Questions posted in Chemistry - AssignmentGrade.com

Questions posted in Chemistry

A scientist should not let their research and study be influenced by _____. (can be more than one answer) ethnicity gender nationality religion

A scientist should never let their research and experimental study be influenced by ethnicity, gender, nationality, religion or any other external factor. Any external influence such as these may lead to bias in the experimental results and yield a conclusion that is incorrect. In general, experiments should be designed in such a way that eliminates such bias. 

ANSWERED AT 26/05/2020 - 01:22 PM


QUESTION POSTED AT 26/05/2020 - 01:22 PM

What volume of a 2.5 M stock solution of H3PO4 is needed to prepare 3.8 L of a 1.5 M H3PO4 solution?

Given:
Let M be the molarity of the solution
Let V be the volume of the solution

M_1 = 2.5 M
M_2 = 1.5 M
V_2 = 3.8 L

Required:
 V_1 = ?

Solution:

M_1 x V_1 = M_2 x V_2
Substitute all known values
V_1 = (1.5 M x 3.8 L)/2.5 M
∴ V_1 = 2.28 L

Interpretation:
 To prepare 3.8 L of 1.5 M H3PO4 solution you need 2.28 L of 2.5 M stock solution of H3PO4.

ANSWERED AT 26/05/2020 - 01:20 PM


QUESTION POSTED AT 26/05/2020 - 01:20 PM

If you cut the ice cube in half, what do you think would happen when it is placed in the alcohol? Please explain your answer.

When an ice cube is cut in half, the surface area increases. This causes an increased speed of physical change (melting in this case) by the ice. 

ANSWERED AT 26/05/2020 - 01:17 PM


QUESTION POSTED AT 26/05/2020 - 01:17 PM

A (what) forms when the sperm first fertilizes an egg

Fertilization occurs when the nucleus of both a sperm and egg fuse to form a diploid cell known as zygote the successful fusion of gametes forms a new organization

ANSWERED AT 26/05/2020 - 01:16 PM


QUESTION POSTED AT 26/05/2020 - 01:16 PM

The picture shows a great deal of cocoa mix on the surface. Suppose that no more cocoa can be dissolved. The solution has reached

The answer to this is saturation. When a solvent cannot dissolve any more solute, the substance has reached saturation and is saturated. However, there is also supersaturation when a solute can be dissolved in a solvent beyond saturation by altering the heat and physically changing the solution, then later reversing it. 

ANSWERED AT 26/05/2020 - 01:15 PM


QUESTION POSTED AT 26/05/2020 - 01:15 PM

Why don't rockets need air to stay up, like planes do?

Part of a rocket's propulsion system includes a chemical oxidizer, either in the form of liquid oxygen, the solid ammonium perchlorate, or the propulsion/oxidizer mixture Hydrazine. No outside source of oxygen is needed. 

Steering is accomplished by "gimbaled" rocket nozzles which change the direction of the blast to keep the rocket on course. Once in space and in orbit, slight changes in orientation is made by small rockets placed around the craft that spurt little gas jets to nudge the craft into the desired position.

ANSWERED AT 26/05/2020 - 01:15 PM


QUESTION POSTED AT 26/05/2020 - 01:15 PM

When the temperature of the air is 50°C, the velocity of a sound wave traveling through the air is approximately

In this item, we are to calculate for the speed or velocity of sound in air with a temperature of 50°C. The dependence of the velocity of sound in temperature is expressed in the following equation:
                        v = 331 m/s + (0.6 m/s°C)(T)
where v is the velocity and T is temperature. 

Substituting the known values from the given,
                        v = 331 + (0.6)(50) = 361 m/s

Thus, the velocity of sound in air at 50°C is approximately 361 m/s. 

ANSWERED AT 26/05/2020 - 01:14 PM


QUESTION POSTED AT 26/05/2020 - 01:14 PM

In order for a liquid particle to become a gas it must: (choose all that apply) overcome the attractive forces of other liquid particles overcome the attractive forces of other gas particles gain energy lose energy

It must be heated in order for the liquid to start heating up or boiling and as it is, Water vapor will start to rise, and now the liquid has turned into gas by heating.

ANSWERED AT 26/05/2020 - 01:12 PM


QUESTION POSTED AT 26/05/2020 - 01:12 PM

Nonmetallic elements form ions by _____ valence electrons to complete their outer shell.

Answer: Non-metals form ions when they gain electrons.

Explanation:

An ion is formed when an atom looses or gains electron.

  • When an atom looses electrons, it will form a positive ion known as cation.
  • When an atom gains electrons, it will form a negative ion known as anion.

Metals are the elements which have a tendency to loose electrons and thus they form cations. Example: Sodium will loose 1 electron to form Na^+ ion.

Non-metals are the elements which have a tendency to gain electrons and thus they form anions. Example: Fluorine will gain 1 electron to form F^- ion.

Hence, non-metals form ions when they gain electrons.

ANSWERED AT 26/05/2020 - 01:12 PM


QUESTION POSTED AT 26/05/2020 - 01:12 PM

What are 3 adaptations that help humans have differential survivability

1. Lactose tolerance in adulthood. Lets an adult drink cow milk without getting gassy or feeling sick. Cow milk has all sorts of good stuff in it and probably drinking it can help a woman support a pregnancy. 

2. Sickle cell anemia allele. The heterozygotes don't die of malaria or sickle cell anemia. This is a "heterozygote advantage" in parts of the world where mosquitoes carry malaria. 

3. Straight black hair. Sexual selection decoration (historical). People in parts of Asia who had blond or white hair could never get married -- they were discriminated agains

ANSWERED AT 26/05/2020 - 01:12 PM


QUESTION POSTED AT 26/05/2020 - 01:12 PM

Prefix meaning 1/1000

Ignore this because i just need to verify my account

ANSWERED AT 26/05/2020 - 01:12 PM


QUESTION POSTED AT 26/05/2020 - 01:12 PM

Which best explains what happens when an electron moves from an excited state to the ground state? The electron absorbs energy as it moves to a lower energy level. The electron absorbs energy as it moves to a higher energy level. The electron releases energy as it moves to a higher energy level. The electron releases energy as it moves to a lower energy level.

I believe the correct answer would be the last option. When an electrons moves from an excited state to the ground state, it would release energy. An electron in the excited state would mean that it contains high kinetic energy so to move to a lower state some of these energy should be released.

ANSWERED AT 26/05/2020 - 01:10 PM


QUESTION POSTED AT 26/05/2020 - 01:10 PM

Which is the formula for diarsenic pentoxide?

Formula for diarsenic pentoxide
As2O5

ANSWERED AT 26/05/2020 - 01:10 PM


QUESTION POSTED AT 26/05/2020 - 01:10 PM

Which of the following describes the Bohr atomic model?

In Bohr's atomic model, an atom consist of a nucleus that is positively charged and is being surrounded by electrons that are said to travel in orbits or circular manner around. It is compared to the solar system where the nucleus is equivalent to the sun and the electrons are the planets.

ANSWERED AT 26/05/2020 - 01:09 PM


QUESTION POSTED AT 26/05/2020 - 01:09 PM

Potassium fluoride (KF, a salt, has a molecular weight of 58.10 grams. How many grams would be needed to make 1.0 liter of 5.0 molar salt solution?

The concentration of the solution is 5.0 molar, which is 5.0 mole/L.  So in the 1.0 L of 5.0 molar KF salt solution, the moles of KF is 5.0molar*1.0L=5.0 mole. The molecular weight of KF is given in the question as 58.10 gram/mole, so the grams of KF is 58.10 gram/mole * 5.0 mole = 290.5 gram.

ANSWERED AT 26/05/2020 - 01:05 PM


QUESTION POSTED AT 26/05/2020 - 01:05 PM

Two atoms have the same number of protons but different number of neutrons. what can you conclude about these masses

These masses are isotopes. By definition, isotopes of an element have the same number of protons as the given element, but different numbers of neutrons.

ANSWERED AT 26/05/2020 - 01:01 PM


QUESTION POSTED AT 26/05/2020 - 01:01 PM

Vancouver, British Columbia, enjoys a moderate year-round climate due to

Answer:

Vancouver, British Columbia, enjoys a moderate year-round climate due to its proximity to the Pacific Ocean.

Explanation:

Vancouver has an oceanic climate and has, in winter, the second highest average temperature in the country, just behind Victoria. Its summer, however, is one of the mildest in the country. Winters not too cold and summers not very hot are mainly due to the fact that the city is located on the coast. While in other Canadian cities, such as Toronto, Montreal and Ottawa, temperatures can reach -20 ° C in winter and 35 ° C in summer, Vancouver rarely reaches -10 ° C in winter and 30 ° C in summer.

ANSWERED AT 26/05/2020 - 12:58 PM


QUESTION POSTED AT 26/05/2020 - 12:58 PM

A scientist conducts a chemical reaction. At the beginning of the reaction, she combines 5.4 grams of the first reactant and 6.3 grams of the second reactant. She runs the reaction in a closed chamber and heats only the reaction. A small amount of gas is produced. What can you conclude about the total mass of the substances present when the reaction is complete?

The total of the mass of the substances present should be approximately equal to the sum of the mass of the reactants or 11.7 g assuming that the mas of the gas produced is negligible or very small. This is to agree the law of conservation of mass where mass cannot be created nor destroyed.

ANSWERED AT 26/05/2020 - 12:58 PM


QUESTION POSTED AT 26/05/2020 - 12:58 PM

What lightens stains better vinegar or lemon juice also what is the hypothesis for it

Lemon juice because it releases carbon dioxide

ANSWERED AT 26/05/2020 - 12:57 PM


QUESTION POSTED AT 26/05/2020 - 12:57 PM

Complete the balancing of the equation for the roasting of stibnite, using smallest whole-number coefficients. Sb2S3+O2 yields Sb2O3+SO2. Please explain because I don't understand this specific question

The answer is 2Sb2S3 + 902 yields 2Sb2O3 + 6SO2

And the question os just asking you to find the simplest for of balancing for this equation

ANSWERED AT 26/05/2020 - 12:46 PM


QUESTION POSTED AT 26/05/2020 - 12:46 PM

What is the element sulfur classified as

Sulfur is classified as a metal

ANSWERED AT 26/05/2020 - 12:44 PM


QUESTION POSTED AT 26/05/2020 - 12:44 PM

Meteorologists, with the help of weather station data and computers, use many weather tools to help forecast the weather, such as _____.

psychrometers,barometers, radiosondes and Doppler radars.

ANSWERED AT 26/05/2020 - 12:43 PM


QUESTION POSTED AT 26/05/2020 - 12:43 PM

Which statement best describes the compressibility of a gas? Increasing the temperature of a gas decreases the pressure. Increasing the temperature of a gas increases the pressure. Increasing the pressure on a gas decreases the volume. Increasing the pressure on a gas increases the volume.

The correct answer is option C. i.e. Increasing the pressure on a gas decreases the volume.
The gas can be compressed by increasing the pressure on the gas and taking account of the changes in volume that place on increasing or decreasing the pressure.
This is verified from the gas equation, PV = nRT
As, you increase the pressure, the volume will decrease.

ANSWERED AT 26/05/2020 - 12:42 PM


QUESTION POSTED AT 26/05/2020 - 12:42 PM

Which of the following correctly explains the steps pictured below? a Prophase II, Metaphase II, Anaphase II b Prophase II, Anaphase II, Telophase II c Prophase I, Prophase II, Metaphase I d Prophase I, Metaphase I, Anaphase I

Its kinda hard to tell but it looks like A because you can see the chromosome appears to be dividing at the centromere in the bottom illustration which is Anaphase II

ANSWERED AT 26/05/2020 - 12:41 PM


QUESTION POSTED AT 26/05/2020 - 12:41 PM

Which element in the image will turn into extrusive igneous rock?

Magma, if it's the picture I know of then it would be "C"

ANSWERED AT 26/05/2020 - 12:40 PM


QUESTION POSTED AT 26/05/2020 - 12:40 PM

Which trait would most likely lead a scientist to investigate a blood-thinning agent in the saliva of vampire bats? A) creativity B) curiosity C) diversity D) skepticism

Most likely D. skepticism, but it could also be B. curiosity. Not a very good question :/

ANSWERED AT 26/05/2020 - 12:39 PM


QUESTION POSTED AT 26/05/2020 - 12:39 PM