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4 years ago

PLEASE HELP ASAP

Chemistry

2 answers:

aliina [53]4 years ago

8 0

Answer:

A and D takes much slower

Explanation:

Here, we want to select, out of the four given reactions, the one that is slower than the other two

The answers in these case are reactions 1 and 4 ( A and D)

The two reactions show what is called rust (as directly seen in reaction 4)

When we speak of rust, we simply mean a reaction that occurs over time

For example, non coated roofings of houses doesn’t get to change color at an instant

The color degradation that occurs is something that takes some time from the initial time they were used to roof the house

Hence, from these analogy, we can see that these reactions need an an external support to thrive or to come into existence

These external supports are natural forces and they contributing efforts occur over time and cannot be seen immediately

These reactions are thus ones that take much slower time than conventional laboratory reactions in the case of the formation of the precipitate or a reaction that requires a low flash point temperature such as that of black powder to produce such explosive effects

So in conclusion, what we are saying is that the two selected reactions are subjected to the availability of some conditions and may take time to manifest and these absolutely differentiates them from reactions that are spontaneous such as the one having an explosive effect or the other one leading to the formation of a precipitate which takes far less times

Dimas [21]4 years ago

3 0

Answer:

a and d

Explanation:

a p e x

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Question 1(Multiple Choice Worth 3 points)

Bingel [31]

1) Answer:

moles of oxygen (n) = 1.86 moles

Explanation:

according to Boyle's law the formula to solve this problem is:

PV=nRt

when P is the pressure which equal 1.25 atm

and V is the volume which equal 37.5 L

n is the number of moles which we need to calculate it

R is constant which equal 0.082

t is the temperature in kelvin

By substitution:

1.25*37.5 = n * 0.082 * 307

So n = 1.86 moles

2) Answer:

the volume of oxygen gas = 34 L

Explanation:

at standard temperature and pressure (STP) 1 mole of gas will equal = 22.4L

So when we have 1.5 moles of oxygen at standard temperature and pressure (STP) so we will estimate it like that

1.5 moles *22.4 L/ 1 mole = approximately 34 L

3) Answer:

The volume of H2 = 2.29 L

Explanation:

according to the Balanced equation we can see that the molar ratio between Zn and H2 1 : 1

so to know the number of moles of H2 we will get it for Zn first :

number of moles Zn = mass of Zn / molar mass Zn

= 5.98 / 65.39 =0.0914 moles

so number of moles H2 = 0.09 moles

by substitution in the following formula:

PV = nRT

0.978 * V = 0.09 * 0.082 * 298

so The volume of H2 = 2.29 L

4) Answer:

Volume of O2 = 1.4 L

Explanation:

first we have to balance the equation:

2Na2O2 +2CO2 → 2Na2CO3 + O2

2 mole CO2 give 1 mole of O2 so the molar ratio is 2:1

at STP 1 mole of gas will equal = 22.4 L

??? moles of CO2 = 2.8

n CO2 = 0.125 moles so n O2 = 0.125 /2 = 0.0625 moles

so when 1 mole of as = 22.4

0.0625 moles O2 = ???

Volume of O2 =0.0625 moles * 22.4 L/ 1 mole

= 1.4 L

5) Answer:

the initial quantity of sodium metal used = 17.2 gram

Explanation:

at STP 1 mole of gas will equal = 22.4 L

so moles of H2 equal ?? when 8.40 liters of H2 gas were produced

so moles of H2 = 8.4/22.4 =0.375 moles

and according to the balanced equation the molar ratio between H2 ans Na is 1 : 2

so number of moles for Na = 0.375 *2 = 0.75 moles

to get the initial quantity of sodium metal (mass Na) = number of moles * molar mass

mass Na = 0.75 moles * 23 gm/mole= 17.25

6) Answer:

False

Explanation:

because STP means standard temperature and pressure. and the Standard temperature must be 273 K and the standard pressure must be 1 atm but in the question the temperature is 298 K not 273 K so , It is not a standard temperature

7) Answer:

22.4 liters

Explanation:

1 mole of gas will equal = 22.4 L

because at the Standard temperature must be 273 K and the standard pressure must be 1 atm

so V = nRT/P

=1 mole * 0.082 * 273 K / 1 aTm

= 22.4 liters

4 0

4 years ago

In the reaction of silver nitrate with copper metal, metallic silver comes out of solution, and the solution turns blue. This as

aalyn [17]

Answer:

Single displacement reaction.

Explanation:

Hello!!

In this case, since the reaction between silver nitrate and copper metal is:

$2AgNO_3(aq)+Cu(s)\rightarrow 2Ag(s)+Cu(NO_3)_2(aq)$

As silver was forming silver nitrate, due to the presence of copper, which has the capacity to displace silver out of the salt, we notice the formation of solid silver and a resulting copper (II) nitrate which is blue in aqueous solution.

Therefore, this is a single displacement reaction, because the the lonely copper displaced the silver.

Best regards!

7 0

3 years ago

Help plz. ASAP!!!!

GuDViN [60]

Answer:

Option A, 931 Kg

Explanation:

As we know that weight is equal to the product of mass and acceleration due to gravity.

Thus,

$W = M * 9.8$ m/s2

Substituting the given values in above equation, we get -

$W = 95 * 9.8 \\W = 931$ Kg

Hence, option A is correct

4 0

3 years ago

Write the name and the symbol of the element that fits each of the following descriptions: a) the alkaline earth metal in the si

brilliants [131]

Explanation:

a) Barium

b) The metalloid in third period is Silicon

c) Group 4A (or IVA) of the periodic table includes the nonmetal carbon (C)

d) At this temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine and astatine are solids.

e) osmium

f) chlorine (Cl, element 17) are a gas at room temperature, and is found as diatomic molecule (Cl2).

8 0

4 years ago

Select the correct answer from each drop-down menu.

shtirl [24]

Answer:

A (Hypothesis) is scientific knowledge published through direct observation and remains constant scientific knowledge can change when scientists (generate hypothesis)

7 0

3 years ago