. What do you think each of
these is?
Answer:
Explanation:
Element -
It is the basic unit of matter, which cannot be broken down into substances by any way but can be combined to form new substances.
It is a pure substance.
It classifies into metals, non-metals, metalloids and noble gases.
Example - Hydrogen, Carbon, Oxygen
Compounds -
It is a combination of two or more elements.
It is a pure substance.
Through chemical reactions, they can be broken down into metals.
Example - Water, Carbon dioxide
Mixtures -
It is a combination of two or more elements or compounds or both.
The substances combined in a mixture are in a particular ratio.
Example - Chalk powder, Washing Soda
Please help :)
A chocolate chip cookie recipe calls for 0.050 moles of baking soda (NaHCO3). How many grams should the chef mass out?
According to the mole concept, 4.2 g of baking soda should be weighed out.
What is mole concept?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
Baking soda has molar mass of 84 g /mole, thus mass is calculated using number of moles formula which is mass= molar mass×number of moles, which is mass=84×0.050=4.2 g.
Thus,4.2 g of baking soda should be weighed out by chef.
Learn more about mole concept,here:
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Consider these chemical equations.
N2(g) + 3H2(g) → 2NH3(g)
C(s) + 2H2(g) → CH4(g)
4H2(g) + 2C(s) + N2(g) → 2HCN(g) + 3H2(g)
Which equation(s) do you need to reverse in order to calculate the overall equation for the formation of HCN and H2 from NH3 and CH4? Check all that apply.
Answer:
A. N2(g) + 3H2(g) Right arrow. 2NH3(g)
B.C(s) + 2H2(g) Right arrow. CH4(g)
Explanation:
Answer:
a and b
Explanation:
second question
miultiplu second eq by 2
how many protons electrons and neutrons are present in the following atoms
Answer:the element is potassium
the proton and electron is 19 and the nuetron is 19
Explanation:
Answer:
The atomic number gives the number of protons 19
p = 19
The atomic mass is the sum of the protons and neutrons
p+n = 39 p = 19
Put p into the equation and solve for n the neutrons
19+n = 39
Subtract 19 from both sides
19-19+n = 39-19
n = 20
The number of electons equal the number of protons in a neutral atom. The positive charge equal to the negative charge. The negative charge is the number of electons. This ion has a charge of +1. So solve for the negative charge.
-19+1 = -18
The negative charge is -18 so
e = 18
Which redox reaction would most likely occur if silver and zinc metal were
added to a solution that contained silver and zinc ions?
Click for a reduction potential chart
O A. Zn2+ + 2Ag → Zn + 2Agt
B. Zn2+ + 2Agt → Zn + 2Ag
C. Zn + 2Ag → Zn2+ + 2Ag+
D. Zn + Ag? → Zn2+ + 2Ag
Answer:
Zn²⁺ + 2Ag → Zn + 2Ag⁺
Explanation:
According to the reduction potential chart, silver ion (Ag⁺) is a stronger oxidizing agent than zinc (Zn), which is a reducing agent the compared to silver
Therefore, the redox reaction that will occur is that the zinc, Zn, will be oxidized to Zn²⁺ ion, while the silver, Ag²⁺ ion will be reduced to silver deposits Ag, therefore, the zinc will displace the silver in the solution containing silver and zinc ions because zinc is higher than silver in the reactivity series
The reduction potential Zn → Zn²⁺ + 2e⁻ = +0.76
The reduction potential for Ag⁺ + e⁻ → Ag = +0.8
Given that redox reactions are reversible, we get the following likely redux reaction:
Zn(s) + 2Ag⁺(aq) ⇄ 2Ag(s) + Zn²⁺(aq)
Zn²⁺(aq) + 2Ag(s) → Zn(s) + 2Ag⁺(aq) is the reaction most likely to occur.
9. During an experiment the students prepared three mixtures A)Starch in water B) Sodium chloride solution C) Tincture of Iodine. i) Students observed a visible beam of light through mixture A. Why? ii) Tincture of lodTe did not show Tyndall effect. Explain reason. ill) How can you relate particle size to Tyndall effect?
Answer:
See explanation
Explanation:
Tyndall effect refers to the scattering of light in a solution. Tyndall effect occurs when the size of particles in the solution exceeds 1 nm in diameter. Such solutions are actually called false solutions.
In tincture of iodine, the size of particles in solution is less than 1 nm in diameter hence the solution does not exhibit Tyndall effect. Hence, tincture of iodine is a true solution.
Therefore, if the size of particles in solution exceeded 1nm in diameter, Tyndall effect is observed.
17. The name of the reaction that produces esters is
A. addition.
B. anionic initiated polymerization.
C. radical initiated polymerization.
D. dehydration
Answer:
the name of reaction that produces esters is dehydration.
Question 6 of 10 What is the function of mitochondria? O
A. The mitochondria use sugars as fuel to produce energy.
B. The mitochondria direct the cell's activities and hold its DNA.
C. The mitochondria surround the cell and control which materials come into and out of the cell.
D. The mitochondria use sunlight to produce sugars. SUBE
Answer:
A. The mitochondria use sugars as fuel to produce energy.Explanation:
The most prominent function of mitochondria is to produce the energy currency of the cell, ATP (i.e., phosphorylation of ADP), through respiration and using sugar as fuel, and to regulate cellular metabolism .
What is required for dynamic equilibrium?
A. A closed system.
B. The forward and backward reactions occur under the same conditions.
C. A reversible reaction.
D. All of these
Answer:
A. all of them
Explanation: Edtell
iron filings react with sulphuric acid to produce hydrogen and iron(II) sulphate
Answer:
is this true and false? then its true
Explanation:
Answer:
Fe(s) + H2SO4 (aq) ---> FeSO4 (s) + H2 (g)
Explanation:
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.
What is the solubility of salt at 60°C if 2 gm of the salt is left behind when 7 gm of its saturated solution at that temperature dried?
a) 20
b) 40
c) 60
d) 80
40
Explanation:
because its Saturated
CaCO3 + 2HCl > CaCl2 + CO₂ + H₂O
Explanation:
This reaction is also known as double decomposition reaction.
HCl + CaCO3 + MgCO3 → H2O + H2 + CO2 + CaCl2 + MgCl2
If a pile of a deson of Buttons has a height of 2cm 4mm, what is the thickness of one to button.
The thickness of one button will be 2mm
According to this question, a pile of a dozen buttons has a height of 2cm 4mm. A dozen means 12, hence, 12 buttons has a height of 2cm 4mm.* N.B: We convert the height of the 12 buttons to same unit (mm)
Since 1cm = 10mmThen, 2cm = 2 × 10 = 20mm
20mm + 4mm = 24mm
That is, twelve buttons (a dozen) has a thickness of 24mm, one button will therefore, be:24/12 = 2mm thick
Hence, one button is 2mm thick.
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Oxit bazơ có những tính chất hóa học nào?
Answer:
tác dụng với acid,
Explanation:
You mix the sample discussed in the previous two questions with another sample, which you know to be pure acetylsalicylic acid. You grind the mixture thoroughly with a mortar and pestle, and do a melting point determination on the mixed product. You now observe melting over a range of 127 to 133 C. Now what conclusions can you reach regarding the original product
Answer:
Having high melting point.
Explanation:
The original product has high melting point as compared to the mixture product because in the original product, the element is present in its pure state and we know that pure substances have high melting point as compared to mixture substances due to the presence of strong intercellular forces between them which is hard to break so that's why we can say that the original product has high melting point.
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.
PLZ HELP What is an electron? O A.
A positively charged particle
B. An element on the periodic table
C. A negatively charged particle
D. A particle found in the nucleus SUBMIT
Answer:
C
electrons are negatively charged particles
Answer: D
Explanation:
just took the test
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?
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 %.
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
A pupil has drawn the electronic structure of fluorine and the diagram is shown below. However,
mistakes have been made. State three mistakes that have been made.
The first shell can only hold 2 electrons, but the pupil placed in 8 electrons.
The second shell can hold up to 8 electrons, but the pupil only placed in 2 electrons.
Flourine only has 9 total electrons, yet there are 10 electrons in the diagram.
Answer:
Explanation:
In the Fluorine atom there are 2 electrons in the innermost shell and 7 i the outer shell.
ASAP worth 15 points also
what is the most appropriate unit to measure the following; the length of a football field. b) the diameter of a tennis ball
Explanation:
a) m (metre)
b) mm (millimeter)
please help !!!! may give brainliest
Answer:
Would be increasing the concentration of SO3 as you chose in the question.
Explanation:
Increasing the concentration of the reactant will most likely shift it to the right by adding more products.
Uranium-235 and uranium-238 are different ________ of uranium
(Apx answers please)
Answer:
Isotopes
Explanation:
An isotope are the atoms of an element with similar chemical identity and number of protons but different atomic masses. This means that isotopes of an element differ from one another by their number of NEUTRONS.
For example, the uranium element possesses isotopes as follows: Uranium-235 and uranium-238. This two isotopes have the same chemical identity and number of protons/atomic no., which is 92. However, the atomic masses (235 and 238) are different.
Answer:
Isotopes
Explanation:
Which is the best term to use when describing the energy of motion? chemical kinetic potential thermal
Answer:
Kinetic energy
Explanation:
Kinetic energy is the energy associated with an object's motion. It is mass and velocity dependent by a directly proportional relationship.
Potential energy is the energy associated with an object's position.
Thermal energy is the energy associated with heat addition or withdrawal.
Kinetic energy is the energy that a body possesses because of its movement, that is, it is the energy that arises when objects are in motion.
What is kinetic energy?It is that energy that a body or system possesses due to its movement.The amount of work done by all the forces acting on a body with a given mass, depends on the said mass and the speed of the body.Therefore, we can conclude that kinetic energy is the energy produced by its movements that depends on its mass and speed.
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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
Complete combustion of a 0.350 g sample of a compound in a bomb calorimeter releases 14.0 kJ of heat. The bomb
calorimeter has a mass of 1.20 kg and a specific heat of 3.55 J/(g;°C).
If the initial temperature of the calorimeter is 22.5°C, what is its final temperature?
Use 0= mCOAT
Answer:
i cant understand what you wrote
Explanation:
it's a blank screen
The density of water is 1 g/cm3. Brent used the following method to convert 1 g/cm3 to kg/m3. An equation is shown. The expression on the left has three terms separated by the multiplication sign. The first term is 1 g by 1 cubic cm. The second term is 1 kg by 1000 kg. The third term is 100 cm raised to the power of 3 divided by 1 m raised to the power of 3. The number on the right of the equal to sign is 1000 kg per cubic meter. (1 kg = 1,000 g and 1 m = 100 cm) What is the error in Brent's conversion method?
Answer:
The error includes;
a) The wrong denominator for the equivalent fraction of kilograms to grams
b) The use of the scale factor of length rather than the scale factor of volume for the equivalent fraction of cubic centimeters to cubic meters
c) The arrival at the correct 1000 kg/m³ rather than 0.1 g/m³ based on the expression on the left of the equation
Explanation:
The density of water = 1 g/cm³
The given equation is presented as follows;
1 g/cm³ × 1 kg/(1000 kg) × 100 cm³/(1 m³) = 1000 kg/m³
The error in the conversion method are;
a) The conversion, 1 kg/(1,000 kg) has an error, the correct conversion is (1 kg)/1,000 g)
b) The volume conversion error, 100 cm³/(1 m³), the correct volume conversion is (100 cm)³/(1 m³) = 1,000,000 cm³/(1 m³)
c) The right of the equal to sign error; using the left side expression only, the (wrong) answer is 0.1 g/m³
The correct equation is presented as follows;
1 g/cm³ × 1 kg/(1000 g) × 1,000,000 cm³/(1 m³) = 1000 kg/m³
Answer:
C. 1,000 kg should be written as 1,000 g.
Explanation:
Got it right on my test :)
