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butalik [34]
4 years ago
10

Where are chemicals found

Chemistry
1 answer:
Vinvika [58]4 years ago
6 0

Answer:

Most substances found in nature-such as wood, soil, and rocks-are mixtures of chemical compounds. These substances can be separated into their constituent compounds by physical methods, which are methods that do not change the way in which atoms are aggregated within the compounds.

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What is the mass number of 19/9F?<br> Your answer:<br> A. 9<br> B. 10<br> C. 19<br> D. 28
dexar [7]

the mass number of fluorine (F) is 19

C. 19

8 0
3 years ago
Ethanol (c2h5oh) melts at -114°c. the enthalpy of fusion is 5.02 kj/mol. the specific heats of solid and liquid ethanol are 0.9
Nimfa-mama [501]

Answer: 4.18925 kJ heat is needed to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.

Explanation:

Temperature of Solid C_2H_5OH=-135^oC=138 K(0^oC=273K)

Melting temperature of Solid C_2H_5OH=114^oC=159 K

Temperature of liquid C_2H_5OH=-50^oC=223K

Specific heats of solid  ethanol = 0.97 J/gK

Specific heats of liquid ethanol = 2.3 J/gK

Heat required to melt the the 25 g solid C_2H_5OH at 159 K

\Delta T_1 = 159 K - 138 K = 21 K

Q_1=mc\Delta T= 25\times 0.97J/gK\times 21 K=509.25 J

Heat required to melt and raise the temperature of C_2H_5OH upto 223 K

\Delta T_2 = 223 K - 159 K  = 64 K

Q_2=mc\Delta T= 25\times 2.3J/gK\times 64 K=3680 J

Total heat to convert solid ethanol to liquid ethanol at given temperature :

Q_1+Q_2=509.25 J+3680 J=4189.25 J=4.18925 kJ (1kJ=1000J)

Hence, 4.18925 kJ of heat will be required to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.

6 0
3 years ago
Match the following reactions with the reaction type. You may use each type more than once.
vaieri [72.5K]

Answer:

1) Decomposition

2)Double-replacement reaction

3)synthesis

4)Double-replacement reaction

5)single-replacement reaction

6)Double-replacement reaction

Explanation:

Step 1: Data given

Synthesis: This is a reaction where two or more reactants will combine to form a new, single product. This is  occurs when two or more reactants combine to form a single product.  This can be shown with the following equation.

A + B → C

A and B are the reactants to form a new product C

Decomposition: This is a reaction where 1 (more complex) compound will be broken down into 2 or more (more simple)  products.

This can be shown by the following equation:

AB → A + B

A single replacement: This is a reaction where one element wil be replaced by another element in the same compound. This can be shown by the following equation:

A + BC → B + AC

Here is the elemnt B in the compound BC, replaced by the element A, to form a new compound AC

A double-replacement: This is a reaction where the positive and negative ions of two ionic compounds will be exchanged and 2 new compounds willbe formed. This can be shown by the following equation:

AB+CD→AD+BC

A combustion reaction requires oxygen gas (O2) to produce the  products CO2 and H2O

Step 2:

1) 2HgO(s) → 2Hg(l) + O2(g)

⇒ Decomposition

2) KCl(aq) + AgNO3(aq) → AgCl(s) + KNO3(aq)

⇒  Double-replacement reaction

3) 2Na(s) + H2(g) → 2NaH(s)

⇒ synthesis

4) Mg(OH)2(aq) + 2HNO2(aq) → Mg(NO2)2(aq) + 2 H2O(l)

⇒  Double-replacement reaction

5) Ca(s) + 2AgNO3(aq) → Ca(NO3)2(aq) + Ag(s)

⇒  Single-replacement reaction

6) Al2O3(s) + H2SO4(aq) → Al2(SO4)3(aq) + H2O(l)

⇒  Double-replacement reaction

8 0
3 years ago
What volume (L) of 0.250 M HNO3 is required to neutralize a solution prepared by dissolving 17.5 g of NaOH in 350 mL of water ?
IRINA_888 [86]
<h3>Answer:</h3>

1.75 L HNO₃

<h3>Explanation:</h3>

We are given;

Molarity of HNO₃ as 0.250 M

Mass of NaOH as 17.5 g

Volume of NaOH = 350 mL

We are required to calculate the volume of 0.250 M

We are going to first write the balanced reaction:

NaOH(aq) + HNO₃(aq) → NaNO₃(aq) + H₂O(l)

Then, we calculate the number of moles of NaOH

Moles = Mass ÷ Molar mass

Molar mass of NaOH = 39.997 g/mol

          = 17.5 g ÷ 39.997 g/mol

          = 0.4375 moles

We can now calculate the number of moles of HNO₃ using the mole ratio from the equation;

Mole ratio of NaOH to HNO₃ is 1 : 1

Therefore, if moles of NaOH are 0.4375 moles then;

Moles of HNO₃ will also be 0.4375 moles

We can now calculate the volume of HNO₃

Morality = Number of moles ÷ Volume

Thus;

Volume = Number of moles ÷ Molarity

             = 0.4375 moles ÷ 0.250 M

             = 1.75 L

Therefore, the volume of HNO₃ is 1.75 L

5 0
3 years ago
The number of protons in the nucleus of the atom is equal to the atomic number. True False
fiasKO [112]
Yes it is equal,True 
7 0
3 years ago
Read 2 more answers
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