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german
3 years ago
12

Geetha took some grains of boiled rice in test tube A and Tina took boiled and chewed rice in test tube B. Both of then poured 1

-2 drops of iodine solution into the test tubes. What would they have observed? Give a reason for your answer.
Chemistry
1 answer:
Mekhanik [1.2K]3 years ago
6 0

Answer:

Test tubes A and B turn a darker blue color.

Explanation:

Based on the information provided in the question it can be said that they should have noticed that Tube A and Tube B turned a dark blue color. This is because the starch turns the solution in the test tubes into a dark blue color due to the negative reaction caused by the conversion of starch present in salivary amylase

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Reaction time is a stimulus reaponse ______ ? A ) instant B) complex. C) simple . D) automatic
lina2011 [118]
Reactions happen instantly even if some are slower than others they all happen instantly so the answer would be A.
5 0
3 years ago
Read 2 more answers
For the reaction o(g) + o2(g) → o3(g) δh o = −107.2 kj/mol given that the bond enthalpy in o2(g) is 498.7 kj/mol, calculate the
Aneli [31]
The reaction;
O(g) +O2(g)→O3(g), ΔH = sum of bond enthalpy of reactants-sum of food enthalpy of products.
ΔH = ( bond enthalpy of O(g)+bond enthalpy of O2 (g) - bond enthalpy of O3(g)
-107.2 kJ/mol = O+487.7kJ/mol =O+487.7 kJ/mol +487.7kJ/mol =594.9 kJ/mol
Bond enthalpy (BE) of O3(g) is equals to 2× bond enthalpy of O3(g) because, O3(g) has two types of bonds from its lewis structure (0-0=0).
∴2BE of O3(g) = 594.9kJ/mol
Average bond enthalpy = 594.9kJ/mol/2
=297.45kJ/mol
∴ Averange bond enthalpy of O3(g) is 297.45kJ/mol.
8 0
3 years ago
During an investigation, a student burns magnesium to form magnesium oxide. The starting mass of magnesium is measured as 21.3 g
enot [183]

Answer:

Percentage yield = 85.2%

Explanation:

Given data:

Mass of Mg = 21.3 g

Actual yield of MgO = 30.2 g

Percentage yield = ?

Solution:

Chemical equation:

2Mg + O₂ → 2MgO

Number of moles of Mg = mass/molar mass

Number of moles of Mg = 21.3 g / 24.3 g/mol

Number of moles of Mg = 0.88 mol

Now we will compare the moles of MgO with Mg.

                 Mg           :               MgO

                 2               :               2

                0.88             :             0.88

Mass of MgO:           

Mass of MgO= moles × molar mass

Mass of MgO= 0.88 mol × 40.3g/mol

Mass of MgO =  35.46 g

Actual yield of MgO = 30.2 g

Percentage yield:

Percentage yield = Actual yield/theoretical yield × 100

Percentage yield = 30.2 g/ 35.46 g × 100

Percentage yield = 85.2%

3 0
3 years ago
Given the unbalanced equation: PbCl₂ + Na₂CrO₂ ---> PbCrO₂ + NaCl. When properly balanced, the sum of the balancing coefficie
Veronika [31]

Answer:

A. 2

hope this helps :)

if you need an explanation let me know!!

3 0
3 years ago
What kind of a bond is oc2
nexus9112 [7]

Answer:

A carbon–oxygen bond is a polar convalescent bond between carbon and oxygen. Oxygen has 6 valence electrons and prefers to either share two electrons in bonding with carbon, leaving the 4 nonbinding electrons in 2 lone pairs :O: or to share two pairs of electrons to form the carbon functional group.

8 0
3 years ago
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