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3 years ago

6

In the modern periodic table, each element is represented by its _____ symbol. The number above each symbol is its atomic number

. Atomic numbers increase from left to right and from top to bottom in the table.

2 answers:

Margarita [4]3 years ago

6 0

Answer:

chemical

Explanation:

QveST [7]3 years ago

4 0

The answer is chemical

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You need to help a hunting companion with a deep, open chest wound. What should you do first?

Natalija [7]

The choice for this question from my perspective was letter D which was... <span>Cover the wound with the palm of your hand until a bandage is located.</span>

4 0

4 years ago

In the Energy and Specific Heat lab, you measure the temperature change of water to study the specific heat of a metal. What sta

pshichka [43]

The question is incomplete, the complete question is;

In the Energy and Specific Heat lab, you measure the temperature change of water to study the specific heat of a metal. What statement explains the relationship between the water and the metal you are studying? Select one: O The heat lost by the metal plus the heat gained by the water equals 100. O The temperature change of the metal is equal to the temperature change of the water. O The heat lost by the metal is equal to the heat gained by the water. The initial temperature of the metal equals the initial temperature of the water

Answer:

The heat lost by the metal is equal to the heat gained by the water.

Explanation:

When the piece of metal is put into water, heat is lost by the metal and gained by the water.

Recall that energy is conserved hence heat lost by metal must be equal to heat gained by water.

Thus, the relationship between the metal under study and the water is that the metal looses heat to the water and heat lost by metal is equal to heat gained by water.

3 0

3 years ago

Many moderately large organic molecules containing basic nitrogen atoms are not very soluble in water as neutral molecules, but

alukav5142 [94]

Answer:

a) For nicotine, the protonated form is the present in stomach.

b) For caffeine, the neutral base form is the present in stomach.

c) For Strychinene, the protonated form is the present in stomach.

d) For quinine, the protonated form is the present in stomach.

Explanation:

In a basic dissociation for molecules with basic nitrogen, the equilibrium is:

A + H₂O ⇄ AH⁺ + OH⁻

<em>Where A is neutral base and AH⁺ is protonated form</em>

The basic dissociation constant, kb, is:

$K_{b} = \frac{[AH^+][OH^-]}{[A]}$

As pH in stomach is 2,5:

[OH] = $10^{-[14-pH]}$

[OH] = 3,16x10⁻¹² M

Thus:

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$ <em>(1)</em>

Using (1) it is possible to know if you have the neutral base or the protonated form, thus:

(a) nicotine Kb = 7x10^-7

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$\frac{7x10^{-7}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$221359 = \frac{[AH^+]}{[A]}$

[AH⁺}>>>>[A]

For nicotine, the protonated form is the present in stomach

(b) caffeine,Kb= 4x10^-14

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$\frac{4x10^{-14}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$0,0127 = \frac{[AH^+]}{[A]}$

[AH⁺}<<<<[A]

For caffeine, the neutral base form is the present in stomach

(c) strychnine Kb= 1x10^-6

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$\frac{1x10^{-6}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$314456 = \frac{[AH^+]}{[A]}$

[AH⁺}>>>>[A]

For Strychinene, the protonated form is the present in stomach

(d) quinine, Kb= 1.1x10^-6

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$\frac{1,1x10^{-6}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$347851= \frac{[AH^+]}{[A]}$

[AH⁺}>>>>[A]

For quinine, the protonated form is the present in stomach.

I hope it helps!

7 0

3 years ago

Which of the following elements has two valence electrons?<br> Na <br> MG<br> AL <br> S

goldfiish [28.3K]

Mg
......
Electron configuration:
²⁴₁₂Mg: 1s² 2s² 2p⁶ 3s²

>>> 3s² - valence shell with 2 valence electrons

4 0

4 years ago

Read 2 more answers

There are 3.0 g of NO and 3.0 g of CO reacting. what is the limiting reactant ?

xxTIMURxx [149]

Answer:

NO will be the limiting reagent.

Explanation:

The balanced equation is:

2 NO + 2 CO → N₂ + 2 CO₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

NO: 2 moles
CO: 2 moles
N₂: 1 mole
CO₂: 2 moles

Being the molar mass of each compound:

NO: 30 g/mole
CO: 28 g/mole
N₂: 28 g/mole
CO₂: 44 g/mole

Then by stoichiometry the following quantities of mass participate in each reaction:

NO: 2 moles* 30 g/mole= 60 g
CO: 2 moles* 28 g/mole= 56 g
N₂: 1 mole* 28 g/mole= 28 g
CO₂: 2 moles* 44 g/mole= 88 g

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, you can use a simple rule of three as follows: If 56 grams of CO react with 60 grams of NO, 3 grams of CO react with how much mass of NO?

$mass of NO=\frac{3 grams of CO*60 grams of NO}{56 grams of CO}$

mass of NO= 3.21 grams

But 3.21 grams of NO are not available, 3 grams are available. Since you have less moles than you need to react with 3 grams of CO, <u><em>NO will be the limiting reagent. </em></u>

<u><em></em></u>

4 0

3 years ago