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3 years ago

Are watches considered as compound machines?

Chemistry

1 answer:

Alisiya [41]3 years ago

5 0

Yes. They are called compound machines because two or more simple machines were combined to create it.

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Carbohydrates like sugars and starches are made of only three elements: carbon (C), hydrogen (H), and oxygen (O). How is it poss

lara31 [8.8K]

Answer:

See explanation

Explanation:

A carbohydrate is formed from carbon, hydrogen and oxygen. These three elements are combined in every carbohydrate.

Even though carbohydrates are composed of only these three atoms, the number of atoms of these elements in each carbohydrate as well as the spatial arrangement of these atoms in each carbohydrate is not the same.

This means that different carbohydrates contain different number of carbon, oxygen and hydrogen atoms which are arranged in different ways in space. This gives room for the existence of many different types of carbohydrates all consisting of carbon, hydrogen and oxygen atoms.

8 0

3 years ago

Mendeleev’s table of elements was better accepted than those of other scientists at the time because _______________ . Moseley w

disa [49]

Answer:Answer: Mendeleev's table of elements was better accepted than those of other scientists at the time because it predicted correctly the properties of elements that had not yet been discovered. Moseley went a step further in suggesting that the elements be arranged according to atomic number

Explanation:

8 0

3 years ago

Read 2 more answers

The enthalpy change for the reaction of titanium metal with gaseous iodine is given by the following thermochemical equation: 2

julia-pushkina [17]

Answer : The enthalpy change for the reaction is, 419.5 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

The given chemical reaction is,

$2Ti(s)+3I_2(g)\rightarrow 2TiI_3(s)$ $\Delta H=-839kJ$

Now we have to determine the enthalpy change for the reaction below:

$TiI_3(s)\rightarrow Ti(s)+\frac{3}{2}I_2(g)$ $\Delta H'=?$

By reversing and then dividing the reaction by 2, we get the enthalpy change for the reaction.

The expression will be:

$\Delta H'=-\frac{(\Delta H)}{2}$

$\Delta H'=-\frac{(-839kJ)}{2}$

$\Delta H'=419.5kJ$

Therefore, the enthalpy change for the reaction is, 419.5 kJ

3 0

3 years ago

Atoms of oxygen have a total of 8 electrons. are these atoms stable, and why or why not? view available hint(s) atoms of oxygen

pychu [463]

No. Because only 6 valence

6 0

3 years ago

Consider the reaction when aqueous solutions of potassium hydroxide and ammonium nitrate are combined. The net ionic equation fo

Reil [10]

Answer: $OH^-(aq)+NH_4^+(aq)\rightarrow NH_3(g)+H_2O(l)$

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.

$KOH(aq)+NH_4NO_3(aq)\rightarrow KNO_3(aq)+NH_3(g)+H_2O(l)$

The equation can be written in terms of ions as:

$K^+(aq)+OH^-(aq)+NH_4^+(aq)+NO_3^-(aq)\rightarrow K^+(aq)+NO_3^-(aq)+NH_3(g)+H_2O(l)$

Spectator ions are defined as the ions which does not get involved in a chemical equation or they are ions which are found on both the sides of the chemical reaction present in ionic form.

The ions which are present on both the sides of the equation are potassium and nitrate ions and hence are not involved in net ionic equation.

Hence, the net ionic equation is :

$OH^-(aq)+NH_4^+(aq)\rightarrow NH_3(g)+H_2O(l)$

6 0

3 years ago