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Simora [160]
2 years ago
10

A student hears in chemistry class that a certain object is made of a pure substance. What can the student conclude about the ob

ject based on this information?
Chemistry
2 answers:
umka21 [38]2 years ago
5 0
It has no other elements
spin [16.1K]2 years ago
5 0

<u>Answer:</u> The object is made up either elements or a compound.

<u>Explanation:</u>

A pure substance is defined as the substance which is formed by same or different type of atoms which are chemically combined in a fixed ratio by mass.

Elements and compounds are considered as pure substances.

Elements are formed by the combination of similar type of atoms and compounds are formed by the combination of different type of atoms.

We are given:

An object is made of a pure substance.

Hence, the object is made up either elements or a compound.

You might be interested in
How many grams of NH3 can be prepared from 85.5 grams of N2 and 17.3 grams of H2 ?
Tcecarenko [31]
N2 + 3H2 ---> 2NH3

mass of N2 = 28g
mass of H2 = 2g
mass of NH3 = 17g

according to the reaction:
28g N2----------------- 3*2g H2
85,5g N2-------------------- x
x = 18,32g H2 >>>  so, nitrogen is excess

according to the reaction:
2*3g H2---------------------- 2*17g NH3
17,3g H2 ------------------------- x
x = 98,03g NH3

<u>answer: 98,03g of NH3</u>
4 0
2 years ago
A particular first-order reaction has a rate constant of 1.35 × 102 s-1 at 25.0°c. what is the magnitude of k at 75.0°c if ea =
IgorC [24]
According to this formula:
K= A*(e^(-Ea/RT) when we have K =1.35X10^2 & T= 25+273= 298K &R=0.0821
Ea= 85.6 KJ/mol So by subsitution we can get A:
1.35x10^2 = A*(e^(-85.6/0.0821*298))
1.35x10^2 = A * 0.03
A= 4333
by substitution with the new value of T(75+273) = 348K & A to get the new K
∴K= 4333*(e^(-85.6/0.0821*348)
  = 2.16 x10^2
8 0
2 years ago
The volume of a single strontium atom is 4.15×10-23 cm3. What is the volume of a strontium atom in microliters
Ivenika [448]

Answer:-  4.15*10^-^2^0\mu L

Solution:- It is a volume unit conversion problem where we are asked to convert the volume from cm^3 to microliters.

We know that:

1cm^3 = 1 mL

1mL=10^-^3L

and, 1L=10^6\mu L

Let's use these conversions factors for the desired conversion using dimensional as:

4.15*10^-^2^3cm^3(\frac{1mL}{1cm^3})(\frac{10^-^3L}{1mL})(\frac{10^6\mu L}{1L})

= 4.15*10^-^2^0\mu L

So, the answer is  4.15*10^-^2^0\mu L .

7 0
2 years ago
What is the name of the functional group that is attached to this hydrocarbon? The first and last of a chain of three carbons ar
disa [49]

Answer:

Ketone

Explanation:

As you are stating here, we have a carbonated chain of three carbons, and the first and last has 3 Hydrogens, then this means that we have CH₃ . The center carbon is a carbon double bonded to oxygen.

In general terms this belongs to the carbonyl group. However, this alone does not represent a functional group, but when it's in a chain with other radycals or chains, it becomes a functional group.

In this case, the molecule you are talking here is the following:

CH₃ - CO - CH₃

This molecule is known as the Acetone, and has the general form of:

R - CO - R'

Which belongs to a ketone as a functional group.

4 0
2 years ago
NH4NO3, whose heat of solution is 25.7 kJ/mol, is one substance that can be used in cold pack. If the goal is to decrease the te
makvit [3.9K]

Answer:

There are necessaries 35,2g of NH₄NO₃ per 100,0g of water to decrease the temperature of the solution from 25,0°C to 5,0°C

Explanation:

To decrease the temperature of the solution there are necessaries:

4,184J/g°C×(5,0°C-25,0°C)×(100,0g+X) = -Y

8368J + 83,68J/gX = Y <em>(1)</em>

Where x are grams of NH₄NO₃ you need to add and Y is the energy that you need to decrease the heat.

Also, the energy Y will be:

Y = 25700J/mol×\frac{1mol}{80,043g}X

Y = 321J/g X <em>(2)</em>

Replacing (2) in (1)

8368J + 83,68J/g X = 321J/g X

8363J = 237,32J/gX

<em>X = 35,2g</em>

<em />

Thus, there are necessaries 35,2g of NH₄NO₃ per 100,0g of water to decrease the temperature of the solution from 25,0°C to 5,0°C

I hope it helps!

6 0
2 years ago
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