All categories

4 years ago

What holds combinations of atoms together in molecules? protons and electrons atomic magnetism chemical bonds nuclear forces?

2 answers:

8 0

<span>Chemical bonds hold combinations of atoms together in molecules. These chemical bonds, called covalent bonds or molecular bonds, are formed when two atoms share electron pairs. Some other types of chemical bonds are ionic bonds and metallic bonds.</span>

ElenaW [278]4 years ago

6 0

Chemical bonds hold combinations of atoms together in molecules...

You might be interested in

What is the name of this compound <br>Fe(NH3)5Cl4

aev [14]

Answer:

it a complex salt.......

3 0

3 years ago

Which of the following is an example of an environmental problem caused by chemicals

Neko [114]

Answer:

Explanation:

All of the other options are ways that could help the environment from the chemicals, but if they just continue to use the chemicals then it would hurt the environment

7 0

3 years ago

How many moles of carbon dioxide, co2, are produced if 5.87 moles of glucose, c6h12o6, react?

almond37 [142]

The balanced equation for the reaction is as follows
C₆H₁₂O₆ + 6O₃ --> 6CO₂ + 6H₂O
stoichiometry of glucose to CO₂ is 1:6
when 1 mol of glucose reacts - 6 mol of CO₂ are formed
therefore when 5.87 mol of glucose reacts - 6 x 5.87 mol = 35.22 mol
therefore 35.2 mol of CO₂ is formed

3 0

3 years ago

In the manufacture of paper, logs are cut into small chips, which are stirred into an alkaline solution that dissolves several o

Kitty [74]

Answer:

The estimated feed rate of logs is 14.3 logs/min.

Explanation:

The product of the process is 2000 tons/day of dry wood pulp, of 85 wt% of cellulose. That represents (2000*0.85)=1700 tons/day of cellulose.

That cellulose has to be feed by the wood chips, which had 47 wt% of cellulose in its composition. That means you need (1700/0.47)=3617 tons/day of wood chips to provide all that cellulose.

Th entering flow is wood chips with 45 wt% of water. This solution has an specific gravity of 0.640.

To know the specific gravity of the wood chips we have to write a volume balance. We also know that Mw=0.45*M and Mc=0.55*M.

$V=V_c+V_w\\\\M/\rho=M_c/\rho_c+Mw/\rho_w\\\\M/\rho=0.55*M/\rho_c+0.45*M/\rho_w\\\\1/\rho=0.55/\rho_c +0.45/\rho_w\\\\0.55/\rho_c=1/\rho-0.45/\rho_w\\\\0.55/\rho_c=1/(0.64*\rho_w)-0.45/\rho_w=(1/\rho_w)*(\frac{1}{0.64}-\frac{0.45}{1} )\\\\0.55/\rho_c=1.1125/\rho_w\\\\\rho_c=\frac{0.55}{1.1125}*\rho_w= 0.494*\rho_w$

The specific gravity of the wood chips is 0.494.

The average volume of a log is

$V_l=(\pi*D^{2} /4)*L=(3.1416*\frac{8^{2} \, in^{2} }{4} )*9ft*(\frac{12 in}{1ft})= 21714 in^{3}=12.57 ft^{3}$

The weight of one log is

$M=\rho*V=0.494*\rho_w*12.57 ft^{3}\\\\M=0.494*62.4\frac{lbm}{ft^{3} }*12.57ft^{3}\\\\M=387.5lbm$

To provide 3617 ton/day of wood chips, we need

$n=\frac{supply}{M_{log}}=\frac{3617 tons/day}{387.5 lbm}*\frac{2204lbm}{1ton}\\\\n=20573 logs/day=14.3 logs/min$

The feed rate of logs is 14.3 logs/min.

7 0

3 years ago

Read 2 more answers

Liquid Mercury has a density of 13.55 g/cm3 at room temperature (20.0 ° C).

yawa3891 [41]

Answer:

A long glass tube with one end open and the other end sealed was completely filled with mercury, then it was stood on end with the open end in a container filled with mercury.

If the tube is relatively short, it will still be filled with mercury all the way to the top. If it's long enough, the column of mercury will not reach the top. The air pressure on the surface of the mercury pool that the tube sits in is what supports the mercury. When the weight of a 1 cm^2 column of mercury is greater than the air pressure per cm^2, it can't be supported by that pressure. The top of the tube will have an almost perfect vacuum, with only a tiny amount of mercury vapor in it.

The height of a column of water or mercury that can be supported by air pressure depends on, and is proportional to, the density of the water or mercury.

How you're supposed to get the answers depends on what units are used to define 1 bar of pressure. Your textbook or lecture notes should give you the value and units of a bar. If you're supposed to look it up, you'll find a variety of different combinations, including 750.06 mm of Hg or 1019.72cm of H 2 O. That would actually give you the answers directly.

750.06 m m ≈ 0.75 m of H g

1019.72 c m ≈ 10.20 m of water

If you're supposed to calculate everything, you'll need to use 1 bar = 1 x 105 N / m 2. Then you'll have to look up the g r a v i t a t i o n constant and calculate the weight of a column of mercury or water. Note that g rams and k i l o g r a m s are units of mass, not weight, which is a force. The unit of force in the m e t r i c system is the N e w t o n. This is confusing because we measure weight in pounds, which is a force. Most of the rest of the world measures "weight" in k i l o g r a m s, which is really mass.

How is 1 bar defined for you?

If it's m m H g, just multiply that by 13.6 to get the height for a column of water.

If it's a force per unit area:

We can calculate the force (weight) of H. g using the g r a v i t a t i o n constant and the given density, then go from there."

Explanation:

I do not own this information

6 0

3 years ago