Which substance is the least toxic?
a. chlorine (LD50 = 850 mg/kg)
b. vitamin A (LD50 = 2000 mg/kg)
c. cola (LD50 = 140 mg/kg)
d. aspirin (LD50 = 200 mg/kg)
Answer:
I believe it's D. I searched up a lethal table chart and it states Aspirin is even more toxic than chlorine. As for the other two, it didn't specifically state it was toxic with one dose - meaning you have to take more than one dose for toxicity to take effect.
Explanation:
what kind of change is heating of mercuric oxide?
Answer:
Chemical change.
Explanation:
When it is heated it decomposes into mercury and oxygen gas. The mercury oxide reactant becomes the silver color of mercury. Hence, a color change can be noticed throughout the reaction.
Answer:
chemical change
Explanation:
This question is about energy transfers. Which is the correct definition of conduction.'
(1 Point)
Transfer of thermal energy when particles in a heated fluid rise.
Transfer of thermal energy as a wave.
Transfer of thermal energy by the vibration of particles.
how does a drupe fruit differ from a hesperidum fruit.
Answer:
hi
Explanation:
Answer:
Fleshy Fruits: All of most of the ovary wall (pericarp) is soft or fleshy at maturity. ... partitions, juicy seed vesicles, and a leathery exocarp similar to a hesperidium. ... This is a very common dry fruit found in many different plant families.
Explanation:
is mending a broken bone chemical change and why(short answer pls)
Answer:
In a physical change, the substances involved retain their original properties. A new substance is not formed. A physical change can be reversed. Chemical changes happen on a molecular level when two or more substances chemically bond together.
Mending a broken bone is a chemical change as to heal the bone enzymes are released which are chemicals.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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6. A car is driving in a large circle at a constant speed of 20 miles per hour. Is the car accelerating? How do you know?
The car is not accelerating, because the car is driving at a constant speed of 20 miles per hour.
When using pH paper, the pH of a solution can be determined by looking at the _______ of the paper.
What is the molar mass of methane (CHA)?
A. 16.05
grams
O B. 13.02 grams
O C. 49.05 grams
O D. 10 grams
how many grams of NH3 are in 45.9
How many electrons can each individual orbital hold?
Answer:
Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin state. Noble-gas configuration refers to an outer main energy level occupied, in most cases, by eight electrons.
Explanation:
I hope this helps you.
Answer:
Two electrons
Explanation:
Each individual orbital can hold a maximum of two electrons. Hope this helps :)
CO2 + H2O --> C2H2 + O2
Answer:
C2H2 + 5 O2 = 4 CO2 + 2 H2O
Add / Edited: 27.09.2014 / 25.01.2015
Evaluation of information: 5.0 out of 5 / number of votes: 2
Source: https://chemiday.com/en/reaction/3-1-0-339
Explanation:
What does the skeleton do
Explanation:
"The skeletal system works as a support structure for your body. It gives the body its shape, allows movement, makes blood cells, provides protection for organs and stores minerals"
b) Write a few paragraphs describing the chemical reaction and explaining the energy change in the reaction. Your document should: i. identify the reactants and products. ii. describe the change in energy that occurs as bonds are broken and formed. iii. identify how the potential energy of the reactants compares to the potential energy of the products. iv. state and explain the net change in enthalpy. v. identify whether the reaction is endothermic or exothermic. vi. explain how energy is conserved between the reaction and the surrounding environment.
Answer:
The energy change in a chemical reaction is due to the difference in the amounts of stored chemical energy between the products and the reactants. This stored chemical energy, or heat content, of the system is known as its enthalpy.
Explanation:
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Answer:
here is what i put for this project:
The reaction in this project is exothermic. The energy change in a chemical reaction is due to the difference in the amounts of stored chemical energy between the products and the reactants. This stored chemical energy, or heat content, of the system is known as its enthalpy. The potential energy in reactants is higher than the potential energy of products in an exothermic reaction. Since energy is given off, the products are lower in energy than the reactants. The energy that is given off is a result of the formation of new bonds.
The change of the enthalpy happening in the chemical reaction is different from the pathway in between the initial and the final states. The addition of the equation gives the net change of the enthalpy. Enthalpy change is the amount of heat evolved or absorbed in the reaction under constant pressure. This can be calculated by checking the amount of heat evolved during the reaction. This reaction occurs at a constant pressure.
PLS HELP!!! i have no idea what this could be
Answer:
121.5g
Explanation:
from the equation:
2mol of Al react to give 3 mol of Zn
i.e 81g of Al will give 3×81/2 = 243/2 = 121.5g
You are watching the Indy 500 car race on television with your brother. He says, "Did you know that these cars race at a speed of over 200 mph? That velocity is amazing!" Having learned that speed and velocity are not the same, you decide to explain the difference to your brother.
Answer:
See explanation
Explanation:
All physical quantities are broadly classified into scalar quantities and vector quantities.
Scalar quantities have magnitude but do not have direction. Vector quantities have both magnitude and direction. Hence the main difference between a scalar quantity and a vector quantity is that a vector has direction while a scalar quantity does not.
Speed is a scalar quantity while velocity is a vector quantity. You have just specified a magnitude of 200 mph without mentioning its direction. This implies that you are referring to speed of the cars in the race and not velocity because velocity of the cars must indicate the direction!
If I combine atoms then I must be performing which process?
A) Radiation Reaction
B) Strong Force
C) fission
D)Fusion
Answer:
D: fussion
Explanation:
The process called nuclear fussion.
for example, four hydrogen atoms combine in a nuclear fussion reaction to form one helium atom.
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Answer:
the answer to this question here is A
Explanation:
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Answer:
Acid and Salt
Explanation:
Common hydrogen compounds
Hydrogen combines with other elements, forming a number of compounds, including common ones such as water (H2O), ammonia (NH3), methane (CH4), table sugar (C12H22O11), hydrogen peroxide (H2O2) and hydrochloric acid (HCl), according to Jefferson Lab.
Which of these industrial processes typically involves electrolysis?
purifying water for drinking purposes
purifying copper to produce copper wiring for homes
neutralizing an acidic solution by adding a base
neutralizing a basic solution by adding an acid
Answer:
purifying copper to produce copper wiring for homes
Explanation:
Answer:
b.purifying copper to produce copper wiring for homes
Explanation:
BRAINIEST PLS HELPP
Answer:
0.179kg/m3 hope that helps you out
Urgent please help!!!
Describe what you think is your responsibility in taking care of the natural
world in which you live.
Answer:
Well I would say " I think my responsibility is recycling, gardening, picking up litter, and using less pollution. All of this stuff is very important. Sometimes, it's the tiny things that change the world for the better."
I hope this helped! Feel free to add your own little tweaks.
What is the molecular mass for a non-electrolyte if 35.0 g of it is dissolved in 45.0 grams of water and the solutions boiling point is 101.25oC? (The KB for H2O is .51°C/m)
The boiling point of water increases as the amount of impurities dissolved in it increases. For our purposes, we will consider the non-electrolyte to be the dissolved impurity. The change in the boiling point can be calculated using the equation:
[tex]\Delta T_b = i \times K_b \times m[/tex]
where [tex]\Delta T_b[/tex] is the change in boiling point, [tex]i[/tex] is the van ‘t Hoff factor (whose value denotes the number of particles each formula unit of the dissolved substance dissociates into in water), [tex]K_b[/tex] is the boiling point elevation constant, and [tex]m[/tex] is the molality (moles of solute/kilogram of solvent) of the solution.
Right off the bat, since we're dealing with a non-electrolyte, the dissolved substance can be assumed not to dissociate in water. So, our van ‘t Hoff factor, [tex]i[/tex], would be 1 (by contrast, the [tex]i[/tex] for an ionic compound like NaCl would be 2 since, in water, NaCl would dissociate into two particles: one Na⁺ ion and one Cl⁻ ion). We're also given our [tex]K_b[/tex], which is 0.51 °C/m.
Assuming the normal boiling point of pure water to be 100 °C (a defined value for sig fig purposes), the change in boiling point from having dissolved 35.0 g of the non-electrolyte can be obtained by subtracting 100 °C from the final—elevated—boiling point of 101.25 °C:
[tex]\Delta T_b = 101.25\text{ }^o\text{C} - 100\text{ }^o\text{C} = 1.25\text{ }^o\text{C}[/tex]
Now, recall what we're asked to determine: the molecular mass of the dissolved substance. There is one unknown left in the equation: the molality of the solution. Let's first solve for that:
[tex]m = \frac{\Delta T_b}{K_b} = \frac{1.25^\text{ o}\text{C}}{0.51^\text{ o}\text{C}/m} \\ m = 2.45 \text{ mol solute/kg water}.[/tex]
Notice that we didn't include the i since its value is 1.
Now, what would happen if we multiplied our molality by the mass of water we've been given? We would be left with the moles of solute. And what are we asked to find? The molecular mass, or the mass per mole. We can accomplish this in two steps. Remember to convert your mass of water to kilograms:
[tex]2.45 \text{ mol solute/kg water} \times 0.045 \text{ kg water} = 0.110 \text{ mol solute.}[/tex]
And, finally, we divide the mass of our solute by the number of moles of solute:
[tex]\frac{35.0 \text{ g solute}}{0.110 \text{ mol solute}} = 317.5 \text{ g/mol}[/tex]
Our answer to two significant figures (which is the number of sig figs to which our [tex]K_b[/tex] is given) would be 320 g/mol.
2H20 → 2H2 + O2
Type of reaction?
Answer:
Notice how the elements splitIt is a decomposition reaction I do exams and quizzes if ur interestedNEED HELP ASAP!!!
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How does a material get a negative charge?
Explanation:
When insulating materials rub against each other, they may become electrically charged . Electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. The material that gains electrons becomes negatively charged. The material that loses electrons is left with a positive charge.
What is the purpose of the stairstep pattern on the periodic table of the elements?
Answer: The bold staircase in the periodic table allows us to classify which elements are metalloids.
Explanation: Additionally, it acts like a "divider" that allows us to properly distinguish the metals from the non-metals in the periodic table.
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Which processes occur when energy is removed from a substance
Answer:
Note that melting and vaporization are endothermic processes in that they absorb or require energy, while freezing and condensation are exothermic process as they release energy.
In the tropical rainforests, birds have evolved to eat the brightly-colored fruits. The fruits have evolved their attractive color so the birds will eat them and spread their seed. What theory is this an example of? A artificial selection b coevolution c mutation d natural selection
Answer:
coevolution
Explanation:
Coevolution plays a key role in shaping the biodiversity on Earth. Coevolution is commonly defined as reciprocal evolutionary changes brought about by interactions between species, implying that interacting species impose selection on each other(Science direct).
We can see that the change that occurred in the plants of the tropical rainforests is closely related to their link to birds. The fruits evolved an attractive color so that birds, having evolved to eat the brightly-colored fruits, may eat them.
Match the special cases of each gas law with its description. A law may be used more than once. In the equations, K is a constant.
A. Boyle's law
B. Charles's law
C. Avogadro's law
D. Dalton's law
____ P1 V1 = P2 V2
____ V/T = k
____ V1 / T1 = V2 / T2
____ V = kn
____ PV = k
____ Ptotal = P1 + P2 + P3 + .
The special cases of gas laws and its description includes:
A. Boyle's law: P1 V1 = P2 V2
B. Charles's law: V/T = k or V1 / T1 = V2 / T2
C. Avogadro's law: V = kn
D. Dalton's law: Ptotal = P1 + P2 + P3 + .
What is gas law?Gas laws are laws that relate a gas's pressure, volume, and temperature. Boyle's law, named after Robert Boyle, states that the pressure P of a gas varies inversely with its volume V at constant temperature, or PV = k, where k is a constant. Charles' law is named after J. -A. -C.
They also include; Gay-Lussac's Law, Avogadro's Law and Dalton's law of partial pressures.
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what is hybridization
Answer:
Hybridization is the concept of mixing atomic orbitals into new hybrid orbitals suitable for the pairing of electrons to form chemical bonds in valance bond theory.
Suppose you were to make 36 grilled cheese sandwiches, how many pieces of bread do you need? show your work