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3 years ago

Which of the following statements is true?

Chemistry

2 answers:

Lera25 [3.4K]3 years ago

3 0

The statement which is true is

metals lose electrons to become cations

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

metals tends to loss electrons to attain noble gas electrons configuration.
When metal loses electrons they form a positive charged ions.
The positively charged ion is known as cations.
for example sodium metal (Na) loses 1 electron to form a cation with a charge of positive 1 ( Na^+)

Tems11 [23]3 years ago

3 0

Answer:

Metals lose electrons to become cations.

Explanation:

You have to lose electrons for it to be a cation, therefore B and D are false and can be eliminated.

Nonmetals tend to gain electrons and become anions, therefore C is incorrect and can be eliminated.

A is the only answer left, and it is scientifically correct.

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A 2.4L balloon filled with helium at room temperature 25oC is put into liquid nitrogen

Stels [109]

Answer:

V₂ = 0.62 L

Explanation:

Given data:

Initial volume = 2.4 L

Initial temperature = 25°C

Final temperature = -196°C

Final volume = ?

Solution:

Initial temperature = 25°C (25+273 = 298 K)

Final temperature = -196°C ( -196+273 = 77 K)

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

V₂ = V₁T₂/T₁

V₂ = 2.4 L × 77 K / 298 k

V₂ = 184.8 L.K / 298 K

V₂ = 0.62 L

5 0

2 years ago

As you go down a family or group on the periodic table *

pickupchik [31]

Answer:

The elements become less reactive.

Explanation:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction and reactivity increases because of greater electron affinity.

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased. The electron affinity decreases because of shielding effect and thus atom become less reactive.

7 0

3 years ago

Which of the following would have the largest pKa?

garri49 [273]

Answer:

CH3CH2NH3+/CH3CH2NH2 would have the largest pKa

Explanation:

To answer this question we must know Kb of CH3CH2NH2 is 5.6x10⁻⁴, and for C6H5NH2 is 4.0x10⁻¹⁰. And the CH3CH2NH3+ and C6H5NH3+ are related with these substances because are their conjugate base. That means:

pKa of CH3CH2NH3+ = CH3CH2NH2; C6H5NH3+ = C6H5NH2

Also, Kw / Kb = Ka

Thus:

pKa of CH3CH2NH3+/CH3CH2NH2 is:

Kw / kb = Ka = 1.79x10⁻¹¹

-log Ka = pKa

pKa = 10.75

pKa of C6H5NH3+/ C6H5NH2 is:

Kw / kb = Ka = 2.5x10⁻⁵

-log Ka = pKa

pKa = 4.6

That means CH3CH2NH3+/CH3CH2NH2 would have the largest pKa

5 0

3 years ago

A client who weighs 70 kg is receiving a solution of 0.9% sodium chloride (normal saline) 500 ml with dopamine 800 mg at 5 ml/ho

nordsb [41]

The mcg/kg/minute the client is receiving is 1.904 mcg/kg/min whose weight is 70 kg.

1 milligram (mg) = 1000 micrograms (mcg) or 0.001 grams (g) 1 g = 1000 mg 1 kilogram (kg) = 1000 g 1 kg = 2.2 pound (lb) 1 liter (L) = 1000 milliliters (mL)

The number of mcg/kg/minute = flow rate × concentration ÷ mass of client

Flow rate = 12 ml/hour = 12 ml/hour × 1 hr/60 min = 0.2 ml/min

Concentration = mass of dopamine/volume

where

mass of dopamine = 800 mg and

volume = 500 ml

Concentration =800 mg/500 ml

= 1.6 mg/ml

= 1.6 mg/ml × 1000 mcg/mg

= 1600 mcg/ml

mass of client = 70 kg

Calculating mcg/kg/minute

So, substituting the variables into the equation, we have

mcg/kg/minute = flow rate × concentration ÷ mass of client

mcg/kg/minute = 0.08 ml/min × 1600 mcg/ml ÷ 70 kg

mcg/kg/minute = 320 mcg/min ÷ 70 kg

mcg/kg/minute = 1.904 mcg/kg/min

Thus, the mcg/kg/minute the client is receiving is 1.904 mcg/kg/min

Learn more about mcg/kg/minute here:

brainly.com/question/4253005

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1 year ago

4. How many weeks are equal to 2.94 x 10 to the power of 6 minutes?

OverLord2011 [107]

Answer:

292 weeks

Explanation:

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3 years ago