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2 years ago

Help pleaseeeeeeeee just need 4 answers

Chemistry

1 answer:

larisa86 [58]2 years ago

8 0

Answer:

Here, acceleration due to gravity(a) is assumed as 10m/s².We can also take it as 9.8m/s²

Explanation: $Brick) Weight=m * a=1 * 10=10N\\Bag of books) Mass=f/a=25/10=2.5kg\\Bag of potatoes) Weight=m * a=10 * 10=100N\\Bag of cement) Mass=f/a=400/10=40kg$

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You have a 28.2-g sample of a metal heated to 95.2°c. you drop it in a calorimeter with 100. g of water at 25.1°c. the final tem

Vlad [161]

The heat lost by the metal should be equal to the heat gained by the water. We know that the heat capacity of water is simply 4.186 J / g °C. Therefore:

100 g * 4.186 J / g °C * (31°C – 25.1°C) = 28.2 g * Cp * (95.2°C - 31°C)

4 0

3 years ago

Three mixtures were prepared from three very narrow molar mass distribution polystyrene samples with molar masses of 10,000, 30,

8_murik_8 [283]

Answer:

(a). 46,666.7 g/mol; 78,571.4 g/mol

(b). 86950g/mol; 46,666.7 g/mol.

(c). 86950g/mol; 43,333.33 g/mol

Explanation:

So, we are given the molar masses for the three samples as: 10,000, 30,000 and 100,000 g mol−1.

Thus, the equal number of molecule in each sample = ( 10,000 + 30,000 + 100,000 ) / 3 = 46,666.7 g/mol.

The average molar mass = [ ( 10,000)^2 + (30,000)^2 + 100,000)^2] ÷ 10,000 + 30,000 + 100,000 = 78,571. 4 g/mol.

(b). The equal masses of each sample = 3/[ ( 1/ 10,000) + (1/30,000 ) + (1/100,000) ] = 20930.23 g/mol.

Average molar mass = ( 10,000 + 30,000 + 100,000 ) / 3 = 46,666.7 g/mol.

(c). Equal masses of the two samples = (0.145 × 10,000) + (0.855 × 100,000)/ 0.145 + 0.855 = 86950g/mol.

The weight average molar mass = 1.7 + 10,000 + 100,000/ 1.7 + 1 = 43,333.33 g/mol.

6 0

3 years ago

How many grams of sodium bicarbonate are needed to completely react with a 0.892 m phosphoric acid solution that contains to 45.

SVETLANKA909090 [29]

Answer:

umm idk if I was right or not

7 0

3 years ago

A transfer of heat within a liquid or gas that involves warm particles moving in currents is?

myrzilka [38]

It is called convection. When warm air, or current, moves up and disperse outwards as cold air, or current, moves into the warmer region.

3 0

3 years ago

Read 2 more answers

Balance the following redox equation using the smallest integers possible and select the correct coefficient for the hydrogen su

goldfiish [28.3K]

Answer:

Coefficient of $HSO_{3}^{-}$ is 5

Explanation:

Oxidation: $MnO_{4}^{-}(aq)\rightarrow Mn^{2+}(aq)$

Balance O and H in acidic medium: $MnO_{4}^{-}(aq)+8H^{+}(aq)\rightarrow Mn^{2+}(aq)+4H_{2}O(l)$
Balance charge : $MnO_{4}^{-}(aq)+8H^{+}(aq)+5e^{-}\rightarrow Mn^{2+}(aq)+4H_{2}O(l)$ .............(1)

Reduction: $HSO_{3}^{-}\rightarrow SO_{4}^{2-}$

Balance O and H in acidic medium : $HSO_{3}^{-}(aq)+H_{2}O(l)\rightarrow SO_{4}^{2-}(aq)+3H^{+}(aq)$
Balance charge : $HSO_{3}^{-}(aq)+H_{2}O(l)-2e^{-}\rightarrow SO_{4}^{2-}(aq)+3H^{+}(aq)$ ..............(2)

$[2\times eq(1)]+[5\times eq(2)]$ -

Balanced equation: $2MnO_{4}^{-}(aq)+5HSO_{3}^{-}(aq)+H^{+}(aq)\rightarrow 2Mn^{2+}(aq)+5SO_{4}^{2-}(aq)+3H_{2}O(l)$

Coefficient of $HSO_{3}^{-}$ is 5

8 0

2 years ago