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Georgia [21]
2 years ago
11

Phase changes are chemical changes. True False ...?

Chemistry
2 answers:
tekilochka [14]2 years ago
8 0
False
Phase changes are physical changes and can be easily reverted by adjusting pressure or temperature. 
marusya05 [52]2 years ago
5 0
Hi , the answer is false.
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What is the molality of a solution that contains 1.34 moles of NaCl in 2.47 kg of solvent
dsp73

The molality is 0.54 M when 1.34 moles of NaCl is present in 2.47 kg of solvent.

<u>Explanation:</u>

Molality is the measure of how much of amount of solute is dissolved in the solvent. So it is calculated as the ratio of moles of solute to the grams of solvent.

         \text {Molality}=\frac{\text {Moles of solute}}{\text {Mass of solvent}}

As in this case, the solute is NaCl and solvent is unknown. So the moles of solute is given as 1.34 moles and the mass of solvent is given as 2.47 kg.

Hence, \text { molality }=\frac{1.34}{2.47}= 0.54 \mathrm{M}

Thus, the molality is 0.54 M when 1.34 moles of NaCl is present in 2.47 kg of solvent.

8 0
3 years ago
You have 16.7 grams of hydrogen and 15.4 grams of oxygen in a synthesis rxn. Which is the limiting reagent?
sleet_krkn [62]

Answer:

oxygen is limiting reactant

Explanation:

Given data:

Mass of hydrogen = 16.7 g

Mass of oxygen = 15.4 g

Limiting reactant = ?

Solution:

Chemical equation:

2H₂ + O₂   →   2H₂O

Number of moles of hydrogen:

Number of moles = mass/ molar mass

Number of moles = 16.7 g/ 2 g/mol

Number of moles = 8.35 mol

Number of moles of oxygen:

Number of moles = mass/ molar mass

Number of moles = 15.4 g/ 32 g/mol

Number of moles = 0.48 mol

Now we will compare the moles of both reactant with product,

                 

                             H₂           :          H₂O

                              2            :            2

                             8.35        :            8.35

                             O₂           :          H₂O

                               1            :            2

                             0.48        :        2×0.48 = 0.96 mol

The number of moles of water produced by oxygen are less so it will limiting reactant.

3 0
3 years ago
A neutral atom becomes a positive ion when it
Alexeev081 [22]

Answer:

Neutral atoms can be turned into positively charged ions by removing one or more electrons.

Explanation:

If there is an atom that has 9 protons and 9 electrons, removing an electron from the atom will gain a postive charge.

8 0
3 years ago
Read 2 more answers
Which of the below elements will not likely form an ionic bond?
Nookie1986 [14]

Answer:

B

Explanation:

I think this is right

3 0
2 years ago
CALCULATOR
suter [353]

Answer: The possible molecular formula will be CO_2

Explanation:

Mass of C= 27.3 g

Mass of O = 72.7 g

Step 1 : convert given masses into moles.

Moles of C =\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{27.3g}{12g/mole}=2.275moles

Moles of O =\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{72.7g}{16g/mole}=4.544moles

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = \frac{2.275}{2.275}=1

For O =\frac{4.544}{2.275}=2

The ratio of C : O = 1: 2

Hence the empirical formula is CO_2

The possible molecular formula will be=n\times CO_2

5 0
3 years ago
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