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4 years ago

Burning wood represents a chemical change. True or False?

Chemistry

2 answers:

Strike441 [17]4 years ago

7 0

True
is the answer lol

Aloiza [94]4 years ago

6 0

I'd say this is probably true.

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A sample of an unknown liquid has a volume of 30.0 mL and a mass of 6 g. What is its density? i need this hella quick

Lana71 [14]

density= mass/volume

density= 6g/30.0 ml

density= 0,2 g/ml

7 0

3 years ago

Ag(s)+CN−(aq)+O2(g)→Ag(CN)−2(aq) Express your answer as a chemical equation. Identify all of the phases in your answer. Express

Lerok [7]

Answer : The balanced redox reaction will be,

$4Ag(s)+8CN^-(aq)+O_2(g)+4H^+(aq)\rightarrow 4Ag(CN)_2^-(aq)+2H_2O(l)$

Explanation :

The given chemical equation is,

$Ag(s)+CN^-(aq)+O_2(g)\rightarrow Ag(CN)_2^-(aq)$

In the half reaction method, the number of atoms in each half reaction and number of electrons must be balanced.

The half reactions in the acidic medium are :

Reduction : $O_2(g)+4H^+(aq)+4e^-\rightarrow 2H_2O(l)$ ......(1)

Oxidation : $Ag(s)+2CN^-(aq)\rightarrow Ag(CN)_2^-(aq)+1e^-$ .......(2)

Now multiply the equation (2) by 4 and then added both equation, we get the balanced redox reaction.

Thus, the balanced redox reaction will be,

$4Ag(s)+8CN^-(aq)+O_2(g)+4H^+(aq)\rightarrow 4Ag(CN)_2^-(aq)+2H_2O(l)$

7 0

4 years ago

Chemical reactions can be detected by changes in_____. Select all that apply. temperature color overall mass of the products com

Butoxors [25]

Good morning

Chemical reactions can be detected by changes in : Temperature and color

Enjoy your day !

6 0

3 years ago

Read 2 more answers

Some nighttime partygoers wear glow-inthe-dark necklaces. the necklaces start glowing once they are ""activated"" by snapping th

8_murik_8 [283]

Answer:

Exergonic

Explanation:

The process is exergonic because it transfer energy from the system to the surrounds in the shape of light. It happens because of the Gibbs free energy (ΔG) which is lower than zero. If the reaction was Endergonic, the Gibbs free energy should be higher than zero. We can calculate it from the GIbbs-Helmholtz equation: ΔG = ΔH - T . ΔS. ΔH is enthalpy, T is the temperature and ΔS is entropy.

5 0

3 years ago

Cryolite, Na3AlF6(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. Balance the equation f

Korvikt [17]

Answer:

$55.2kgNa_{3}AlF_{6}$

Explanation:

1. First balance the equation for the synthesis of cryolite:

$Al_{2}O_{3}_{(s)}+6NaOH_{(l)}+12HF_{(g)}=2Na_{3}AlF_{6}+9H_{2}O_{(g)}$

2. Find the limiting reagent between the $Al_{2}O_{3},NaOH$ and $HF$

- First calculate the number of moles of each compound using its molar mass and the mass that reacted completely:

$13.4kgAl_{2}O_{3}*\frac{1molAl_{2}O_{3}}{101.96gAl_{2}O_{3}}*\frac{1000g}{1kg}=131molesAl_{2}O_{3}$

$55.4kgNaOH*\frac{1molNaOH}{40kgNaOH}*\frac{1000g}{1kg}=1385molesNaOH$ $55.4kgHF*\frac{1molHF}{20kgHF}*\frac{1000g}{1kg}=2770molesHF$

- Divide the number of moles obtained between the stoichiometric coefficient of each compound in the chemical reaction:

$Al_{2}O_{3}:\frac{131}{1}=131$

$NaOH:\frac{1385}{6}=231$

$HF:\frac{2770}{12}=231$

The $Al_{2}O_{3}$ is the limiting reagent because it has the smallest number.

3. Find the mass of cryolite produced:

$13.4kgAl_{2}O_{3}*\frac{1molAl_{2}O_{3}}{0.10196kgAl_{2}O_{3}}*\frac{2molesNa_{3}AlF_{6}}{1molAl_{2}O_{3}}*\frac{0.20994kgNa_{3}AlF_{6}}{1molNa_{3}AlF_{6}}=55.2kgNa_{3}AlF_{6}$

3 0

4 years ago