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3 years ago

Tommy was walking at a rate of 4

1 answer:

8 0

A positive acceleration indicates that the object sped up. This means that if you compare the first speed to the second, the second speed should be higher.

A negative acceleration indicates that the object has slowed down. This means that if you compare the first speed to the second, the second speed should be lower.

If an acceleration is 0, it means that it neither slowed down nor sped up.

Now let us analyze your problem by listing down the speed and the time:

At noon: 4 mi/hr
12:30 : 6 mi/hr
2:30 : 2 mi/hr

From noon to 12:30, you will notice that there is an increase in speed. This means that Tommy had a positive acceleration. (Rules out D.)

From 12:30 to 2:30, there is a decrease in speed. This would indicate that Tommy had a negative acceleration. (Rules out C.)

No speed was the same, so acceleration was never 0. (Rules out A.)

From the assumptions above, we can now deduce that the answer is B.

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Is sand an element or a compound?

Romashka-Z-Leto [24]

Neither

its a mixture

7 0

2 years ago

A 10.50 gram sample of a compound is decomposed to yield 3.40 g Na, 2.37 g S, and 4.73 g O. What is the mass percentage of each

9966 [12]

Answer:

Na = 32.4% , % S = 22.6% and %O = 45.0%

Explanation:

% Na = 3.4/10.5. × 100%

= 32.4%

%S = 2.37/10.5 × 100%

= 22.6%

% O= 4.73/10.5 × 100%

= 45.0%xplanation:

6 0

2 years ago

Describe the difference between a ball-and-stick model and a space-filling model of a compound.

Lisa [10]

A space-filling model shows the relative amount of space each atom takes up. In other words, a space-filling model can show relative sizes of atoms. However, unlike ball-and-stick or structural models, space-filling models do not show bond lengths clearly. Bonds are not really like sticks in a ball-and-stick model.

4 0

3 years ago

Why do ionic compounds conduct electric current when they are melted or dissolved in water?

erik [133]

It is beacuse the ions in the melted or aqueous ionic compound is mobile and can freely move through the fluid and conduct electricity.

4 0

3 years ago

LICUICY NICULUM

Evgen [1.6K]

Answer:

Missing component

Cl₂

H₂O

Explanation:

Reaction given:

? + 2NaBr → 2NaCl+Br

Mg+? → MgO+H2

missing component = ?

Solution:

Reaction 1

? + 2NaBr -----→ 2NaCl + Br

if we look at the reactants and products there is one element is in product side but not shown in the reactant side.

In products there are following atoms

Na (Sodium)

Cl (Chlorine)

Br (Bromine)

In Reactant there are following atoms

Na (Sodium)

Br (Bromine)

So only Chlorine is missing in the reactant side.

if we put chlorine in the reactant then this reaction will be complete

Cl + 2 NaBr -----→ 2NaCl + Br

So chlorine react with water and give sodium chloride and bromine molecule, this is a single displacement reaction and chlorine replace bromine in the above reaction

Now balance the equation

Cl₂ + 2 NaBr -----→ 2NaCl + Br₂

So, the missing component is

Cl₂

____________

Reaction 2

Mg + ? ---------→ MgO + H₂

if we look at the reactants and products there are two element in product side but not shown in the reactant side.

In products there are following atoms

Mg (Magnesium)

O (Oxygen)

H (Hydrogen)

In Reactant there is only one following atom

Mg (Magnesium)

So Oxygen and Hydrogen is missing in the reactant side.

if we put water molecule (H₂O) in the reactant then this reaction will be complete

Mg + H₂O ---------→ MgO + H₂

in this reaction magnesium (Mg) react with water (H₂O) and give magnesium oxide and hydrogen gas.

So, the missing component is

H₂O

3 0

3 years ago

Read 2 more answers