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Natali5045456 [20]

2 years ago

15

When silver coins are found in ancient shipwrecks,they are coated with a black crust. What question could you ask to help you de

cide whether the silver underwent a chemical change or a physical change? Explain.

1 answer:

leonid [27]2 years ago

8 0

It went under a physical change because it (1) changed color. (2) changed form.

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C₆H₁₂O₆ + 6O₂→6CO₂ + 6H₂O + Energy

NeX [460]

Answer:

C₆H₁₂O₆ + 6O₂→6CO₂ + 6H₂O + Energy=chemical equation for cellular respiration

Explanation:

hope this help

this is james not jade

7 0

3 years ago

Consider the reaction; Mg + O2 → MgO Calculate the mass of magnesium oxide possible if 2.5 g Mg reacts with 5.0 g O2?

MAXImum [283]

Answer:

4.15g

Explanation:

Balance the reaction:

2Mg + O2 = 2MgO

Find limiting reactant from the two, by dividing miles with coefficient

2.5/24.3 = 0.103 moles/2 = 0.0515

5/16 = 0.31 moles/2 = 0.156

0.0515 is small than 0.156, so limiting reactant is Mg

Compare the ratio of Mg with MgO

Ratio is 2:2

So same moles = 0.103 moles

Mass = moles x molar mass of MgO

Mass = 0.103 x 40.3

= 4.15g

*please give brainlest*

7 0

1 year ago

Match each alkane name with its structure.

9966 [12]

C3H8 = Propane

C7H16 = Heptane

C8H18 = Octane

C4H10 = butane

C10H22 = decane

6 0

3 years ago

Read 2 more answers

B. if 6.73 g of na2co3 is dissolved in enough water to make 250. ml of solution, what is the molar concentration of sodium carbo

BARSIC [14]

Answer:- $[Na_2CO_3]=0.254M$ , $[Na^+]=0.508 M$ , $[CO_3^2^-]=0.254M$

Solution:- We are asked to calculate the molarity of sodium carbonate solution as well as the sodium and carbonate ions.

Molarity is moles of solute per liter of solution. We have been given with 6.73 grams of sodium carbonate and the volume of solution is 250.mL. Grams are converted to moles and mL are converted to L and finally the moles are divided by liters to get the molarity of sodium carbonate.

Molar mass of sodium carbonate is 105.99 gram per mol. The calculations for the molarity of sodium carbonate are shown below:

$\frac{6.73gNa_2CO_3}{250.mL}(\frac{1mol}{105.99g})(\frac{1000mL}{1L})$

= $0.254MNa_2CO_3$

So, molarity of sodium carbonate solution is 0.254 M.

sodium carbonate dissociate to give the ions as:

$Na_2CO_3(aq)\rightarrow 2Na^+(aq)+CO_3^2^-$

There is 1:2 mol ratio between sodium carbonate and sodium ion. So, the molarity of sodium ion will be two times of sodium carbonate molarity.

$[Na^+]=2(0.254M)$ = 0.508 M

There is 1:1 mol ratio between sodium carbonate and carbonate ion. So, the molarity of carbonate ion will be equal to the molarity of sodium carbonate.

$[CO_3^2^-]=0.254M$

5 0

3 years ago

In a room full of air, the air is mainly composed of Nitrogen and Oxygen molecules (both at room temperature). Find (to two sign

zloy xaker [14]

Explanation:

Expression for the $v_{rms}$ speed is as follows.

$v_{rms} = \sqrt{\frac{3kT}{M}}$

where, $v_{rms}$ = root mean square speed

k = Boltzmann constant

T = temperature

M = molecular mass

As the molecular weight of oxygen is 0.031 kg/mol and R = 8.314 J/mol K. Hence, we will calculate the value of $v_{rms}$ as follows.

$v_{rms} = \sqrt{\frac{3kT}{M}}$

= $\sqrt{\frac{3 \times 8.314 J/mol K \times 309.02 K}{0.031 kg/mol}}$

= 498.5 m/s

Hence, $v_{rms}$ for oxygen atom is 498.5 m/s.

For nitrogen atom, the molecular weight is 0.028 kg/mol. Hence, we will calculate its $v_{rms}$ speed as follows.

$v_{rms} = \sqrt{\frac{3kT}{M}}$

= $\sqrt{\frac{3 \times 8.314 J/mol K \times 309.92 K}{0.028 kg/mol}}$

= 524.5 m/s

Therefore, $v_{rms}$ speed for nitrogen is 524.5 m/s.

3 0

3 years ago