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Fed [463]
3 years ago
10

Kevin activates an instant hot pack to put in each glove while he trains for the Iditarod dog sled race in Alaska. When the hot

pack is exposed to air the iron in it reacts with oxygen to form iron (III) oxide. How could Kevin modify this device to make a longer lasting product?
Chemistry
1 answer:
Usimov [2.4K]3 years ago
6 0

Answer:

I think it's D

Explanation:

because it says when ever air hits the iron it reacts so if we make a slower release then it will take less time to get cold !

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If 28 mL of 6.2 M H2SO4 was spilled, what is the minimum mass of NaHCO3 that must be added to the spill to neutralize the acid?
Naddika [18.5K]

Answer:

The answer is 30 g of sodium hydrocarbonate

Explanation:

This is a acid-base reaction, so in order to neutralise the spilled acid, the mol of spilled acid should be calculated.

M = n / V => n = M x V = 0.028 x 6.2 = 0.1736 mol

Since 1 mol of sulfuric acid generates 2 mol of H⁺, so the mole of H⁺ is 0.3472 mol or 0.35 mol with two significant figures.

To neutralized the acid, we need at least the same mole of base, so we need at least 0.35 mol of NaHCO₃, which can be converted to its mass at 29.4 g.

Since the answer need to be expressed in two significant figures and also need to make sure to neutralize all the acid, so we will use a little excess base. The answer is 30 g.

5 0
3 years ago
Limescale removers contain sulfamic acid, H3NSO3, which reacts with minerals in hard water
I am Lyosha [343]

Answer:

0.375 moles of CaCO₃ are required

Explanation:

Given data:

Number of moles of sulfamic acid = 0.75 mol

Number of moles of calcium carbonate required = ?

Solution:

Chemical equation:

2H₃NSO₃ + CaCO₃     →        Ca(SO₃NH₂)₂ + CO₂ + H₂O

Now we will compare the moles of H₃NSO₃  and CaCO₃ .

                H₃NSO₃           :            CaCO₃  

                     2                 :             1

                   0.75              :           1/2×0.75 = 0.375 mol

Thus, 0.375 moles of CaCO₃ are required.

 

4 0
3 years ago
A river with a flow of 50 m3/s discharges into a lake with a volume of 15,000,000 m3. The river has a background pollutant conce
spin [16.1K]

Explanation:

The given data is as follows.

       Volume of lake = 15 \times 10^{6} m^{3} = 15 \times 10^{6} m^{3} \times \frac{10^{3} liter}{1 m^{3}}

        Concentration of lake = 5.6 mg/l

Total amount of pollutant present in lake = 5.6 \times 15 \times 10^{9} mg

                                                                    = 84 \times 10^{9} mg

                                                                    = 84 \times 10^{3} kg

Flow rate of river is 50 m^{3} sec^{-1}

Volume of water in 1 day = 50 \times 10^{3} \times 86400 liter

                                          = 432 \times 10^{7} liter

Concentration of river is calculated as 5.6 mg/l. Total amount of pollutants present in the lake are 2.9792 \times 10^{10} mg or 2.9792 \times 10^{4} kg

Flow rate of sewage = 0.7 m^{3} sec^{-1}

Volume of sewage water in 1 day = 6048 \times 10^{4} liter

Concentration of sewage = 300 mg/L

Total amount of pollutants = 1.8144 \times 10^{10} mg or 1.8144 \times 10^{4}kg

Therefore, total concentration of lake after 1 day = \frac{131936 \times 10^{6}}{1.938 \times 10^{10}}mg/ l

                                        = 6.8078 mg/l

                 k_{D} = 0.2 per day

       L_{o} = 6.8078

Hence, L_{liquid} = L_{o}(1 - e^{-k_{D}t}

             L_{liquid} = 6.8078 (1 - e^{-0.2 \times 1})  

                             = 1.234 mg/l

Hence, the remaining concentration = (6.8078 - 1.234) mg/l

                                                             = 5.6 mg/l

Thus, we can conclude that concentration leaving the lake one day after the pollutant is added is 5.6 mg/l.

5 0
4 years ago
Are the intersection of any two half-planes necessarily a half-plane
Mashutka [201]

Answer;

The answer is No,

Explanation;

-The intersection of two parallel half-planes A and B is either a half-plane (either A or B, when A and B have similar orientation) or the empty set (when A and B have opposite orientation).

-When A and B are not parallel, their intersection is a maximal open region bounded by the two lines that define A and B, respectively. In this case, the intersection always exists and it is never a half-plane.

6 0
4 years ago
What is the second most abundant gas in our atmosphere
Arlecino [84]
Oxygen is the second most abundant gas in our atmosphere.
5 0
3 years ago
Read 2 more answers
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