Explain why a sewing needle can float on the surface of water in a glass

QUESTION POSTED AT 12/02/2020 - 04:49 PM

Answered by admin AT 12/02/2020 - 04:49 PM

I guess it's because it's less dense than the water?
Post your answer

Related questions

The force of gravity on the surface of a planet will affect a person's or object's _

It would affect the person or object's weight. I hope this helped! It would affect the person or object's weight. I hope this helped! This is because of the mass and force of gravity involved. 

ANSWERED AT 28/02/2020 - 05:23 PM


QUESTION POSTED AT 28/02/2020 - 05:23 PM

According to recent research, ice skaters are able to glide smoothly across the ice because A. ice is constantly subliming to form a layer of water vapor B. a thin, liquid-like layer of water covers the ice C. pressure from the skates raises the melting point of ice D. pressure from the skates lowers the melting point of ice

Answer:

B. A thin, liquid-like layer of water covers the ice

Explanation:

Hello,

Ice skaters are able to glide smoothly across the ice because a thin, liquid-like layer of water covers the ice, this is achieved due to the environmental conditions which allow the liquid water layer to coexist with the ice. Due to this fact, the liquid-like layer diminishes the friction coefficient between the ice skateboard and the ice allowing the slip to be carried out smoothly.

Best regards.

ANSWERED AT 28/02/2020 - 05:05 PM


QUESTION POSTED AT 28/02/2020 - 05:05 PM

Which piece of equipment would be most useful for measuring the volume of some water?

A graduated cylinder. :)

ANSWERED AT 28/02/2020 - 05:00 PM


QUESTION POSTED AT 28/02/2020 - 05:00 PM

Acid mine drainage is formed when water flows past exposed rocks that leach out ______________________ that react with water and oxygen to form

Acid mine drainage is formed when water flows past exposed rocks that leaches out sulfates that react with water and oxygen to form. Sulfate is the answer which means that a salt or it is sulfuric acid. This polyatomic anion is part of our everyday life.

ANSWERED AT 28/02/2020 - 04:42 PM


QUESTION POSTED AT 28/02/2020 - 04:42 PM

What happens to the temperature of water between the time ice melts and water boils (this is partially quoted from a question)? Also, what change occurs in temperature after water starts boiling (this is also from a booklet)? Thank you and please explain your thoughts. This is based on the phase changes of water, and you should refer to a graph on the phase changes of water.

Your first statement is very ambiguous so I will give it the best shot as to what you are saying.
The temperature, between the point of ice melting and water boiling, is increasing as water is in its liquid state.
Now during a phase change, or while the water is boiling, the temperature remains constant because the energy being added is being consumed to complete the phase change.
But if you're looking at the phase change graph, the points of positive slopes, are moments when energy is increasing as the water, in whatever state, is increasing. But when the slope of the graph is 0, the water is changing phases and the temperature remains constant! I hope I explained that so you could understand it, and I hope this helps you!

ANSWERED AT 28/02/2020 - 03:47 PM


QUESTION POSTED AT 28/02/2020 - 03:47 PM

What kind of instrument is this and explain the details what it measures

I believe it measures the pressure in the atmosphere. Not positive on the name...barometric pressure gauge? 

ANSWERED AT 28/02/2020 - 03:27 PM


QUESTION POSTED AT 28/02/2020 - 03:27 PM

Which of the following is not one of the three ingredients needed to form a cloud? dust or solid matter of some sort water molecules wind temperature and pressure changes

I think is wind(not needed in the formation of cloud).

ANSWERED AT 28/02/2020 - 02:57 PM


QUESTION POSTED AT 28/02/2020 - 02:57 PM

Explain why neptune cannot be seen without a telescope

Because it's to little

ANSWERED AT 28/02/2020 - 02:50 PM


QUESTION POSTED AT 28/02/2020 - 02:50 PM

What is process of bringing water to boiling affects

Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere. There are two main types of boiling; nucleate boiling where small bubbles of vapour form at discrete points, and critical heat flux boiling where the boiling surface is heated above a certain critical temperature and a film of vapor forms on the surface. Transition boiling is an intermediate, unstable form of boiling with elements of both types. The boiling point of water is 100 °C or 212 °F, but is lower with the decreased atmospheric pressure found at higher altitudes.

Boiling water is used as a method of making it potable by killing microbes that may be present. The sensitivity of different micro-organisms to heat varies, but if water is held at 70 °C (158 °F) for ten minutes, many organisms are killed, but some are more resistant to heat and require one minute at the boiling point of water. Clostridium spores can survive this treatment, but as the infection caused by this microbe is not water-borne, this is not a problem.

Boiling is also used in cooking. Foods suitable for boiling include vegetables, starchy foods such as rice, noodles and potatoes, eggs, meats, sauces, stocks and soups. As a cooking method it is simple and suitable for large scale cookery. Tough meats or poultry can be given a long, slow cooking and a nutritious stock is produced. Disadvantages include loss of water-soluble vitamins and minerals. Commercially prepared foodstuffs are sometimes packed in polythene sachets and sold as "boil-in-the-bag" products.


ANSWERED AT 28/02/2020 - 02:15 PM


QUESTION POSTED AT 28/02/2020 - 02:15 PM

Earth has several ideal features which enable it to support life. MOST important is the A) gravitational force on Earth. B) existence of tectonic plates. C) relationship between Earth and its moon. D) existence and amount of water on Earth's surface.

Earth Has Several Ideal Features which enable it to support Life. (MOST) Important is the

Answer:D.) Existence and amount of water on Earth's Surface.

Explaining:All of the Answer's choices help Earth, in some way, to Support life.But Most important is the Existence and amount of the water on earth surface             
                                          Good Luck...... *-*



ANSWERED AT 28/02/2020 - 01:14 PM


QUESTION POSTED AT 28/02/2020 - 01:14 PM

Is ethanol hydrophilic or hydrophobic? Explain.

The other end contains an -OH group that can form hydrogen bonds to neighboring water molecules and is therefore said to be hydrophilic (literally, "water-loving"). ... One end of this alcohol molecule is nonpolar, and therefore hydrophobic. The other end is polar, and therefore hydrophilic.
Copy and paste this for more information: 
chemed.chem.purdue.edu/genchem/topicreview/bp/ch15/solut.php

ANSWERED AT 28/02/2020 - 12:51 PM


QUESTION POSTED AT 28/02/2020 - 12:51 PM

The molar mass of water (H2O) is 18.0 g/mol. A sample of water has a mass of 18.0 g. How many moles of water are contained in this sample? a) 1.00 b) 18.0 c) 36.0 d) 324

Number of moles = Given Mass / Molar mass

Here, Given mass = 18 g
Molar mass = 18 g/mol

Substitute their values, 
n = 18/18
n = 1 mol

In short, Your Answer would be: Option A

Hope this helps!

ANSWERED AT 28/02/2020 - 12:46 PM


QUESTION POSTED AT 28/02/2020 - 12:46 PM

All of the following statements about the atmosphere are true except: A. The biosphere includes all living organisms on Earth's surface. B.Like ''biology'' the name for the biosphere comes from the Greek world for life. c. Light and heat from the sun don't affect the biosphere. D.The biosphere gets resources from Earth's crust, hydrosphere and atmophere

Answer: c. Light and heat from the sun don't affect the biosphere.

Explanation:

The biosphere is the sphere where living beings such as plants, animals, microbes, humans and others survive, reproduce and lead their life cycle.  

The atmosphere is a sphere of the earth. It consists of collection of different gas called as air. It protects the biosphere by absorbing the incident harmful radiations along with heat coming from the sun.

ANSWERED AT 28/02/2020 - 12:37 PM


QUESTION POSTED AT 28/02/2020 - 12:37 PM

How does phosphorous reach surface waters ?

It is an essential element for plant life, but when there is too much of it in water, itcan speed up eutrophication (a reduction in dissolved oxygen in water bodies caused by an increase of mineral and organic nutrients) of rivers and lakes. Soil erosion is a major contributor of phosphorus to streams.

Here is a website link for you if you don't understand. https://water.usgs.gov/edu/phosphorus.html
Here's a video if you're still having trouble http://study.com/academy/lesson/what-is-eutrophication-definition-causes-effects.html

ANSWERED AT 28/02/2020 - 12:06 PM


QUESTION POSTED AT 28/02/2020 - 12:06 PM

What is the difference between a mixture and a compound? (need an easy two sentence answer (able to explain it to a 8 your old).)

 A mixture is made from two or more substances that are chemically unlike and are not chemically joined. A compound is a substance formed when two or more elements chemically react with each other to ... substances because no new substance is formed, therefore they do not have any fixed properties.

ANSWERED AT 28/02/2020 - 12:02 PM


QUESTION POSTED AT 28/02/2020 - 12:02 PM

Explain the process of separating a mixture consisting of iron fillings and sand in a plastic bowl.

Answer: To separate the iron sand mixture we will use a magnet to get rid of the iron filings from the sand as a result of sand isn't drawn to the magnet. once separation, the elements of the mixture can have the identical composition and properties as they didn't begin with. Hence , magnet can be used for seprating a mixture of iron fillings and sand .

ANSWERED AT 28/02/2020 - 11:51 AM


QUESTION POSTED AT 28/02/2020 - 11:51 AM

Which of the following is a chemical change? A. melting ice B. boiling water C. burning candle D. frost forming inside of a freezer

Answer to this question is c. burning candle. the rest of the choices are phase changes

ANSWERED AT 28/02/2020 - 11:44 AM


QUESTION POSTED AT 28/02/2020 - 11:44 AM

Luis set a glass of water outside in the sunshine. when he looked at the glass ten minutes later, the contents had changed. what king of change happened to the ice water?

Physical change because  the ice is still tecnecly water

ANSWERED AT 28/02/2020 - 11:40 AM


QUESTION POSTED AT 28/02/2020 - 11:40 AM

A sample of water is mixed with a surfactant. What will most likely happen to the viscosity of the water? Explain your answer.

--The viscosity of the water will decrease.

--Surfactants disrupt intermolecular forces within a liquid.

--Viscosity is directly related to intermolecular forces.

--If intermolecular forces are decreased, viscosity should also decrease.

ANSWERED AT 28/02/2020 - 11:23 AM


QUESTION POSTED AT 28/02/2020 - 11:23 AM

The forces between water molecules are stronger than the forces between ethanol molecules. Which liquid would probably be most difficult for an insect to walk on? Explain your answer.

An insect would have an easier time walking on the surface of water than on the surface of ethanol. Water's stronger intermolecular forces lead to higher surface tension. Higher surface tension allows water to support the insect. I hope this helps.

ANSWERED AT 28/02/2020 - 11:20 AM


QUESTION POSTED AT 28/02/2020 - 11:20 AM

The elements which make up water can only be separated by chemical means. That means water is __________. a. a mixture b. an element c. a solution d. a compound

Water is a compound because it is made up of two elements.

ANSWERED AT 28/02/2020 - 11:20 AM


QUESTION POSTED AT 28/02/2020 - 11:20 AM

A sample of nitrogen in a glass bulb has a mass of 245 mg what is its mass in kilograms

Answer:

245*10⁻⁶ kg

Explanation:

Given:

Mass of nitrogen in a glass bulb = 245 mg

In order to convert mass from mg (milligrams) to kg (kilograms) use the following relation

1 mg = 0.001 gram = 10⁻³ g

1 g = 0.001 kg = 10⁻³ kg

Therefore,

1 mg = 10⁻⁶ kg

The given mass of 245 mg would correspond to :

\frac{245 mg * 10^{-6} kg}{1 kg} = 245*10^{-6} kg

ANSWERED AT 28/02/2020 - 10:55 AM


QUESTION POSTED AT 28/02/2020 - 10:55 AM

In the treatment of domestic water supplies, chlorine is added to the water to form chloric(I) acid,HClO. Cl2(aq) + H2O(I) → H+(aq) + Cl–(aq) + HClO(aq) The HClO reacts further to give the chlorate(I) ion.(CLO-) HClO(aq) + H2O(I) → H3O+(aq) + ClO–(aq) Both HClO and ClO–kill bacteria by oxidation. What is the change in oxidation number of chlorine in forming the chlorate(I) ion from the aqueous chlorine? PLEASE SHOW WORKING :)

Chlorine goes from Cl₂ to ClO⁻.

Oxidation state of Cl in Cl₂ is zero whereas in ClO⁻ it is +1. Hence change in oxidation state of Chlorine is 1.

Calculation of oxidation number of Cl in ClO⁻ or HClO⁻ :
Let x be oxidation number of Cl in ClO⁻ the. Now since the net charge on ClO⁻ is -1, sum of oxidation number of all must be equal to -1. 


Therefore,
x + (-2) = -1 .....[ oxidation number of O is -2]
∴ x = 2-1 = +1
Therefore oxidation number of Cl in ClO⁻ is +1

ANSWERED AT 28/02/2020 - 10:47 AM


QUESTION POSTED AT 28/02/2020 - 10:47 AM

10.0 grams of octane are burned in a bomb calorimeter containing 2.00 × 102 g H2O. How much energy, in kilocalories, is released if the water temperature increases by from 25.00oC to 37.00oC?

An electron jumps from energy level 1 to energy level 2 by absorbing a photon of ... How many moles of methane are produced when 25.1 moles of carbon ... 10.0 grams of octane are burned in a bomb calorimeter containing 2.00 × 102 g H2O. ... is released if the water temperature increases by from 25.00oC to 37.00oC?

ANSWERED AT 28/02/2020 - 10:36 AM


QUESTION POSTED AT 28/02/2020 - 10:36 AM

Explain why are hydrogen and oxygen considered as wheares water as a compound?

Hydrogen and oxygen are different elements.

when two or more elements combine, they form a compound

hence, two molecules of hydrogen and one molecule of oxygen combine to form water as a compound

ANSWERED AT 28/02/2020 - 08:11 AM


QUESTION POSTED AT 28/02/2020 - 08:11 AM

Explain why are hydrogen and oxygen considered wheares water as a compound

Hydrogen and oxygen are different elements ...
but when two or more elements combine... it is known as a compound.. hence hydrogen and oxygen together form a compound

ANSWERED AT 28/02/2020 - 08:10 AM


QUESTION POSTED AT 28/02/2020 - 08:10 AM

In a hydrogen fuel cell, hydrogen gas and oxygen gas are combined to form water. write the balanced chemical equation describing this reaction (using lowest whole-number coefficients.

Answer:

2H₂ + O₂ → 2H₂O

Explanation:

The problem tells us that hydrogen gas (H₂) and oxygen gas (O₂) are the reactants, while water (H₂O) is the only product. Thus, the reaction is:

H₂ + O₂ → H₂O

In order to balance this equation, we begin with counting the atoms of O present in the left side and in the right side of the equation. Because there are two O atoms in the left but only one on the right, we add a coefficient of 2 in the right side:

H₂ + O₂ → 2H₂O

Now we count the H atoms, there are 2 in the left and 4 in the right, so we add a coefficient of 2 for the hydrogen gas:

2H₂ + O₂ → 2H₂O

Now there are 4 H atoms in both sides, and 2 O atoms in both sides, so the equation is balanced.

ANSWERED AT 28/02/2020 - 07:55 AM


QUESTION POSTED AT 28/02/2020 - 07:55 AM