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2 years ago

Select all the correct answers.

Chemistry

1 answer:

pochemuha2 years ago

8 0

Out of all given option, the following statements are true about a system:

A system is a group of objects analyzed as one unit.
Energy that moves across system boundaries is conserved

Answer: Option A and B

Explanation:

A system is "a complicated item whose parts or segments are identified with probably a portion of different segments", it very well may be material or calculated. All systems have piece, structure, and condition, yet just material systems have instruments (or forms), and just some material systems have shape.

As per systems, all articles are systems or segments of another system. For instance, a nuclear core is a physical material system made out of protons and neutrons related by solid atomic association; a cell is a natural material system made out of related organelles by non-covalent synthetic securities and metabolic pathways; and a logical hypothesis is a consistent reasonable system made out of theories, definitions, and hypotheses related by relationship and conclusion.

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5 points

Orlov [11]

Answer:

The correct option is (a).

Explanation:

We need to find the product of given numbers.

First number = 29.5

Second number = 240

Product of two numbers = 29.5 × 240

= $\dfrac{295}{10}\times 240$

Zeroes from numerator and denominator get cancelled.

So,

$=295\times 24\\\\=7080$

Hence, the correct option is (a).

7 0

2 years ago

Which element is reduced in the following reaction: 2Mg+O₂ → 2MgO if Mg goes from 0 to +2 and O goes from 0 to -2?

Lyrx [107]

Answer:

Explanation:

The element which is oxidized is the element that losses electrons and its oxidation state be more positive.

The element which is reduced is the element that gain electrons and its oxidation state be more negative.

O goes from 0 to -2, so, it is the element that is reduced.

8 0

2 years ago

How many milligrams of sodium sulfide are needed to completely react with 25.00 ml of a 0.0100 m aqueous solution of cadmium nit

NARA [144]

Na₂S(aq) + Cd(NO₃)₂(aq) = CdS(s) + 2NaNO₃(aq)

v=25.00 mL
c=0.0100 mmol/mL
M(Na₂S)=78.046 mg/mmol

n(Na₂S)=n{Cd(NO₃)₂}=cv

m(Na₂S)=M(Na₂S)n(Na₂S)=M(Na₂S)cv

m(Na₂S)=78.046*0.0100*25.00≈19.5 mg

5 0

3 years ago

Read 2 more answers

Concentrated hydrogen peroxide solutions are explosively decomposed by traces of transition metal ions (such as Mn or Fe): 2H2O2

zalisa [80]

Answer:

23.0733 L

Explanation:

The mass of hydrogen peroxide present in 125 g of 50% of hydrogen peroxide solution:

$Mass=\frac {50}{100}\times 125\ g$

Mass = 62.5 g

Molar mass of $H_2O_2$ = 34 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus, moles are:

$moles= \frac{62.5\ g}{34\ g/mol}$

$moles= 1.8382\ mol$

Consider the given reaction as:

$2H_2O_2_{(aq)}\rightarrow2H_2O_{(l)}+O_2_{(g)}$

2 moles of hydrogen peroxide decomposes to give 1 mole of oxygen gas.

Also,

1 mole of hydrogen peroxide decomposes to give 1/2 mole of oxygen gas.

So,

1.8382 moles of hydrogen peroxide decomposes to give $\frac {1}{2}\times 1.8382 mole of oxygen gas. Moles of oxygen gas produced = 0.9191 molGiven: Pressure = 746 torr
The conversion of P(torr) to P(atm) is shown below:
[tex]P(torr)=\frac {1}{760}\times P(atm)$

So,

Pressure = 746 / 760 atm = 0.9816 atm

Temperature = 27 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

So,

T₁ = (27 + 273.15) K = 300.15 K

Using ideal gas equation as:

PV=nRT

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

0.9816 atm × V = 0.9191 mol × 0.0821 L.atm/K.mol × 300.15 K

⇒V = 23.0733 L

8 0

2 years ago

How many moles of helium atoms are there in

fredd [130]

a is the correct answer .

2.4 × 10^24

6 0

3 years ago