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4 years ago

Select all that apply.

2 answers:

7 0

To improve the efficiency of fireplaces, technologies such as A. addition of catalytic combustors and B. addition of boilers are used in so far. Addition of catalytic combustors hastens the process and makes use of inerts that cannot be used. The addition of boilers also adds to the efficiency by converting fluids to higher temperatures,

Komok [63]4 years ago

4 0

Answer:

addition of catalytic combustors

use of masonry

use of venting systems

Explanation:

Select all that apply.

Which of the following techniques have been employed to improve the efficiency of fireplaces?

addition of catalytic combustors

addition of boilers

use of masonry

use of venting systems

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Large crystals are made from the slow cooling of magma. a. True b. False

Step2247 [10]

I would have to say the answer is a. True.

5 0

3 years ago

Read 2 more answers

N2+3H2-2NH3

NemiM [27]

102 grams of ammonia is formed when 3 moles of nitrogen and 6.7 moles of hydrogen reacts.

Explanation:

The equation given is of Haeber's process in which the nitrogen is limiting factor in the ammonia formation and hydrogen if in excess gets delimited.

We know that 1 mole of Nitrogen gives 2 moles of ammonia.

We have 3 moles of nitrogen here,

So, 6 moles of ammonia will be form

so from the formula

no of moles=mass/atomic mass

mass= no. of moles*atomic mass

= 6*17

= 102 grams of ammonia will be formed.

So, 6 moles or 102 grams of ammonia is formed when 3 mole of nitrogen and 6.7 mole of hydrogen reacts.

7 0

4 years ago

How many Joules are released to cool 250.0 grams of liquid water from 100°C to 0°C? The specific heat of water is 4.180 J/g.C.

nlexa [21]

$\bold{\huge{\orange{\underline{ Solution}}}}$

$\bold{\underline{ Given :- }}$

We have 250g of liquid water and it needs to be cool at temperature from 100° C to 0° C
Specific heat of water is 4.180J/g°C

$\bold{\underline{ To \: Find :- }}$

We have to find the total number of joules released.

$\bold{\underline{ Let's \:Begin:- }}$

We know that,

Amount of heat energy = mass * specific heat * change in temperature

That is, 

$\sf{\red{ Q = mcΔT }}$

Subsitute the required values in the above formula :-

$\sf{ Q = 250 × 4.180 ×(0 - 100 )}$

$\sf{ Q = 250 × 4.180 × - 100 }$

$\sf{ Q = 250 × - 418}$

$\sf{\pink{ Q = - 104,500 J }}$

Hence, 104,500 J of heat is released to cool 250 grams of liquid water from 100° C to 0° C.

$\bold{\underline{ Now :- }}$

We have to tell whether the above process is endothermic or exothermic :-

Here, In the above process ΔT is negative and as a result of it Q is also negative that means above process is Exothermic

Exothermic process :- It is the process in which heat is evolved .
Endothermic process :- It is the process in which heat is absorbed .

4 0

2 years ago

The alkali metals play virtually the same general chemical role in all their reactions. (b) How is it based on atomic properties

vfiekz [6]

b) It is based on atomic properties as alkali metals requires 7 more electrons to complete their outer orbit. And they try to give those electrons to other elements to obtain noble gas configuration.

Noble gases are the gases which do not react easily with anything. They are also called as Inert gases, and belongs to group 18 of the periodic table.

Alkali metals are the substances which are found in Group I of a periodic table. Mostly the elements which are present are:

Lithium (Li)

Sodium (Na)

Potassium (K)

Rubidium (Rb)

Cesium (Cs)

Francium (Fr)

Properties of alkali metals are: Soft, shiny reactive metals. They are soft enough to cut with knife. Metals react with water and air quickly and gets tarnish, so pure metals are stored in container by dipping them in oil to prevent oxidation.

To know more about Alkali metals, refer to this link:

brainly.com/question/18153051

#SPJ4

6 0

2 years ago

Match the following

Ket [755]

Answer:

Ai --> Bii

Aii --> Bi

Aiii --> Bv

Aiv --> Biii

Av --> Biv

Explanation:

For Ai, naphthalene sublimes directly from a solid to gas when heated at around 80 degree Celsius.

For Aii, Ozone has a molecular formula of O₃.

For Aiii, weeds are normally considered as "unwanted" plants. Many people may consider using herbicides to clear the weeds in their gardens.

For Aiv, filtration is a physical method for separating solid and liquid from a mixture. A filter paper is normally used, in which the complex structure of the paper only allows fluid to pass through it, but not the solid ones. The solid left behind on the filter paper is called "residue".

For Av, photosynthesis is a chemical reaction that occurs in the leaves of a plant, which produces food for plants to survive. Carbon dioxide, water and light are required for photosynthesis to take place.

4 0

3 years ago