Answer:
The actinides and the lanthanides
The half-life of Palladium-100 is 4 days. After 16 days a sample of Palladium-100 has been reduced to a mass of 6 mg. What was the initial mass (in mg) of the sample
Answer:
96mg
Explanation:
Since the half-life of Palladium-100 is 4 days and the sample has been reduced after 16 days, that means the sample has undergone four half-lives. To find the intial mass, just work backwards:
6 x 2= 1212 x 2= 2424 x 2= 48 48 x 2= 96As you see, I've worked backwards from the four half-lives. So the initial mass after 16 days is 96 mg.
(b)
Analysis of a molecule of DNA showed that cytosine accounted for 42 per cent of the
content of the nitrogenous bases. Calculate the percentage of bases in the molecule
which would be thymine. Show your working.
8%
Explanation:
In a DNA molecule the no. of Adenine bases equal to that of Thymine bases
The no. of Cytosine bases equal to that of Guamine bases.
If we take no. of Thymine bases as x and no. of Cytosine bases as y,
Adenine + Thymine + Cytosine + Guamine = 100
x + x + y+y = 100
2( x+y) = 100
x+y = 50
y=42
therefore x= 50-42 = 8%
A compound contains 36.48% Na, 25.41% S, and 38.11% O. Find it’s empirical formula
Answer:
we can use 100g of compounds as the basis.
Explanation:
How could the student obtain zinc chloride solution from the reaction mixture when all the hydrochloric acid has reacted?
Answer:
zinc oxide is only sparingly soluble in water so best option is to add zinc oxide to diluted hydrocrolic acid
When all the hydrochloric acid (HCl) has reacted, the student can obtain zinc chloride (ZnCl) solution from the reaction mixture by adding ZnO to diluted HCl.
What is a mixture?
A mixture simply refers to a combination of two (2) or more substances or chemical compounds that are present in varied proportion, and they can be visibly seen with na-ked eyes.
In this scenario, the student can obtain zinc chloride (ZnCl) solution from the reaction mixture when all the hydrochloric acid (HCl) has reacted by adding zinc oxide (ZnO) to diluted hydrochloric acid (HCl) because it's sparingly soluble in water.
Read more on mixture here: https://brainly.com/question/24647756
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What would happen if we didn’t have the Milky Way
Mention the type of
Reaction common
to organic compound-
Answer:
addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, photochemical reactions and redox reactions
Monica put four items on the desk that you need to measure the mass of. The items are listed below. Which of the following would need to be put in a container in order to measure the mass on a scale?
I. Flour
II. Sugar cubes
III. Milk
IV. An unbroken egg
A. I and III
B. I and IV
C. II and III
D. III and IV
Answer:
it D because it make more sense
what is the best way to study and understand electron configuration??
Answer:
You have to remember this memory aid, diagonals and all.
You have to keep a tight tally of the electrons you’ve used so far so you don’t go over the number of electrons in the element you’re working on.
You have to remember how many electrons fit into each subshell (s, p, d, f).
It takes a lot of time, especially when the element has more than 20 electrons.
Explanation:
Question ( please help me )
1 . Which diagram shows pure substance that are elements
2. Which diagram shows pure substance are compounds
3. Which diagram shows a mixture of compounds
4. Which diagram shows a mixture of elements
5. Which diagram shows a mixture of an element and a compound
Answer:
1. F, H, E
2. A, D, I
3. G
4. E, B, H
5. C
Explanation:
can I get some help.and no link I have the table already I just need the information. it's graded please
Answer:
You did very well and its correct.
Explanation:
Great Job!
Which factor most often affects wind and weather patterns on Earth?
Answer:
i think its solar radiation
What do the carbon, oxygen, and nitrogen cycles all have in common? a. They all include an exchange of gases with the atmosphere. b. None of the cycles are biogeochemical cycles. c. They are all byproducts of photosynthesis. d. They all sustain life, but living organisms have no part in the cycle. Please select the best answer from the choices provided A B C D
How to calculate work done with change in volume and pressure.
[tex]W = \displaystyle \int dW = \displaystyle \int^{V_2}_{V_1} p ~dV = p(V_2 - V_1) = p \Delta V[/tex]
Which statement describes the motion of the ice particles in the ice/water bath between minutes 5 and 20?
Choose the correct answer.
Particle motion stays the same because temperature does not change.
Particle motion stays the same because the ice is not completely melted yet.
Particle motion increases because thermal energy is being transferred to the ice.
Particle motion decreases because thermal energy is being transferred away from the ice.
Explanation:
The ice cube which was solid has turned into the liquid water because the air temperature is warmer than the freezers. Which means the ice particles gather heat energy from the warmer air. Therefore the ice particles have enough energy to break apart (melt)into smaller particle arrangements.
What is required for two atoms to share electrons equally in a chemical bend?
Answer: Nonpolar Covalent Bond
Explanation: A Nonpolar Covalent Bond is created when atoms share their electrons equally. This usually occurs when two atoms have similar or the same electron affinity. The closer the values of their electron affinity, the stronger the attraction. This occurs in gas molecules; also known as diatomic elements.
Vanadium crystallizes in a body-centered cubic lattice, and the length of the edge of a unit cell is 305 pm. What is the density of V
Answer:
5.96 g/cm^3
Explanation:
Corner atom = 1/8
Atoms in center = 1
Atoms in face of the cube= 1/2
Molar mass of V = 50.94 g/mol (from period table)
1 mole = 6.02x10^23
In BCC unit cell:
(8 x 1/8)+ 1=2 per 1 unit cell
Mass: 2(50.94g)/6.02x10^23 = 1.69x10^-22 g/unit cell
305pm=(305x10^-12m÷10^-2m) x (1mL÷1cm^3)
= 2.837 x 10^-23 mL
1pm=10^-12m
1cm=10^-2m
1mL=1cm^3
density=mass/volume
density of V = 1.69x10^-22g÷2.837x10^-23mL
=5.957g/mL
=5.96g/cm^3
Based on properties of elements in the periodic table, which element is the best conductor of thermal energy?.
Answer:
Silver
Explanation:
Silver has the highest thermal conductivity of any element and the highest light reflectance.
Apply: Many gyms and health clubs have steam saunas, which are small steam-filled rooms. Traditionally, steam saunas have a container of heated rocks. A small ladle of water is poured on the rocks in order to make the steam.
1. Use what you have learned so far about heat transfer to explain how hot rocks can be used to make steam?
2. Why do you think only a small ladle-full of water is poured on the rocks at one time?
Answer:
the heat vaporization of water is very high with small amounts of water you can vaporize the water as it hits the rocks into steam. (i think)
Explanation:
Can elements from group 1 and 2 show up as pure elements in nature? Except Hydrogen
Answer:
No. Although alkali metals and alkaline earth metals are found in nature, they are not found as pure elements. Group 1 and 2 are found in their chemical compounds, not pure form.
how many moles are equal to 2.25 moles of sulfur dioxide
Answer:
6.02 x 10^23 (6.02 times 10 to the power of 23)
a
A sample of gas has a volume of 3.50 L and a pressure of
125 mm Hg. What will the new pressure be when the volume
is decreased to 2.75 L? The temperature stays the same.
Answer:
159.09 mmHgExplanation:
The new pressure can be found by using the formula for Boyle's law which is
[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]
where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
From the question we have
[tex]P_2 = \frac{125\times3.50 }{2.75} = \frac{437.5}{2.75} \\ = 159.090909...[/tex]
We have the final answer as
159.09 mmHgHope this helps you
What is the formula for the ionic compound formed by calcium and selenium?
Answer:
CaSe
Explanation:
not sure!!
Question 7 (1 point)
Which of the following organelles helps organisms maintain homeostasis by controlling what substances may enter or leave cells?
Answer:
Cell membranes (plasma membranes) help organisms maintain homeostasis by controlling what substances may enter or leave cells.
20. Which of the following elements would you expect to lose one electron? Select all that apply.
.
Fluorine
Potassium
Chlorine
Sodium
Answer:
Sodium and Potassium only
describe how modeling is useful in studying the structure of the atom.
Answer:
Scientists use models to study atoms because atoms are extremely small and can't even be seen. If atoms can't be seen, it's easier to study and.
Explanation:
hope it helps you
how long does vacuum sealed raw meat last in the freezer?
Answer:
Frozen Meats – Frozen raw meats that are properly vacuum sealed can be stored in the freezer from 1-3 years depending on the type of meat. However, raw meat that is not vacuum sealed will only last 1-12 months depending on the meat.
Explanation:
hop this helps
Answer: Six months or three years
Explanation: Frozen meats, poultry, and fish can last in the freezer for up to six months and when they are vacuum sealed, frozen meats can stay fresh and free from freezer burn for up to 3 years.
Cryolite is an ore of aluminium used in the extraction of aluminium from bauxite;
it was found to have 33% sodium, 13% aluminium and 54% fluorine.
Work out the empirical formula.
g. What is crystallization?Name any two go mixtures that can be separated by this method:name any two mixtures that can be separated by
crystallization is a process which helps to separate a pure solid from a solution in its crystal form. This is the in use to purify solid. For an example the salt we get from seawater can have many impurities in it. Hence, the process of crystallization is in use to remove these impurities.
Sugar and salt are examples of products where crystallization does not only serve as separation/purification technique, but where it is also responsible for getting crystals with the right size (and shape) for further application of the products.
- BRAINLIEST answerer
Answer:
Crystallization is the process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some of the ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.
Sugar and salt are two mixtures that can be seperated by crystallization
Explanation:
I do believe i need help.....
Answer:
C,D, and A I believe
Explanation:
Drag the names to the order planets based their distance from the sun, beginning with the planet closet to the sun.
Answer: In this order
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Explanation:
Answer:
Mars.....................